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▸ Biology is a natural science concerned with the study of life and living organisms, i.e., plants and animals. It is classified into two part: Botany and zoology. ▸ Study of plants is called Botany and study of animals is called Zoology. Zoology and Botany are collectively called Biology. The term 'Biology' was coined by Lamarck and Treviranus. ▸ The scientist who gave his thought for the first time about the life of plants and animals was Aristotle. That's why he is known as the Father of Biology. He is also known as the Father of Zoology. ▸ Theophrastus is known as Father of Botany.
▸ They have cellular organisation and also respire, i.e., take in O2 and evolve CO2. ▸ Metabolism is one of the most important characteristic feature of living organism. It comprises two phases that are anabolism (constructive phase) and catabolism (destructive phase.) ▸ They take nutrition for their growth. ▸ They have tendency to reproduce. ▸ They have the ability to respond to changes in both internal and external environment i.e., they have sensitivity. Their survival chances are maximum. ▸ They move from place to place as animals or some bacteria. Plants cannot move but some movement can occur in plants.
▸ The Cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life and is often called the building block of life. ▸ The branch of biology which deals with the study of cell, is called Cytology. ▸ Robert Hooke coined the term cell when he saw honey-comb like structure in the section of cork. However, he only discovered cell wall. ▸ The first living cell was discovered by Leeuwenhoek.
These are of two types 1. Prokaryotic Cells (Pro = primitive, karyos = nucleus) These are primitive cells, lacking a well defined nucleus and most of the other cell organelles, e.g., bacterial cell. 2. Eukaryotic Cells (Eu = true, karyos = nucleus) These have a well defined nucleus and membrane bound cell organelles. These are present in unicellular and multicellular plant and animal cells. Differences between Prokaryotic and Eukaryotic Cell
Simplest and primitive in nature.
Developed and comparatively complex in nature.
Lacks nuclear envelope
Nucleus is present with elaborate nuclear envelope
Membrane bound cell organelles are absent.
Membrane bound cell organelles are present.
Single naked chromosome present.
Many chromosomes are present.
Cell division is direct.
Cell division occurs by mitosis or meiosis.
Facts about Cell ▸ The largest known cells are unfertilised Ostrich egg cells (size 6 inch diameter). ▸ The smallest cell is of PPLO (Mycoplasma gallisepticum of size 0.1-0.3m). ▸ Human nerve cell is the longest animal cell. ▸ Largest unicellular plant is Acetabularia (10 cm) and animal is Amoeba (1 mm). ▸ The largest human cell is the female ovumand the smallest human cell is the red blood cell.
A typical cell consists of cell wall and protoplasm.
It is the living fluid matter present inside the plasma membrane. The fluid present outside the nuclear membrane is called cytoplasm and the fluid present inside the nuclear membrane is called nucleoplasm. Deutoplasm is the non-living matter of the cell.
It is present in plant cells, bacteria, fungi, algae and some archaea. It is composed of cellulose in plants and chitin in fungi. It is non-living. Its main function is to provide shape and rigidity to the cell.
The cell is enclosed by a thin membrane called the cell membrane or plasmalemma. It is composed of proteins and phospholipid molecules. It is elastic, living and selectively permeable, i.e., provide passage for various substances.
▸ It was discovered by R Altman in 1880 and the term mitochondria was coined by Carl Benda. ▸ It is bounded by a double membrane. The inner membrane has many folds, called the cristae. Fluid (called matrix) is present on interior, which contains many enzymes and coenzymes. It is a semi- autonomous (can form its own copies) organelle and is called power house of the cell because in it, stepwise oxidation of fuel occurs which results in release of chemical energy. This energy is stored in the form of ATP.
▸ These are present only in plant cells and are of three types– chloroplasts (green), leucoplasts (white) and chromoplasts (of various colours except green). Chloroplast is the site of photosynthesis as it contains chlorophyll, while leucoplasts are storage plastids. Chloroplast is called the kitchen of the cell. ▸ The red colour of tomatoes is due to the presence of lycopene pigment, i.e., chromophore. ▸ The colour of carrot is due to carotene pigment.
It was discovered by KR Porter. These are hollow membranous system having ribosomes (thus called Rough ER) or no ribosomes (thus called Smooth ER). Rough endoplasmic reticulum is the site of protein synthesis, while smooth endoplasmic reticulum is the site of synthesis of steroids and detoxification.
It was discovered by Camillo Golgi. It is made up of sac-like flattened structures and play an important role in secretion, transportation and acrosome formation.
Nobel Prize in Physiology and Medicine 2013 The Nobel Prize in Physiology or medicine 2013 was awarded jointly to James E Rothman, Randy W Schekman and Thomas C Sudhof for their discoveries of machinery regulating vesicle traffic, a major transport system in our cells. In general, we call it Golgi body. Randy Schekman discovered a set of genes that were required for vesicle traffic. James Rothman discovered machinery that allows vesicle to fuse with their targets to deliver the stored matter..
Ribosomes were discovered by GE Palade. These are minute, non-membranous particles, composed of RNA and protein. 70 S type of ribosomes are found in prokaryotes, while 80 S type in eukaryotes. These are the site of protein synthesis.
▸ Lysosomes were discovered by de Duve. These are polymorphic organelles having hydrolytic enzymes. These enzymes function at (acidic) pH ~ 5. These are sometimes called suicidal bags of the cell. ▸ Lysosome helps in carcinogenesis, i.e., conversion of a normal cell into cancerous cell.
It was discovered by T Boveri. It is composed of two set of centrioles and participate in the formation ofmitotic spindle during cell division.
These are non-living reservior, bounded by a membrane called tonoplast. Pigment anthocyanin is present in the cell vacuole, which provide colour to flowers. It stores toxic metabolic waste and helps in osmoregulation.
It was discovered by Robert Brown. It contains nucleoplasm, nucleolus and chromatin material. Nucleolus is rich in protein and RNA. All this material is covered up by a nuclear membrane. Chromatin is the controlling centre of cell as it form chromosomes.
Chromosome is thread-like structure, found in the nucleus. Bead-like structures found on chromosome are called genes, which are made up of DNA and are the carrier of genetic information from generation to generation. Chromosomes are units of inheritance. In some viruses e.g. retrovirus, RNA is the genetic material. Differences between Plant and Animal Cell
It has cell wall.
Cell wall is usually absent.
Plastids are found.
Plastids are usually absent.
Centrioles and centrosome are absent.
Centrioles and centrosomes are found in all cells.
A big vacuole is present.
Vacuole is absent or very small in size.
These contain the genetic instructions used in the development and functioning of all known living organisms. These are of two types : DNA and RNA.
▸ DNA was discovered by James D Watson and Francis Crick, who got Nobel Prize for this discovery. ▸ It is a long polymer made from repeating units called nucleotides. ▸ Each nucleotide consists of a nucleoside (i.e. nitrogenous base and deoxyribose sugar) and a phosphate group, joined together by phosphodiester bonds. ▸ It has four bases, i.e. adenine, guanine, cytosine and thymine. ▸ Adenine and guanine are the purine bases; cytosine and thymine are pyrimidine bases.
▸ It is also made up of a long chain of nucleotides. ▸ Each nucleotide consists of a nitrogenous base, a ribose sugar, and a phosphate group. ▸ It contains uracil in place of thymine. ▸ RNA is of three types— mRNA (messenger RNA) rRNA (ribosomal RNA) tRNA (transfer RNA) These three RNA's take part in protein synthesis.
▸ It is the process by which a cell increase in number. It is essential for the growth, development and repair of the body. ▸ It is of two types – Mitosis and Meiosis (i) Mitosis It occurs in unicellular organism during asexual reproduction. Each mitotic cell division results in the formation of two daughter cells having number of chromosomes equal to the parent cell. Tumour or cancer is a result of uncontrolled mitosis. (ii) Meiosis It occurs in reproductive cells and is called reduction division because of the presence of single set of chromosomes (i.e., half of the parent chromosomes). It results in the formation of four daughter cells. ▸ Exchange of genetic material occurs between chromatids (branches of chromosome) of a diploid set during pachytene stage of meiosis and is known as crossing over.
Biomolecules are the substances that are essential for a living being to perform the basic functions, e.g., carbohydrates, proteins, lipids (fats), nucleic acids and vitamins.
▸ It was believed that these are the organic compounds which have carbon, hydrogen and oxygen in the ratio of 1 : 2 : 1 but starch (C6H10O5)n and some others are exceptions. So this definition has been changed. According to modern definition, these are the polyhydroxy aldehydes and ketones or their derivatives. ▸ These are the source of energy and about 50-75% energy is obtained by the oxidation of carbohydrates. ▸ The main end product of carbohydrate digestion is glucose, which is called blood sugar. It oxidises to give energy along with CO2 and H2O. Differences between DNA and RNA
It usually occurs inside nucleus and in some cell organelles like mitochondria and chloroplast.
Very little RNA occurs inside nucleus. Most of it is found in the cytoplasm.
DNA is the genetic material except in some viruses.
RNA is not the genetic material except in certain viruses, e g. ., HIV, reovirus.
It is double stranded with the exception of some viruses like φ × 174.
RNA is single stranded with the exception of some viruses, e g. ., double stranded in T2, T4, T6 bacteriophage.
DNA shows regular helical coiling.
There is no regular coiling except in parts of RNA.
It contains deoxyribose sugar.
It contains ribose sugar.
Nitrogen base thymine occurs in DNA along with other three i.e. adenine, cytosine and guanine.
Thymine is replaced by uracil in RNA. The other three are adenine, cytosine and guanine.
It replicates to form new DNA molecules.
It cannot replicate itself except in RNA-RNA viruses.
DNA controls heredity, evolution, metabolism, structure and differentiation.
RNA controls only protein synthesis.
▸ 1 gm glucose provides about 17 kJ energy or 4.2 kcal energy. ▸ Carbohydrates are better fuel as compared to proteins and fats as they readily decompose to give energy. ▸ Main sources of carbohydrates are wheat, maize, rice, potato etc. The carbohydrates are categorised into following three types
▸ These are simple sugars, which cannot be hydrolysed further, e.g., ribose, glucose, fructose, galactose etc. ▸ In human beings, blood glucose level is 100-120 mg/mL. Extra glucose, if any, is converted into glycogen in the liver by a process called glycogenesis. ▸ D-fructose is the sweetest of all sugars and is found in fruit juice, honey etc.
▸ They release 2-10 monosaccharides on hydrolysis, like disaccharides, e.g. sucrose, lactose maltose etc and trisaccharides, like raffinose etc. ▸ Sucrose is also called invert sugar. It gives glucose and fructose when subjected to hydrolysis.
▸ They release more than ten monosaccharides on hydrolysis. These are non-sugars, i.e., do not have sweet taste, e.g., cellulose, glycogen and starch. ▸ Cellulose is found in plant cell wall and is digested by ruminants (like cow, goat, buffalo, etc), but not by carnivorous or omnivorous animals like human beings. Thus, it acts as roughage in case of human beings.
▸ Carbohydrates provide energy, that acts as reserve food, help in the synthesis of nucleic acid and form exoskeleton of animals. Excessive intake of carbohydrate results in digestive problems and obesity.
These are found in all living cells. These are the compounds of carbon (C), hydrogen (H), oxygen (O), nitrogen (N) and sulphur (S). These form 15% part of human body. Snake venom, ricin of castor and bacterial toxins are proteinaceous in nature. Main sources of protein are groundnuts, soyabean, pulses, fish etc.
▸ These are important for the growth and repair of the body (75% of our body is protein only). However, in the deficiency of carbohydrates, these acts as the source of energy. Protein also control the development of genetic characters. ▸ Deficiency of protein causes Kwashiorkor (a disease in which hands and legs of children get slimmed and the stomach comes out) and Marasmus (a disease in which muscles of children are loosened). Kwashiorkor occurs in children between 1 to 5 years of age and marasmus in children below 1 year.
▸ These are also the compounds of carbon (C), hydrogen (H) and oxygen (O). Chemically, these are the ester of glycerol and fatty acids. These are present in cytoplasm, cell wall etc. ▸ The main source of fats are ghee, butter, almond, cheese, egg yolk, meat, soyabean etc. ▸ Fats are digested by enzymes called lipases in the small intestine. Generally, at 20°C, these are in solid state but if their state is liquid at this temperature, these are termed as oils. ▸ Fatty acids are of two types- Saturated and Unsaturated. Saturated fatty acids are found in coconut oil and palm oil, while unsaturated fatty acids are found in fish oil and vegetable oil. ▸ Excess of saturated fats raises the level of blood cholesterol and may cause arteriosclerosis. This may lead to heart attack.
The main functions of lipids are ▸ These provide twice the energy than that from carbohydrates. ▸ These remain under the skin and prevents the loss of heat from the body.
▸ Deficiency of fat results in dryskin and weight loss. ▸ If fat is in excess, the body gets fatty and result in several heart diseases and high blood pressure. ▸ The skin fat, in case of whales and seals, forms a thick layer called the blubber. It acts as reserve food and also maintains the body temperature.
▸ It was first discovered by FG Hopkin. However, the term vitamin was coined by C Funk. ▸ Vitamin is an organic compound, which cannot be synthesised in sufficient quantities by an organism and must be obtained from the diet. ▸ They provide no calories, they only regulate chemical reactions occurring in the metabolism of the body. These are divided into two groups 1. Fat soluble vitamin, viz. vitamin- A, D, E and K. 2. Water soluble vitamin, viz. vitamin-B and C. ▸ Vitamin-B12 contains cobalt. Vitamin-D is synthesised in our skin by the action of ultraviolet rays of the sunlight. Vitamin-K is synthesised in our colon by the bacteria. ▸ Water soluble vitamins normally do not show hypervitaminosis (this disease occurs due to excess intake of vitamins) as excess of these vitamins is normally excreted through urine. ▸ In balanced diet, all the important nutrients (like carbohydrate, protein, fats, vitamins etc.) are available in sufficient quantity. Vitamins, their Deficiency Diseases and Sources
Vitamin
Chemical Name
Deficiency Disease
Vitamin-A
Retinol, carotenoids
Night-blindness(Nyctalopia) , Hyperkeratosis, Keratomalacia
Orange, green vegetables, carrots, pumpkin, squash and spinach.
Vitamin-D
Calciferol
Rickets and Osteomalacia
Fish, eggs, liver and mushrooms.
Vitamin-E
Tocopherols, tocotrienols
Infertility
Many fruits and vegetables.
Vitamin-K
Phylloquinone
Non-clotting of blood
Green vegetables
Vitamin-B1
Thiamine
Beri-beri, Wernicke-Korsakoff syndrome
Oatmeal, rice, vegetables, cauliflower, potatoes, liver and eggs.
Vitamin-B2
Riboflavin
Cracking of skin, reddish eye, cracking of tongue
Dairy products, bananas, popcorn and green beans.
Vitamin-B3
Niacin and nicotinic acid
Pellagra,Glossitis
Meat, broccoli and avocados.
Vitamin-B5
Pentothenic acid
Premature greying of hair (Achromotrichia),
Meat, fish, eggs, many vegetables, mushrooms.
Vitamin-B6
Pyridoxine
Dermatitis, anaemia, mental disorder
Meat, vegetables, tree nuts and bananas.
Vitamin-B7
Biotin
Dermatitis, enteritis and anaemia
Raw egg yolk, liver, peanuts and vegetables.
Vitamin-B9
Folic acid, folinic acid
Megaloblastic anaemia and birth defects.
Leafy vegetables, pasta, bread, cereal and liver.
Vitamin-B12
Cyanocobalamin (contains cobalt)
Pernicious anaemia
Meat and other animal products.
Vitamin-C
Ascorbic acid
Scurvy (Sailer's disease)
Peppers, citrus fruits.
▸ The universe is made up of matter and energy. Scientists believe that it was formed about 10 to 13 billion years ago as a vast, dense, red-hot and rotating gaseous cloud of cosmic dust called the 'primaeval matter or 'ylem'. ▸ Two hypothesis i.e., Big -Bang (universe formation through a very big explosion) and Nebular (universe formation by the condensation of gaseous cloud) were given to explain origin of Earth.
▸ Life originated on Earth about 3.5 billion years ago. Some philosophical theories like special creation, spontaneous generation, Biogenesis, panspermia (life originated in the form of pansperms from some unknown part of the universe) or cosmozoic and catastrophism (life orginated suddenly from inorganic matter) were given to explain origin of life. ▸ The first scientific account of the origin of life was given by Russian scientist AI Oparin in his book 'Origin of life'. ▸ The primitive atmosphere contained hydrogen, methane, ammonia and water vapour. In it, oxygen and ozone were absent. Thus, it was believed that life is originated from inorganic substances by a series of complex reaction. ▸ Hydrogen atoms were most numerous and most reactive in the primitive atmosphere. First, these combined with all available oxygen atoms, forming water and leaving no free oxygen atoms. Thus, the primitive atmosphere was 'reducing' unlike the present 'oxidising' atmosphere. This was also supported by Miller and Urey in 1953. ▸ In Miller-Urey experiment, a mixture of water, hydrogen, methane and ammonia was cycled through an apparatus and the organic compound, amino acids were obtained.
More and more creation of organism by gradual changes from low category animal to higher animal is called organic evolution. There are several evidences regarding organic evolution.
On the basis of morphology (outer appearance) and anatomy (inner structure), several evidences have been described as follows
▸ The organs which are similar in basic structure and origin but dissimilar in function are called homologous organs, e.g., wings of bat, cat's paw, front foot of horse, human's hand and wings of birds. ▸ These show divergent evolution.
▸ The organs which are similar in shape and function but dissimilar in their origin and development. e.g., wings of insects, birds and bats, eyes of octopus and mammals. ▸ They show convergent evolution.
▸ These are degenerate, non-functional organs which were functional earlier. ▸ Human body has been described to possess about 90 vestigial organs. Some of these are muscles of ear pinna, canine teeth and third molar teeth, body hairs, vermiform appendix, nictitating membrane of eye, caudal vertebral (coccyx or tail bone) etc.
It is the sudden reappearance of some ancestral features. Appearance of thick body hair, large canines, monstral face, short temporary tails, extra nipples etc are examples of atavism.
Connecting link is one which exhibit characteristics of more than one groups. Intermediate Forms between Two Groups of Organisms
Virus
Living and non-living
Euglena (Protozoa)
Plants and animals
Proterospongia (Protozoa)
Protozoa and Porifera
Neopilina (Mollusca)
Annelida and Mollusca
Balanoglossus (Chordata)
Non-chordata and Chordata
Dipnoi (Lung fish)
Pisces and Amphibia
Archaeopteryx (Aves)
Reptiles and Aves
Prototheria (Mammalia)
Reptiles and Mammalia
▸ Jean-Baptiste de Lamarck gave the idea that an organism can pass on characteristics that it acquired during its lifetime to its offspring (also known as heritability of acquired characteristics). ▸ Lamarck's theory of evolution was published in Philosophie Zoologique and had four propositions, viz 1. Living organisms and its parts tend to increase in size due to internal force of life. 2. Formation of new organs is the result of a new need and new involvement. 3. Individuals lose characteristics that they do not require (or use) and develop characteristics that are useful. 4. Individuals inherit the traits of their ancestors.
▸ Darwin's theory of evolution was Origin of Species by Natural Selection. ▸ The theory consists of five propositions, they are 1. Overproduction or enormous fertility 2. Struggle for existence 3. Variation and heredity 4. Survival of the fittest or natural selection 5. Origin of species.
▸ Hugo de Vries proposed the theory of mutation, while working on Oenothera lamarckiana plant. ▸ Mutations are discontinuous variations. ▸ Mutations are due to changes in chromosomes, genes and DNA. ▸ These may or may not be inherited.
According to it, the five basic factors are 1. Gene mutation 2. Changes in chromosome structure and number 3. Genetic recombination 4. Natural selection 5. Reproductive isolation First three factors are responsible for genetic variablity. ▸ Devonian period is known as Age of fishes. ▸ Mesozoic era is known as Age of Reptiles. ▸ Coenozoic era is known as Age of Mammals.
In Linnaeus time, a two kingdom system of classification with Plantae and Animalia kingdomwas developed. The system did not distinguish between the eukaryotes and prokaryotes, unicellular and multicellular and photosynthetic organisms.
RH Whittaker (1969) proposed a five kingdom classification. The kingdom named were Monera, Protista, Fungi, Plantae and Animalia.
Storer and Usinger classified animals into following phylums
▸ These are unicellular animals, i.e., made up of only one cell. ▸ In these, all the metabolic activity like digestion, respiration, excretion and reproduction takes place in unicellular body. ▸ Respiration and excretion take place through diffusion. e.g., Amoeba, Plasmodium, Euglena etc. Phylum–Porifera ▸ These are found in marine water and have porous body. The pores are called ostia. These are multicellular animals. ▸ Their skeleton is made up of minute calcareous or siliceous spicules. e.g., Sycon, Sponge etc.
▸ These are aquatic animals, have thread-like structures called tentacles around the mouth which help in holding the food. ▸ They have specialised cnidoblast cell to help in catching the food. ▸ Phenomenon of polymorphism (many forms) and metagenesis (alternation of generation) are associated with coelentrates. e.g., Hydra, Jelly fish, Sea Anemone etc. ▸ Hydra has a tendency of regeneration of body organs.
▸ Animals of this phylum have alimentary canal with single opening, anus is absent. ▸ Excretion takes place by flame cells. ▸ There is no skeletal system such as, respiratory system, circulatory system etc. ▸ These are hermaphrodite animals (males are not separated from females). e.g., Planaria, Liver fluke, Tape worm etc.
▸ These are long, cylindrical, unsegmented worms. ▸ Their alimentary canal is complete in which mouth and anus both are present. ▸ There is no circulatory and respiratory system but nervous system is developed. Excretion takes place through protonephridia. ▸ They are unisexual. ▸ Most forms are parasitic but some are free living in soil and water. e.g., Ascaris, Threadworm, etc. ▸ Threadworm is found mainly in the anus of child. Due to which children feel itching and often vomits. Some children urinate on the bed at night. Characteristics of the Five Kingdoms
Character
Monera
Protista
Fungi
Plantae
Animalia
Cell type
Prokaryotic
Eukaryotic
Cell wall
Non-cellulosic
Present in some
Present
Nuclear membrane
Body organisation
Cellular
Multicellular/ loose tissue
Tissue/ organ
Tissue/ organ/organ system
Mode of nutrition
Autotrophic and heterotrophic
Heterotrophic
Autotrophic
Examples
Bacteria archaebacteria cyanobacteria and some primitive fungi
Amoeba Euglena Dinoflagellates
Acholrophyllus, heterotrophic fungi
Multicellular eukaryotic plants
Multicellular animals
▸ Their body is long, thin, soft and metamerically (truly) segmented. ▸ Alimentary canal is well-developed. ▸ These are the first to have proper organ systems. ▸ Nervous system is normal and blood (called haemolymph) is red (iron rich haemoglobin). ▸ Their blood flows in closed vessels. ▸ Like in earthworm, there are five pairs of blood vessels called as heart. ▸ They respire through skin, in some animals respiration takes place through coelom. ▸ Excretion by nephridia. ▸ They move through setae made up of chitin. e.g. Earthworm, Nereis, Leech etc.
▸ Arthropoda is the largest phylum (contains maximum number of animals and its existence is recorded for maximum period over the Earth). ▸ Jointed leg is their main feature. ▸ Their body is divided into three parts–head, thorax and abdomen. ▸ Circulatory system is open type. Cockroach's heart has 13 chambers. ▸ Trachea or book lungs, body surface are respiratory organs. e.g., Cockroach, Prawn, Crab, Bug, Fly, Mosquito, Bees, etc. ▸ Insects generally have six feets and four wings. ▸ Ant is a social animal which reflects division of labour. ▸ Termite is also a social animal which lives in colony.
▸ Their body is soft and divided into head and muscular foot. ▸ Mantle is always present in it, which secretes a hard calcareous shell. ▸ Their alimentary canal is welldeveloped. ▸ Respiration takes place through gills or ctenidia. Blood is colourless. ▸ Excretion takes place through kidneys. e.g., Pila, Aplysia (Sea rabbit), Doris (Sea lemon), Octopus (Devil-fish), Sepia (Cuttle-fish). ▸ Eyes of octopus are similar to chordate eyes.
▸ All the animals in this group are marine. They have water vascular system. Brain is not developed in nervous system. ▸ They have a special capacity of regeneration. ▸ These are the only invertebrate animals which contain proper bone like structures (ossicles). e.g., Star fish, Sea urchin, Sea cucumber etc.
▸ They have notochord. A dorsal hollow tubular nerve cord and paired pharyngeal gill slits at some stage of their life span. ▸ In advanced forms, notochord changes to vertebral column, nerve cord develops to brain and spinal cord and pharyngeal gill slits to structures of jaw attachment. ▸ This phylum is sub-divided into two sub-phylum, i.e., Protochordata and Vertebrata. Some main classes of phylum– Chordata are as follows
▸ These are aquatic animals (cold-blooded animals). Their heart pumps only impure blood and have two chambers. ▸ Respiration takes place through gills. e.g., Trygon, Scoliodon, Torpedo etc.
▸ These are found both on land and water. All of them are cold-blooded. ▸ Respiration takes place through gills, skin and lungs. ▸ They have three chambered heart. e.g., Frog, Necturus, Toad, Icthyophis, Salamander.
▸ These are crawling animals. ▸ These are cold-blooded and contains two pair of limbs. ▸ The skeleton is completely flexible. ▸ Respiration takes place through lungs. ▸ They have 3 1 2 chambered heart (four chambered in crocodile). ▸ Their eggs are covered with shell made up of calcium carbonate. e.g., Lizard, Snake, Tortoise, Crocodile, Turtle, Sphenodon etc. ▸ Cobra is the only snake which makes nests. ▸ Heloderma is the only poisonous lizard. ▸ Sea snake is also called Hydrophis belcheri. It is the world's most poisonous snake.
▸ The animals of this group are warm-blooded tetrapod vertebrates with flight adaptation. ▸ Their fore-feet are modified into wings to fly. ▸ They respire through lungs. ▸ Birds have no teeth, beak helps in feeding. ▸ They have a single ovary and pneumatic bones. e.g., Crow, Peacock, Parrot etc. ▸ Flightless birds are Kiwi and Emu. ▸ Largest bird is Ostrich. ▸ Smallest bird is Humming bird. ▸ Largest zoo in India is Alipur (Kolkata) and the largest zoo of the world is Cruiser National Park in South Africa.
▸ These are warm-blooded animals. ▸ Tooth comes twice in these animals (diphyodont). ▸ There is no nucleus in their red blood cells (except in camel and llama). ▸ Skin of mammals contains hair. ▸ External ear is present. Mammalia is divided into three sub-classes ▸ Prototheria It lays eggs, e.g., Echidna. ▸ Metatheria It bears the immature child, e.g., Kangaroo. ▸ Eutheria It bears the well developed child, e.g., Humans. They give birth to young ones, but Echidna and Platypus are the egg laying mammals.
The human skin (integumentary) is composed of a minimum of three major layers of tissue, the epidermis, dermis and hypodermis.
The top layer of skin is made up of epithelial cells and does not contain blood vessels.
▸ It gives elasticity to the integument, allowing stretching and conferring flexibility, while also resisting distortions, wrinkling and sagging. ▸ Nails grow 1 mm per week on an average. ▸ Protein, keratin stiffens epidermal tissue to form finger nails.
▸ It is made up of adipose tissue. It performs several important functions 1. Protect against invasion by infectious organisms. 2. Protect the body from dehydration. 3. Maintain homeostasis. 4. Act as a receptor for touch, pressure, pain, heat and cold. 5. Protect the body against sunburns by secreting melanin. 6. Generate vitamin-D through exposure to ultraviolet light. 7. Store water, fat, glucose and vitamin-D.
Animals are not able to synthesise their own food, therefore they obtain it from outside environment for their nutritional requirements.
▸ These are metals, non-metals and their salts other than the four elements—carbon, hydrogen, nitrogen and oxygen and constitute about 4% of total body weight. ▸ Milk, eggs, meat, fruit, food, vegetables etc are the sources of minerals. Minerals are of two types 1. Macronutrients These are required in large amount, e.g., calcium (Ca), phosphorus (P), potassium (K) etc. 2. Micronutrients These are required in very small amount (less than 1 g), e.g., iodine (I), iron (Fe), zinc (Zn) etc. Minerals and their Functions in the Body Mineral Major Food Source Uses Deficiency DiseaseMacronutrients
Uses
Calcium (Ca)
Milk, cheese, bread and vegetables.
Muscle contraction, nerve action, blood clotting and the formation of bone.
Tetany and rickets.
Phosphorus (P)
Cheese, eggs, pea nuts and most foods.
Bone and tooth formation, energy transfer from foods, DNA, RNA and ATP formation.
Sulphur (S)
Dairy products, meat, eggs and broccoli.
Formation of thiamine, keratin and coenzymes.
Disturbed protein metabolism
Potassium (K)
Potatoes, meat and chocolate.
Muscle contraction, nerve action, active transport.
Nervous disorder, poor muscles leading to paralysis.
Muscle contraction, nerve action and active transport.
Nervous, depression, muscular cramps, pH disbalance
Anion/cation balance and gastric acid formation.
Loss of appetite muscle cramps.
Formation of bone, formation of coenzymes in cell respiration.
Irregularity of metabolism.
Iron (Fe)
Liver, kidney, red meat, cocoa powder and water cress
Formation of haemoglobin, myoglobin and cytochromes.
Anaemia and low immunity.
Fluorine (F)
Water supplies, tea, sea food, meat, liver and beans.
Resistance to tooth decay.
Weak teeth (if present in excess causes mottling of (teeth)
Zinc (Zn)
Meat, liver and beans.
Enzyme activation and carbon dioxide transport.
Anaemia, retarted growth, weak immunity and fertilty.
Copper (Cu)
Liver, meat and fish.
Enzyme, melanin and haemoglobin formation.
Anaemia, weak blood vessels and connective tissues.
lodine (I)
Seafood, iodised salt and fish.
Thyroxine production
Goitre
Manganese (Mn)
Tea, nuts, spices and cereals.
Bone development and enzyme activation.
Irregular growth of bones and connective tissues.
Chromium (Cr)
Meat and cereals.
Uptake of glucose.
Irregular metabolism.
Cobalt (Co)
Meat and yeast.
Synthesis of vitamin- B12, formation of red blood cells
Anaemia
About 70% of the human body consists of water. Two-third of water exists inside cells, the other one-third is outside the cells in tissue fluid and blood plasma. It is essential for digestion, transportation, excretion and to regulate body temperature. Many factors affects the health of human body. One of them is adulteration.
Addition of undesirable, cheap and harmful substances in the food is called food adulteration. Indian Standards Institution (ISI) Mark and Agmark (Agricultural marketing) are given by the Bureau of Indian Standards after testing the purity and quality of material and food respectively. Some Common Adulterants in Food
Milk, curd and cheese
Water and urea
Sweets
Saccharin, harmful colour
Ghee
Vanaspati and animal fats
Cereals
Stones, sand and grit
Dhania powder
Powdered horse dung
Haldi powder
Lead chromate
Metanil yellow
Edible oils
Argemone oil
Black pepper
Papaya seed
The human digestive system consists of alimentary canal and digestive glands. The alimentary canal consists of mouth, (having teeth and tongue) oesophagus, stomach, small intestine and large intestine.
▸ With the help of teeth the food is chewed. Teeth are of four types Incisors (for cutting) Canines (for tearing) Premolars (for chewing) Molars (for chewing and grinding) ▸ The number of teeth are different in different animals. These are represented by dental formula as I C Pm M – Upper half jaw I C Pm M – Lower half jaw Where, I – Incisors, C – Canines, Pm – Premolars and M – Molars. ▸ Premolars and molars are called cheek teeth. Milk teeth do not include molar teeth. ▸ In humans, first teeth come in between 6 and 8 months. By the age of 6, milk teeth are gradually replaced by permanent teeth. ▸ Hardest part in the body is tooth enamel. ▸ In elephants, the tusks are the incisors of upper jaw. ▸ Maximum number of teeth are present in horse and pig. Dental Formulae of Some Mammals
Man (child)
2102/2102 × 2
20
Man (adult)
2123/2123 × 2
Horse
3143/3143 × 2
44
Dog
3142/3143 × 2
Cow and Sheep
0033/3133 × 2
Cat
3131/3121 × 2
Rabbit
2033/1023 × 2
Mouse
1003/1003 × 2
▸ Saliva, secreted by the salivary glands, is mixed with the chewed food by the tongue. ▸ Tongue also contains taste buds due to which we sense bitter, sour, salty or sweet taste.
Splitting of complex food materials into simpler molecules by hydrolysis so that they can be easily absorbed by the intestine is the main function of digestive system. ▸ Man and other animals have holozoic nutrition i.e., solid form of food. Complete digestion process takes place in following four steps
▸ Ingestion takes place in buccal cavity. ▸ Saliva lubricates the food and binds the food particles together to form bolus. ▸ Salivary gland have starch spitting enzyme ptyalin. ▸ Parotid gland is the largest salivary gland.
Digestion in Mouth In mouth, salivary amylase acts on starch. Starch (Complex form) Maltose (Simple Ptyalin ––→ form) Digestion in Stomach ▸ The food passes down through the oesophagus into stomach. ▸ Now food is mixed with gastric juice and hydrochloric acid which disinfect the food and creates acidic medium. ▸ Pepsin digests proteins and converts them into peptones. ▸ Rennin convert milk into curd. ▸ Digested food now is called chyme. Digestion in Duodenum ▸ Chyme moves to duodenum. ▸ Food is mixed with bile (liver) to breakdown fats into smaller globules. ▸ Trypsin acts upon proteins and break them into polypeptides. Amylase converts starch into simple sugar. ▸ Lipase convert fats into fatty acids and glycerol. Digestion in Intestine ▸ Food passes into ileum and mixes with intestinal juice, where ▸ Maltase converts maltose into glucose ▸ Lactase converts lactose into glucose and galactose ▸ Sucrase converts sucrose into glucose and fructose ▸ Trypsin digests the peptides into amino acids Absorption and Assimilation of Digested Food ▸ Ileum's internal surface has finger-like folds called villi. ▸ It helps in absorption of food. ▸ Intestinal juice is alkaline in nature. ▸ pH of saliva, gastric juice, pancreatic juice and intestinal juice is respectively 6.8, 2.0, 7.0 and 8.5.
▸ Digested food passes into large intestine. ▸ Large intestine cannot absorb food, but absorbs much of the water. ▸ The remaining semi solid waste is called faeces and is passed into rectum. ▸ It is expelled out through anus.
▸ Roughage is another term for dietary fibres e.g., Natural food, dalia etc. ▸ It does not provide energy but only helps in retaining water in the body.
▸ It is the largest gland of the human body and secretes bile juice, which is stored in gall bladder. ▸ It regulates the quantity of glucose in the blood by converting extra glucose (if any) into glycogen or glycogen (during deficiency of glucose) is converted into glucose. ▸ It destroys dead RBC and regulates body temperature. It converts excess of amino acid into ammonia (which is converted into urea by Ornithine cycle). Urea comes out from the body through kidney. ▸ If there is any obstruction in bile duct, liver cells stop taking bilirubin from the blood, consequently it spreads throughout the body which is called jaundice. ▸ Liver is an important body organ in investigation of a person's death that has been due to poison in food.
▸ It is the second-largest gland of the human body and contains islets of Langerhans and exocrine part secreting enzymes for carbohydrate, protein and nucleic acid digestion. ▸ The most common is the β-cells, which secretes insulin, a hormone deficiency of which causes diabetes melitus. ▸ Excess of insulin causes hypoglyaemia, in which one loses the reproducing capacity and vision.
Crypts of Lieberkuhn and Brunner's glands are intestinal glands and secrete intestinal juice which is alkaline in nature.
Respiration is a catabolic process in which the respired oxygen is used in the oxidation of food resulting in the release of energy. It is brought about by respiratory organs. Respiratory Organs of Some Animals
Lungs
Reptiles like lizards, mammals like man, camel, cattle, etc.
Skin
Frog, earthworm and leeches
Gills
Fishes, tadpoles and prawns
Trachea
Insects, centipedes and millipedes.
Body surface
Amoeba, Euglena, Chlamydomonas, Spirogyra, Hydra, etc.
Book lungs
Spider, scorpion, ticks and mites.
Book gills
King crab, prawn, cray fish and Daphnia.
Air bladder
Lung fish and bony fishes(e.g., Labeo).
Air sacs/lungs
Birds
▸ Overall passage of air in humans is as follows: Nostrils→ Pharynx→ Larynx→ Trachea → Bronchi → Bronchioles → Alveoli → Cells→Blood. ▸ The human respiratory system is shown in the following diagram.
▸ The respiration taking place in the presence of oxygen is known as aerobic respiration. ▸ This respiratory oxygen oxidises the substance into carbon dioxide, water and energy, as follows Glucose + O2 ––→Carbon dioxide +Water + Energy. ▸ In this process, each glucose molecule is converted into two molecules of pyruvic acid by the process, called glycolysis. It takes place in the cytoplasm of the cell. The pyruvic acid formed, releases energy with the formation of carbon dioxide and water (in Kreb's cycle which occur in mitochondria).
▸ The respiration taking place in the absence of oxygen is known as anaerobic respiration. ▸ It is found in endoparasites like roundworm. In this process, the respiratory substances are incompletely oxidised to carbon dioxide and alcohol. Glucose ––→ yeast Carbon dioxide + ethyl alcohol muscles +Energy (in plants) Glucose ––→ Lactic acid + Energy (in animals)
▸ It involves inspiration and expiration of air. ▸ Inspiration is the process of intake of air. During inspiration, muscles of the diaphragm contract and diaphragm flattens. ▸ The lower ribs are raised upward and outwards. The chest cavity enlarges, the air pressure in the lungs gets decreased and air rushes into the lungs. ▸ Expiration is breathing out of air. During expiration, relaxation of muscles of the ribs and diaphragm takes place. ▸ Diaphragm again become dome-shaped. Chest cavity is reduced and air is forced outwards through nose and trachea. ▸ Breathing rate in humans is 18 – 20 times per min. ▸ The exchange of gases, i.e., oxygen and carbon dioxide takes place due to the difference in their partial pressures.
▸ It is a complex process in which food is broken down to release energy. ▸ Transportation of oxygen takes place by haemoglobin of blood. Whereas transportation of only 10-20% carbon dioxide takes place by haemoglobin of blood. ▸ Approximately 400 ml water is lost through breathing everyday. ▸ Respiration being a catalytic process, also reduces the weight of the body. ▸ Larynx or voice box or Adam's apple produces sound. It has a small flap of cartilage called the epiglottis, which prevents the food from entering the trachea. ▸ Purring sound in cats is due to the vibration of false vocal cord. ▸ In hippopotamus, true vocal cord is absent. ▸ Total Lung Capacity (TLC) = 6000 mL ▸ Residual Volume (RV) = 1200 mL ▸ Tidal Volume (TV) = 500-600 ml
▸ It is a transport system that supplies the useful material and removes the waste from the body cells. It consists of heart, blood vessels and blood.
▸ Heart is a thick, muscular, contractile, automatic pumping organ of blood vascular system. ▸ The chamber which receives the blood from body tissues are called auricles and the chambers of heart which pump blood to body tissues are called ventricles. ▸ There is a thin two layered sac around the heart known as pericardium, filled with a watery fluid called pericardial fluid, which allows frictionless movements of heart and protects it from mechanical shocks. ▸ Fishes have only two-chambered heart (one auricle and one ventricle). ▸ In amphibians, heart is three-chambered. ▸ In crocodile, birds and mammals, the heart is divided into four chambers (two auricles and two ventricles). ▸ Reptilian heart is structurally threechambered but is functionally fourchambered (i.e., incomplete fourchambered) except in crocodile. ▸ A new born baby's heart weight is about 20 g. ▸ The average weight of heart in men is 280-340 g, while in women is 230-280 g.
Diseases of Heart
Tachycardia
Increased rate of heartbeat.
Bradycardia
Decreased rate of heartbeat.
Heart attack
Breathlessness, palpitations, pain in the chest, unconsciousness appear suddenly (Nitroglycerine is used for the treatment).
Heart block
When heart beat is not passed to the ventricles properly. This is the defect of conducting system of the heart.
Coronary thrombosis
Due to the formation of clot in coronary artery.
Myocardial infarction
It is the death of a part of heart muscle following cessation of blood supply to it. It is acute heart attack.
▸ The circulation of blood through the whole body can be shown as ▸ To pump out blood, the heart chamber undergoes alternate contraction called systole and relaxation called diastole. The regular sequence of these systole and diastole causes the heart sound Lub and Dub. ▸ Arteries carry pure blood from the heart while veins carry impure blood to the heart. ▸ Human heart beat is myogenic in nature, i.e., initiated by a patch of modified heart muscles itself without requiring an external stimulation. This patch is called SA node (sino-auricular node) or pacemaker. ▸ When SA-node becomes defective, i.e., it does not generate cardiac impulses, it can be cured by surgical grafting of an artificial pacemaker (an electric device) in the chest of the patient. It stimulate the heart electrically at regular intervals. ▸ The normal rate of heartbeat at rest is about 70-72 times per minute. In a newly born baby, heartbeat rate is about 140 per minute. ▸ During heavy exercise it may be high as 170-200 times per minute.
▸ Blood is a fluid connective tissue and composed of blood corpuscles, plasma and platelets. ▸ It is slightly alkaline is nature (pH 7.4). ▸ Its volume in an adult is 5.8 L. ▸ The oxygenated or pure blood is bright red while the deoxygenated blood is purple coloured (Darker shade of red). ▸ People who live at high altitudes have more blood than those who live in low regions. This extra blood supplies additional oxygen to body cells. ▸ During blood clotting fibrinogen changes into fibrin by thrombin which is obtained from thromboplastin in the presence of Ca2+. ▸ The haemoglobin content of adult female varies from 13.5-14.5% whereas in adult male its amount varies from 14.5-15.5% Haemoglobin count is highest in the foetus and is about 23 g per 100 mL of blood at birth.
Blood vessels are of three types
▸ These are thick walled blood vessels which carry the blood away from the heart to various body parts. These are deep seated in the body and have no valves in them. ▸ These carry oxygenated blood except the pulmonary artery which carries deoxygenated blood to the lungs. In arteries, blood flows at a high pressure and a higher speed.
▸ These are thin walled blood vessels and carry blood away from various body parts towards the heart. These have valves in them to prevent back flow of blood in them. Blood flows at low pressure and at a lower speed. ▸ These carry deoxygenated blood except the pulmonary vein which carries oxygenated blood to the heart.
▸ These are the thinnest blood vessels and connect arteries to the veins. ▸ These help in exchange of materials like the nutrients, gases, waste products etc., between blood and cells.
Blood Type of Parent and their Children
O × O
O
O × A
O, A
O × B
O, B
O × AB
A, B
A × A
A, O
A × B
O, A, B, AB
A × AB
A, B, AB
B × B
B, O
B × AB
AB × AB
Erythrocytes (RBCs) ▸ Red blood cells contain the blood's haemoglobin and distribute oxygen. ▸ RBCs are the most abundant cells. ▸ Mature red blood cells lack a nucleus and organelles in mammals. However, in camel and llama it is nucleated. ▸ One RBC contains about 280 haemoglobin molecules.
These are part of the body's immune system; they destroy and remove old or aberrant cells and cellular debris, as well as attack infectious agents and foreign substances. These are much less in number than RBCs (1 : 600).
It is responsible for blood clotting (coagulation). It changes fibrinogen into fibrin.
▸ The pressure created by the blood on the walls of the blood vessels due to the repeated pumping of heart is called blood pressure. It is measured by sphygmomanometer. ▸ It can be felt at certain places in our body viz, wrist of the hands etc. ▸ Blood pressure is recorded as systolic/diastolic. Blood pressure in a normal person is 120 / 80 mmHg. Factors affecting blood pressure are age, cardiac output, total peripheral resistance etc. ▸ If a person has persistent high blood pressure then it is called hypertension and persistent high blood pressure is 150/90 mm Hg. Factors responsible are over eating, fear, worry, anxiety, sorrow etc. Hypotension is condition of low blood pressure, i.e., persistent 100/50 mm Hg. ▸ Electrocardiograph (ECG) is used to check proper working of heart by using electrodes. Comparison between Plasma and Lymph
It contains 92% water, 8% blood plasma proteins and trace amounts of other materials
Lymph contains a variety of substances including proteins, salts, glucose, fats, water and WBCs.
It is cell free part of blood, contain salts, considerable amount of proteins as well as more or less all constituents of body.
It is modified tissue fluid, contains cells like lymphocyte and monocytes, salt and small amount of proteins. It is colourless.
It flows within blood vessels.
It flows within lymphatic vessels.
It takes part in nutrition, excretion, respiration, etc., by transporting various materials and helps in the defence mechanism of the body by producing antibodies.
It supplies nutrition to tissue devoid of blood supply, takes part in fat absorption and defence mechanism of the body.
It can coagulate because it contains fibrinogen and prothrombin.
It can coagulate but very slowly because it contains these two in small quantities.
The human skeleton consists of both fused and individual bones supported and supplemented by ligaments, tendons, muscles and cartilage. It is divided into two parts
▸ It includes skull, vertebral column and bones of chest (ribs and sternum). ▸ Vertebral column is responsible for the upright position of the human body. ▸ Most of the body weight is located at the back of the vertebral column. It provides flexibility to the neck and protection to spinal cord.
Their function is to make locomotion possible and to protect the major organs of locomotion, digestion, excretion and reproduction. Important Bones in the Body
Skull (29)
Facial
14
Cranium
Hyoid
Ear ossicles (maleus, Incus, stapes)
Vertebral column(26) (Note-The total number of bones in vertebral column, initially is 33 and after development, it reduces to 26)
Cervical
Thoracic Lumbar Sacrum Coccyx
12 5 1(5) 1(4)
Bones of chest (25)
Sternum
Ribs
24 (12 pairs)
Shoulder (Pectoral girdle)
Scapula Clavicle
Upper arm
Humerus
Fore arm
Radius-ulna
Wrist
Carpals
Palm
Metacarpals
Fingers
Phalanges
Hips (Pelvic girdle)
Ilium, ischium, Pubis (Innominate)
Thigh
Femur
Knee
Patella
Shank
Tibia-Fibula
Ankle
Tarsal
Sole
Metatarsal
Toes
The structural arrangements of tissues by which bone and bone or bone and cartilage joined together. They are of following types
Immovable
Bones of skull
Slightly movable
Pubic bones of pelvic girdle
Hinge
Ankle, Knee, elbow
Ball and Socket
Shoulder and hip
Pivot
Radius and humerus
Saddle
Metacarpal and carpal
Gliding
Vertebra, radio-ulna and carpals
▸ Tendons join the muscles and bones. ▸ The muscles which join bone to bone are called ligaments.
▸ Hard tissue deposits over articular cartilage along with higher secretion of synovial fluid causing pain and stiffness lead to rheumatoid arthritis. (An auto immune disease). ▸ Tearing of articular cartilage and development of bony lumps at places causing pain, stiffness and permanent bending lead to osteoarthritis. ▸ Osteoporosis is loss of bone density due to excessive absorption of calcium and phosphorus from the bone. ▸ Osteopetrosis is a hereditary disease marked by abnormally dense bone and by the common occurrence of fractures of affected bone. ▸ Birds have spongy bones with air filled spaces, called pneumatic bones. ▸ Rigor mortis is the state of body stiffening after death. ▸ Chronic fatigue is the inability of a muscle to contract due to depletion of its chemicals and lactic acid accumulation by repeated contraction. A completely fatigued muscle refuses to respond to nervous stimuli.
▸ Human body has about 639 types of muscles. ▸ Muscles specialised to contraction are of three types, i.e., striated, unstriated and cardiac. ▸ Striated muscles Also called skeletal muscles or voluntary muscles. They are present in limbs, tongue, pharynx etc. ▸ Unstriated muscles These are involuntary muscles and present in urinary bladder, in walls of large blood vessels and alimentary canal. ▸ Cardiac muscles They are involuntary, striated and non-fatigued fibres which are found in the wall of heart, where they form myocardium. They generate their own wave of excitation.
The process of removal of nitrogenous wastes from the body is called excretion. The organs of excretion are called excretory organs. Excretory Organs of Some Animals
Contractile vacuole
Amoeba
Flame cells/solenocytes
Tapeworm
Renette cell
Ascaris
Nephridia
Earthworm
Malpighian tubules
Cockroach
Coxal glands
Scorpion
Green glands
Prawn
Ammonotelic Animals These animal excrete nitrogen in the form of ammonia, e.g., aquatic invertebrates Amoeba, Hydra, Prawn, Pila, and freshwater fishes, bony fishes, Frog's tadpole. Ureotelic Animals They excrete nitrogen in the form of urea, e.g., mammal (man), frogs, toads, other amphibians and cartilaginous fishes like sharks. Uricotelic Animals They excrete the nitrogenous wastes in the form of uric acid, e.g., Reptiles, snakes, lizards, crocodiles and birds. Human Excretory System The human excretory system includes—the kidneys (two), ureters (two), urinary bladder (one) and urethra (one). Kidney ▸ It is bean-shaped, chocolate brown organ lying in the abdomen, one on each side of the vertebral column just below the diaphragm. ▸ The left kidney is placed a little higher than the right kidney (but reverse in rabbit). ▸ These form the urine and controls osmotic pressure within the organism with respect to external environment. ▸ Nephrons are the functional and structural unit of kidney. Each nephron is made up of Bowman's capsule and renal tubule. Renal tubule is made up of Proximal Convolutid Tubule (PCT), Henle's loop, Distal Convoluted Tubule (DCT) and Collecting Tubule (CT). Ureters These bring the urine downward and open into urinary bladder. Urinary Bladder ▸ It temporarily stores the urine. ▸ It can hold about 0.5-1.0 L of urine. ▸ It is absent in birds. In both reptiles and birds, ureters and rectum, opens into a common sac called cloaca. Urethra ▸ It is a muscular and tubular structure which extends from neck of bladder to outside. In females, this tube is small and serves as a passage of urine only. ▸ In males, it is long and functions as a common passage for urine and spermatic fluids. Urine ▸ It is a pale yellow coloured fluid due to presence of urochrome pigment. ▸ It is acidic in nature (pH 6.0) and is slightly heavier than water. ▸ It has a faint aromatic odour due to urinoid. Daily urine output in normal adult is 1.5-1.8 L. ▸ Chemical composition of urine : water is 95-96%, urea is 2% and some other substance like uric acid, creatinine, etc., are 2-3%. ▸ The urine on standing gives a pungent smell. It is due to conversion of urea into ammonia by bacteria. ▸ Haemodialysis is the process of removal of excesss urea from the blood of patient using artificial kidney. ▸ Kidney stone are generally calcium oxalate crystals.
▸ The nervous system provides the fastest means of communication within the body so that suitable response to stimuli can be made at once. ▸ Nervous system is found only in animals and absent in plants. ▸ In most animals, the nervous system consists of two parts—central and peripheral nervous system.
Brain ▸ Brain lies in the cranium of skull. ▸ Cerebrospinal fluid is present in brain and spinal cord. The functions of brain parts are as follows Forebrain ▸ Cerebrum leads to consciousness, storage of memory having information. ▸ Thalamus deals with touch, visual system, sleep and wakefulness. ▸ Hypothalamus deals with water balance in body, behavioral patterns of sex, sleep, stress emotions etc. It also regulates pituitary hormones and metabolism of fat, carbohydrate water and maintain body temperature (homeostasis). Midbrain It deals with visual analysis, auditory etc. Broca's area is present in brain and is related with speech production, while Wernick's area of brain is related with understanding of speech. Hindbrain ▸ Cerebellum controls coordination of accurate movements and balancing. ▸ Medulla oblongata is long connecting part of brain to spinal cord. It deals with control of heart beats, blood vessels, breathing, salivary secretion and mostly reflex and involuntary (uncontrolled) movements. Nobel Prize in Medicine 2016 The Nobel Prize in physiology or medicine 2016 was awarded to Yoshinori Ohsumi 'for his discoveries of mechanisms for autophagy. The word 'autophagy' originates from the Greek words auto, meaning 'self and phageil meaning to 'eat'. It is an evolutionarily conserved process in which the eukaryotic cell can recycle part of its own content.
Deals with impulses to and from the brain and is the centre for reflex actions like blinking of the eye when an object comes near to our eyes suddenly, rapid withdrawal of hand while coming near to heat, knee jerk reflex etc. Acquired reflex action is also called conditioned reflex as dependent on past experience, training and learning. It was first demonstrated by Ivan Petrovich Pavlov e.g. learning, dancing, cycling, swimming, singing and driving etc are controlled by spinal chord. It is under cerebral control during learning.
▸ It is a collective term for the nervous system structures that do not lie within the CNS. ▸ It is composed of cranial and spinal nerves. There are 10 pairs of cranial nerves in fishes and amphibians and 12 pairs in rest of the higher chordates. ▸ There are 10 pairs of spinal nerves found in fishes and amphibians and 31 pairs in humans. ▸ The PNS is divided into two divisions: Somatic Nervous System (SNS) and Autonomous Nervous System (ANS). ▸ It is a part of peripheral nervous system that relays impulses from the CNS to skeletal muscles.
It is also a part of peripheral nervous system that transmits impulses from the CNS to involuntary organs and smooth muscles of the body. Autonomic nervous system consists of two divisions 1. Sympathetic Nervous System increases defence system of body against adverse conditions. It is active in stress condition, e.g., pain, fear and anger. 2. Parasympathetic Nervous System provides relaxation, comfort, pleasure at the time of rest. It helps in the restoration and conservation of energy. ▸ Electroencephalogram (EEG) is a test that measures and records the electrical activity of our brain.
Eyes are the sensitive detectors of light. The human eye can distinguish about 10million colours. It consists of three parts
It is the outermost, bony layer, which includes ▸ Cornea the clear, dome-shaped tissue, covering the front of the eye. ▸ Conjunctiva, the continuation of upper eyelid.
It is the middle layer and consists of 1. Pupil is the black hole in the centre of the iris. It changes size as the amount of light changes. 2. Ciliary muscles regulates the lens curvature. 3. Iris is the coloured part of the eye. It controls the amount of light that enters the eye by changing the size of the pupil. 4. Lens is a biconvex transparent circular solid located just behind the iris. It focuses light onto the retina.
▸ Light sensitive tissue that lies at the back of the eye. It contains millions of photoreceptors (rods and cones) that convert light rays into electrical impulses that are relayed to the brain via the optic nerve. ▸ The image formed on retina is real and inverted. ▸ Rods are highly sensitive to dim light and contain a reddish purple pigment called rhodopsin. Night vision involves mostly rods (not cones). ▸ Cones are sensitive to bright light, hence differentiate the colours. ▸ The fovea centralis is the area of sharpest vision due to high concentration of cones. ▸ The blind spot (optic disc) has no rods and cone cells, hence no image is form in this region.
Nearsightedness (Myopia) ▸ A condition in which nearby objects are seen more clearly than distant objects because light is focused in front of the retina, not on it. It can be corrected by using concave glasses. Farsightedness (Hypermetropia) ▸ A condition in which distant objects are seen more clearly than nearby objects because light is focused behind the retina, not on it. ▸ It can be corrected by using convex glasses. Astigmatism ▸ A condition in which the lens is warped, causing images not to focus properly on the retina. ▸ The cylindrical glass can correct the defect. ▸ Colour blindness also called Daltonism is caused due to deficiency of cones. While night blindness is due to deficiency of rhodopsin in rods. ▸ Retina of Owl contains only rods while fowl contains only cones. ▸ The eyes of carnivores like cat, dog, iron sea etc, glow in night due to tapetum lucidum. Eyes are most sensitive to yellow green colour. Bees can see ultraviolet light. Presbyopia ▸ It is a reduction in pupil size and the loss of accommodation or focusing capability with age, leading to a substantial decrease in light received at the retina. ▸ Bifocal lens can correct the defect. ▸ Conjunctivitis is an inflammation of conjunctiva by bacteria. Correspondence between Camera and Eye
Box
Sclera
Black inner paint
Choroid
Shutter
Eye lids
Diaphragm
Iris
Light hold
Pupil
Lens
Light sensitive film plate
Retina
▸ Ears are meant for both balancing and hearing. ▸ It can be divided into three parts as External ear (pinna + external auditory canal), Middle ear (tympanic cavity) and Internal ear (bony and membranous labyrinth). ▸ Hearing is controlled by auditory area of temporal lobe of cerebral cortex. ▸ Human ear can receive the sound ranging between 60-80 decibel. ▸ Human ear is sensitive to sounds frequency 50-20,000 cycles/sec. ▸ Defects of ear are : Otalgia ear, ache (Pain in ear); Othitis media (Acute infection of middle ear) Labyrithine disease (malfunction of inner ear).
▸ Nose is a sense organ for smell or olfaction. It contains 1. Olfactory cells which are more chemosensitive than taste cells. 2. Olfactory stimuli such as, chloroform and ammonia are irritating and can cause tearing. ▸ Dogs have an acute olfactory sense. They can trace people because they can distinguish between the odours of different persons.
▸ The process by which new individuals are produced from their parents is called reproduction and the organs which are used for this process, collectively constitute the reproductive system. ▸ Reproduction is of two types, i.e., asexual and sexual. ▸ In asexual reproduction, only one parent is involved and sex cells are not involved. ▸ In sexual reproduction, two parents are involved and formation and fusion of gametes takes place. Modes of Reproduction in Different Organisms
Fission (asexual)
Amoeba, bacteria, flatworm etc.
Budding (asexual)
Hydra, yeast and sponge etc.
Syngamy (sexual)
Cockroach, frog and human being etc.
▸ The various organs which constitute the male reproductive system and their functions are tabulated below:
Testes
2
Produce sperm and testosterone
Sperm duct
Conduct the sperm from the testes to urethra
Seminal vesicles
Secrete seminal plasma
Epididymis
Temporarily store sperm and provides mobility.
Urethra
Conduct urine and sperms.
Prostate gland
Secrete an alkaline fluid to neutralise the acidity of urethra and make the sperm more active.
Cowper's gland
Secrete an alkaline white lubricating fluid.
Penis (have rich blood supply)
Pass urine and deposit sperm in female genital tract.
▸ Males can produce spermatozoa (sperm) throughout their life from age of 13-14 years. The growth of hairs on body is due to masculine hormones.
Female reproductive system includes following organs which are tabulated below
Ovaries
To produce ova and hormones.
Oviducts
To move the ovum towards uterus.
Uterus
To provide space for developing child.
Vagina
To receive the sperms.
▸ If sperm is present, the egg will be fertilised in the ampullary isthmic junction of Fallopian tube.
Female Reproductive System ▸ After maturity the ovary releases an ovum (egg cell) after every 28 days. ▸ The connection between developing embryo and mother is made by placenta. It supplies blood, organic and inorganic nutrients, hormones, antibodies etc. ▸ The embryo develops for nine months in uterus. It is called gestation period. ▸ Child is delivered after its development and mother produces milk to nourish the child (lactation). ▸ The first milk which comes out from the mother's mammary gland just after child birth is called colostrum. ▸ This milk is rich in protein, antibodies which imparts immunity to new born baby.
▸ Reproductive period of a human female extends from puberty (10-14 years) to menopause (40-50 years). ▸ The release of the first menstrual flow or period is called menarche. ▸ Menarche marks the onset of reproductive life and onset of puberty in females. ▸ Menopause is stopping of ovulation and menses. It normally occurs between the age of 45 to 55. This stage onwards, woman lose the ability to reproduce. ▸ The periodic vaginal bleeding during menstrual cycle is called menstruation. ▸ On an average menstural cycle is completed in 28 days. ▸ It is absent during pregnancy, may be suppressed during lactation and permanently stops at menopause. About 13 mature eggs are released from two ovaries of female in a year. ▸ Menstrual cycle is controlled by FSH, LH, oestrogen and progesterone hormones.
▸ The prevention of union of sperm and ovum is known as contraception. The various methods used for it are diaphragm, contraceptive pills, tubectomy, vesectomy, copper-T etc. ▸ Amniocentesis or amniotic fluid test is technique of finding out sex and disorder of foetus. Gestation Periods of Some Animals
Buffalo
310 days
340 days
Elephant
610 days
Leopard
105 days
Lion
120 days
Tiger
103 days
Whale
365 days
Squirrel
40 days
▸ It includes endocrine or ductless glands. Their secretion is known as hormones. ▸ Different types of hormones are ▸ Steroids, e.g., oestradiol, testosterone, androsterone, aldosterone, cortisol and cortisone. ▸ Peptides, e.g., insulin, glucagon, pituitary hormones, parathormone and relaxin. ▸ Amino acid derivatives, e.g., adrenaline, noradrenaline and thyroid hormones. Various glands are:
It is a part of forebrain and regulates the pituitary glands and maintains body temperature (homeostasis).
▸ It governs other endocrine glands like thyroid, adrenal and gonads. ▸ Pituitary gland is also known as master gland.
▸ It is the largest endocrine gland and located in neck region. ▸ It is the 'pace setter' of the endocrine system. It secretes 1. Thyroxine, which regulates BMR (Basal Metabolic Rate), physical, mental and sexual development. 2. Thyrocalcitonin secreted by the C-cells and regulates the calcium homeostasis (lowers calcium level).
It is both an exocrine and endocrine gland. The islet of Langerhans (endocrine) have three major types of cells 1. Alpha-Cells secretes glucagon hormone which increases blood sugar level. 2. Beta-Cells secretes insulin, which decreases the amount of sugar in the blood. 3. Delta-Cells secretes somatostatin which is an anti-growth factor.
▸ It is also known as emergency gland. (a) Cortex (outer layer) (b) Medulla (inner layer) It secretes two important hormones— Epinephrine or adrenaline and nor-epinephrine or noradrenaline ▸ It increases the blood glucose level, blood pressure and cardiac output.
▸ It is situated in the brain and also known as clockwork gland. ▸ It regulates the ovaries and has an effect on the biological rhythm.
These secrete steroid hormones.
It helps in the development of primary and secondary sexual characters (oestradiol, oestriol and estrogen). Hypersecretion of androgenic steroids in female results in stopping of menstruation, hairs on face and breasts.
These are produced by Leydig cells of testes.It stimulate growth, maturation and maintenance of male gonads and development of secondary sexual characters, e.g., testosterone, androsterone etc.
Health is the functional or metabolic efficiency of a living being. In human, it is the general condition of a person's mind, body and spirit, usual meaning, to be free from illness, injury or pain.
It is a condition of the body or its part in which functions are disturbed. The diseases may be broadly classified into two types, i.e., congenital and acquired.
These are anatomical or physiological abnormalities present from birth. They may be caused by ▸ A single gene mutation (alkaptonuria, phenylketonuria, albinism, sickle-cell anaemia, haemophilia and colour blindness). ▸ Chromosomal aberrations (Down's syndrome, Klinefelter's syndrome and Turner's syndrome). ▸ Environmental factors (cleft palate and harelip). Unlike the gene and chromosome induced congenital defects, environmentally caused abnormalities are not transmitted to the children.
These diseases develop after birth. They are further of two types, i.e., communicable and non-communicable. 1. Communicable (infectious) diseases are caused by pathogenic micro-organisms, such as bacteria, viruses, parasites or fungi; the diseases can be spread, directly or indirectly, from one person to another. Infectious diseases, are also known as transmissible diseases. 2. Non-communicable (noninfectious) diseases are not passed by organisms among people, but come from genetic or lifestyle factors.
These are the diseases which may pass or carried from one human or animal to other. Communicable diseases are illness caused by germs such as bacteria, viruses and spread by an infected person, animals or object to other persons.
Viruses are parasitic and causes a number of diseases. Bird Flu(H5 N 1) Bird flu (Avian influenza) is a disease caused by an influenza virus-A, that primarily affect birds. The following persons may be on higher risk for developing the bird flu ▸ Farmers and others, who work with poultry. ▸ Travellers, visiting affected countries. ▸ Those who have touched an infected bird. ▸ Those who eat raw or undercooked poultry meat, eggs from infected birds. Symptoms Fever, cough, sore throat, muscle aches and eye infection (conjunctivitis). Treatment Treatment with the antiviral medication oseltamivir (tamiflu) or zanamivir (relenza) may make the disease less severe. Oseltamivir may also be prescribed for persons, who live in the same house as those diagnosed with avian flu.
It is a serious form of pneumonia. It is caused by a virus that was first identified in 2003. Infection with the SARS virus causes acute respiratory distress (severe breathing difficulty) and sometimes death. Symptoms Cough usually starts 2-3 days after other symptoms like Fever, headache and muscle aches. Treatment Antibiotics to treat bacteria that cause pneumonia. Antiviral medications. High doses of steroids to reduce swelling in the lungs. Oxygen, breathing support (mechanical ventilation) or chest therapy.
Hepatitis is a swelling and inflammation of the liver. It is not a condition, but is often used to refer a viral infection of the liver. Hepatitis can be caused by ▸ Immune cells in the body attacking the liver and causing autoimmune hepatitis. Infections from viruses (such as hepatitis-A, B or C), bacteria or parasites. Liver damage from alcohol, poisonous mushrooms or other poisons. ▸ Medications, such as an overdose of acetaminophen, can cause harm or death also. Symptoms Abdominal pain or distention. Breasts development in males. Dark urine and pale or clay coloured stools. Fatigue, general itching, fever, usually low-grade jaundice (yellowing of the skin or eyes) and loss of appetite, nausea, vomiting and weight loss.
Acquired Immuno Deficiency Syndrome (AIDS) is a disease of the human immune system caused by the Human Immunodeficiency Virus (HIV). AIDS was first recognised by the Centres for Disease Control and Prevention (CDC) in 1981. HIV Infection AIDS is a condition caused by HIV infection. The condition gradually destroys the immune system, which makes it harder for the body to fight infections. Transmission HIV can be spread by the following ▸ Through sexual contact i.e. oral, vaginal and anal sex. ▸ Through blood transfusions, accidental needle sticks or needle sharing. ▸ From mother to child: A pregnant woman can transmit virus to her foetus through their shared blood circulation or a nursing mother can pass it to her baby through breast's milk. Test for AIDS ▸ Enzyme Linked Immunosorbent Assay/ Enzyme Immuno Assay (ELISA/EIA) ▸ Radio Immuno Precipitation Assay/ Indirect Fluorescent Antibody Assay (RIP/IFA) ▸ Polymerase Chain Reaction (PCR) ▸ Western Blot Confirmatory Test.
There are various kinds of non-communicable diseases, which affect the health of human beings. Some of the common non- communicable diseases are
Diabetes is a long-termcondition caused by too much glucose (sugar) in the blood. There are two main types of diabetes Type 1 Diabetes occurs when the body doesn't produce enough insulin to function properly or the body's cells don't react to insulin. This is known as insulin resistance. Type 2 Diabetes is far more common than type 1 diabetes, which occurs when the body doesn't produce any insulin at all. Symptoms Symptoms common to both types of diabetes include (i) Feeling very thirsty. (ii) Urinating frequently, particularly at night. (iii) Feeling very tired. (iv) Weight loss and loss of muscle bulk.
It is uncontrolled growth of abnormal cells in the body. Some diseases cause emergence of tumours in body. These are called neoplastic diseases. This includes from a minor role to a lethal cancer. Causes of Cancer ▸ Cancer is induced by physical, chemical and biological factors or agents. These are called carcinogens or cancer causing agents. Ionising radiations such as X-rays, γ-rays and non-ionising radiations such as ultraviolet (UV) damage the DNA leading to neoplastic transformation. ▸ Tobacco smoke contains chemical carcinogens that causes lung cancer. Viruses also cause cancer. These are called oncogenic viruses as they have genes called viral oncogenes. Cancer Detection and Diagnosis Leukaemia or blood cancer can be detected based on biopsy and histopathological studies of the tissue and blood and bone marrow tests for increased cell counts. Cancers of internal organs are detected using techniques such as Radiography Computed Tomography (RCT) and Magnetic Resonance Imaging (MRI). Cancer Therapy ▸ Cryo Surgery It is the technique of using extreme rapid cooling that freeze tissues, thereby destroy them. Rapid cooling to temperature below freezing point produces irreversible cell damage and cell death occurs at 20°C to –90°C. ▸ Proton Therapy It is a type of particle therapy, which uses a beam of protons to irradiate diseased tissue, most often in the treatment of cancer. ▸ Radiation Therapy Radiation therapy is a cancer treatment. Its goal is to kill cancer cells and shrink tumours. ▸ Stem Cell Transplantation Stem cell transplants can be an effective treatment for people with certain forms of cancer, such as leukaemia and lymphoma. ▸ Peripheral Blood Stem Cell Transplantation (PBSCT) It is also called peripheral stem cell support. This procedure restore stem cells that has been destroyed by high doses of chemotherapy.
Some heart diseases are as follow Angina Pectoris Human with angina, experience pain in the centre of the chest. The chest can feel constricted and tight, but the pain can also be oppressive, as if something is crushing your chest. Pain starts in the centre of the chest behind the breast bone (sternum) or on the left side of the front of the chest. It can spread out to other parts of your body like your arms and stomach. Myocardial Infarction ▸ It is commonly known as heart attack, results from the interruption of blood supply to a part of the heart, causing heart cells to die. ▸ This is most commonly due to occlusion (blockage) of a coronary artery following the rupture of a vulnerable atherosclerotic plaque, which is an unstable collection of lipids (cholesterol and fatty acids) and white blood cells (especially macrophages) in the wall of an artery. ▸ The result is ischemia (restriction in blood supply) and ensuing oxygen, if left untreated for a sufficient period of time, can cause damage or death (infarction) of heart muscle tissue (myocardium). Heart Arrest ▸ It occurs when the heart is unable to provide sufficient pump action to distribute blood flow to meet the needs of the body. Heart arrest can cause a number of symptoms including shortness of breath, leg swelling and exercise intolerance. ▸ The condition is diagnosed with echocardiography and blood tests. Treatment commonly consists of lifestyle measures such as smoking cessation, light exercise including breathing protocols, decreased salt intake and other dietary changes and medications.
▸ It affects the musculoskeletal system, specifically the joints. It is the main cause of disability among people over 55 years of age in industrialised countries. ▸ Rheumatoid Arthritis (RA) It is a long-term disease that leads to inflammation of the joints and surrounding tissues. It can also affect other organs. Osteoarthritis It is a joint inflammation that results from cartilage degeneration. It can be caused by ageing, heredity and injury from trauma or disease. The most common symptom of osteoarthritis is pain in the affected joint(s) after repetitive use. Gout Gout is a kind of arthritis. It can cause an attack of sudden burning pain, stiffness and swelling in a joint, usually a big toe. These attacks can happen over and over unless gout is treated. Overtime, they can harm your joints, tendons and other tissues. Gout is most common in men. SexuallyTransmittedDiseases ▸ Gonorrhoea It is caused by bacteria Neisseria gonorrhoeae. Anyone who has any type of sexual contact can catch gonorrhoea. The infection can be spread by contact with the mouth, vagina, penis or anus. ▸ Syphilis It is a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum sub-species pallidum. The primary route of transmission is through sexual contact; it may also be transmitted from mother to foetus during pregnancy or at birth, resulting in congenital syphilis. ▸ Genital herpes It is a Sexually Transmitted Infection (STI) caused by the Herpes Simplex Virus (HSV). ▸ Trichomoniasis It is a sexually transmitted infection caused by the parasite Trichomonas vaginalis.
A mental disorder or mental illness is a psychological pattern or anomali, potentially reflected in behaviour, that is generally associated with distress or disability and which is not considered part of normal development of a person's culture. This may be associated with particular regions or functions of the brain or rest of the nervous system, often in a social context. Alzheimer's Disease It is a progressive mental deterioration that can occur in middle or old age, due to generalised degeneration of the brain. It is the commonest cause of premature senility.
A drug is a substance, which when taken in, alters the body functions. Repeated use of drugs particularly for obtaining quick pleasure is called drug abuse.
Below are the types of simple drugs Analgesic (Pain Killers) These drugs act in various ways on the peripheral and central nervous system; they include paracetamol (acetaminophen), the non-steroidal anti-inflammatory drugs (NSAIDs) such as the salicylates, narcotic drugs such as morphine, synthetic drugs with narcotic properties such as tramadol and various others. Anaesthetic An anaesthetic is used to temporarily reduce or take away sensation, usually so that painful procedures or surgery can be performed. There are two types of anaesthetics ▸ General which make the patient unconscious. ▸ Local which numb the part of the body that would otherwise feel pain. Antibiotics (Bactericidal) These are powerful medicines that fight bacterial infections. When used properly, antibiotics can save lives. They either kill bacteria or stop them for reproducing. Antihistamines These are medicines that can be used to relieve severe itching and help in breaking histamine cycle. It leads to thickening and weeping of the skin and generally makes the eczema worse and more likely to become infected because scratching breaks the skin. Tranquiliser It is a drug that induces tranquility in an individual. The minor tranquilisers induce a feeling of calm and relaxation. Depending on the medication and dosage, this can range from feeling of mild euphoria to states of drowsiness, confusion and lightedness. Sedative It is a substance that induces sedation by reducing irritability or excitement. At higher doses it may result in slurred speech, staggering gait, poor judgment and slow, uncertain reflexes. Doses of sedatives such as benzodiazepines, when used as a hypnotic induce sleep, tend to be higher than amounts used to relieve anxiety, whereas only low doses are needed to provide a peaceful and calming sedative effect. Narcotic It is originally referred medically to any psychoactive compound with any sleep-inducing properties. Antipyretics (Temperature Reduction) These are drugs or herbs that reduce fever. Antipyretics cause the hypothalamus to over ride an interleukin-induced increase in temperature. The body then works to lower the temperature, resulting in a reduction of fever. ▸ Bacteria of cholera and TB was discovered by Robert Koch. Disorders Caused by Hormonal Irregularities Disorders Hormone Quantity Gland
Deficiency
Pituitary
Excess
Thyroid
Parathyroid
Adrenal cortex
Symptom
Tuberculosis
Diphtheria
Respiratory tract
Whooping cough or pertussis
Respiratory system
Cholera
Intestine
Leprosy or Hansen's disease
Chronic infection of skin and nerve
Tetanus (lock jaw)
Central nervous system
Pneumonia
Typhoid
Anthrax
Skin and intestine
Plague (i) Bubonic plague
Blood disease
(ii)Pneumonicplaque
(iii) Septicemic plague
Gonorrhoea (sexual disease)
Urinary tract
Viral Diseases in Human Beings Disease Pathogen Affected Part Symptom
Whole body
Loss of appetite, reddish eruption on the body.
High fever, reddish eruption on body.
Light fever, eruption of blood on body
Throat, backbone and nerve
Fever, backbone and intestine wall cells are destroyed. It leads to paralysis.
Inflammation of upper respiratory tract, nose throat and eyes.
Nervous system
Encephalitis, fear of water, high fever, headache, spasm of throat and chest leading to death.
Liver
Loss of appetite, nausea, whitish stool and jaundice.
(i) Hepatitis-A
Hepatitis-A virus
Not fatal
(ii) Hepatitis-B
Hepatitis-B virus
Fatal
Dengue fever
RNA containing dengue virus
Whole body, particularly head, eyes and joints
High fever, backache, headache, retro-orbital pain behind the eye ball.
AIDS (Acquired Immuno Deficiency Syndrome)
HIV (Human Immuno Deficiency Virus)
White blood cells
Weak immune system.
Herpes
Herpes virus
Swelling of skin.
Ebola virus disease
Ebola Virus (filovirus)
Fatal hemorrhagic fever, liver and kidney disfunction vomiting, headache.
Swine influenza (flu)
H N1 1 flu virus
Whole body (muscles)
Headache, tiredness, sore throat, Vomiting, breathing problems.
Protozoan Diseases, their Vectors and Affected Part
Disease
Pathogen (Causative agent)
Vector
Parts Affected and Symptoms
Pyorrhoea
Entamoeba gingivalis
None, infection by lip kissing.
Bleeding of gums.
African trypanosomiasis
Trypanosoma gambienes
Tse-tse fly (Glossina palpalis)
Blood and nervous tissue. Man feels sleepy, may cause death.
Amoebic dysentery (Amoebiasis)
Entamoeba histolytica
None, Infection by contamination.
Colon (intestine). Develop loose motion with blood, pain in abdomen
Diarrhoea
Giardia
None, infection by contamination
Digestive system causes loose motions, vomitting.
Kala azar or dumdum fever
Leishmania donovani
Sand flies (Phlebotomus)
Spleen and liver enlarge and high fever develops.
Filaria or elephantiasis
Wuchereria bancrofti
Culex mosquito
Swelling of legs, testes and other body parts.
Malaria
Plasmodium sp.
Female Anopheles mosquito
Periodical attacks of high fever, pain in joints accompanied by chill, heavy perspiration and fast pulse.
▸ Fishes like cat fish, Gambusia and aquatic birds eat mosquito larvae. ▸ Quinone, a product of Cinchona tree, is administered for malaria. Fungal Diseases in Human Beings Disease Pathogen (fungi) Symptoms
Asthma or aspergillosis
Aspergillus fumigatus
Obstruction in the functioning of lungs.
Athlete's foot
Tinea pedis
Skin disease, cracking of feet.
Scabies
Acarus scabiei
Skin itching and white spot on the skin.
Ringworm
Tricophyton Verrucosum
Round red spot on skin.
Baldness
Tinea capitis
Hair fall.
Some Immunological Tests and Diseases
Test
Ames test
Carcinogenecity
Widal test
Dick test
Scarlet fever
Wayson stain test
Plague
Montoux test
Tourniquet test
Rose-Waaler test
Rheumatoid fever
ELISA test
AIDS
Wassermann test
Syphilis
Some Viral Diseases in Animals
Animal
Cow
Variola vera
Small pox
Pox virido orthopox
Blue tongue virus
Blue tongue
Street rabies virus
Rabies
▸ It is the process of artificial introduction of germs or the germ substance called antigen into the body for developing resistance to a particular disease. The material introduced into the body is called vaccine. ▸ A vaccine is a dead or weakened microbes. They are unable to produce disease as they are less in number but they stimulate the body to produce antibodies. ▸ World Health Organisation (WHO) in 1974 officially launched a global vaccination programme to protect children from six fatal diseases. Diphtheria, pertussis, tetanus, polio, TB (Tuberculosis) and measles. It was launched in India in 1985. ▸ BCG (Bacillus Calmette Guerin) vaccine is given to protect against TB (Tuberculosis). ▸ DPT (diphtheria, Pertussis and Tetanus) vaccine is given to babies within first 6 weeks of their birth. Some Vaccines and their Doses
Birth to 12 months
DPT (triple vaccine, against diptheria, whooping cough/pertussis and tetanus) Polio (Sabin's oral, previously Salk's injectible) BCG (Bacillus Calmette Guerin)
Three doses (commonly oral) at intervals of 4-6 weeks. Three doses at intervals of 4-6 weeks. Intradermal and one vaccine
9-15 months
Measles vaccine (MMR or Measles, Mumps and Rubella)
One dose
8-24 months
DPT Polio (oral) Cholera vaccine (can be repeated every year before summer)
Booster dose Booster dose One
5-6 years
DT (Bivalent vaccine against diphtheria and tetanus) TAB (vaccine against Salmonella typhi, S. paratyphi A and S paratyphi B) or Typhoid Paratyphoid vaccine
Booster dose Two doses at intervals of 1-2 months
10 years
Tetanus, TAB (typhoid)
Booster dose
16 years
Tetanus, TAB
Human Body (At a Glance)
Total number of bones in the human body
206
Largest organ of human body
Number of cells in body
75 trillion
Longest bone
Femur (Thigh bone)
Smallest bone
Ear–ossicle and stapes
Weight of brain
1424 g
Blood volume
6.8 L (in 70 kg body)
Normal BP
120/80 mm Hg
Hb content in body
500-700 gm
Blood platelets
200000-400000 per cubic mm
Universal blood donor
O Rh–(ve)
Universal blood recipient
AB
Blood clotting time
2-5 minutes
Normal body temperatue
98.4° F or 37°C
Breathing rate
16-20/minute
Dental formula
Adult : 2123/2123 = 32 Child : 2120/2120 = 20 milk teeth
Largest endocrine gland
Largest muscle in the body
Gluteus maximus (Buttock muscle)
Greatest regeneration power
In liver
Menopause age
40-50 years
Minimum regeneration power
In brain cells
Minimum distance for proper vision
25 cm
Pulse rate
72/minute
Normal sperms count
200-350 million/ejaculation
ESR (Erythrocyte Sedimentation Rate)
4-10 min/h
Thinnest skin
Conjunctiva
It is the study of heredity and variations. The term 'Genetics' was coined by W Bateson in 1905. Gregor Johann Mondel (commonly called Father of Genetics) proposed three laws (a) Law of Dominance It states that crossing of plant with red and white flower produced plants only with red flower i.e., dominant trait appear and recessive disappeared. (b) Law of Segregation It states that allele of a gene separate during gamete formation. It is also called law of purity of genetics or law of splitting of hybrids. It gives 3 : 1 ratio in F2 generation. (c) Law of Independent Assortment It states that two or more genes assort independently during inheritance. It gives 9 : 3 : 3 : 1 ratio in F2 generation. Linkage is an exception to this law. ▸ Test Cross The cross between heterozygous F1 and homozygous recessive is called test cross. In test cross, the monohybrid ratio is 1 : 1 and dihybrid ratio is 1:1:1:1. ▸ Back Cross The cross between heterozygous F1 hybrid and homozygous dominant allele is called back cross.
▸ Phenotype It is the physical appearance of an individual. ▸ Genotype It is the entire genetic complement of an individual organism. ▸ Alleles The two individual genes in a particular gene pair that occupies same locus (position) on homologous pair of chromosome. ▸ Dominant and Recessive Traits (inherited character) The traits may be dominant or recessive depending upon the fact that on crossing the individuals (which are homozygous for a particular trait of same character the trait which appears in the F1 generation is called dominant and the other one is recessive. ▸ Hybrid An offspring, which is obtained from a cross between two genetically different parents. ▸ Linkage The phenomenon of genic inheritance in which genes of a particular chromosome show their tendency to inherit together, i.e., tendency to retain their parental combination even in the offsprings is known as linkage. ▸ Mutation It is a sudden change of a gene (gene mutation) or chromosome (chromosomal mutation) from one form to another, which are passed to the daughter cells. ▸ Heteroploidy It is the variation in chromosome number. ▸ Pleiotropy It occurs when one gene influences multiple phenotypic traits.
The important human genetic disorders can be categorised as follows Human Genetic Disorder due to Autosomal Abnormalities
Disorder
Chromosome Complement
Effect
Down's syndrome
Trisomy 21 (extra chromosome number)
Short stature, epicanthus, small round head, protruding lower lip, flattened nasal bridge, mental retardation, short life, daffiness.
Edward's syndrome
Trisomy 18 (extra chromosome number)
Long but narrow skull, small face, short digits, webbed neck, corneal opacity, mental retardation.
Cri-du-chat syndrome
Deletion is short arm of chromosome 5
Microcephaly, encrusted distance between eyes, moon face, severe mental deficiency, cat like cry of neonate.
Patau's syndrome
Trisomy 13 (extra chromosome number)
Left plate and lip, polydactyl, mental retardation, anomalies in dermal pattern, heart viscera and genitalia.
Human Genetic Disorder due to Abnormalities in Sex-Chromosome Number
Turner's syndrome
44+XO (45)
Phenotypically female, sterile due to undifferentiated gonads, webbed neck, low posterior hair line increased carrying angle of elbow, short stature.
Noonan's syndrome
44+ YO (45)
Phenotypically male, short stature, webbed neck, drooping upper eyelid, little development of gonads.
Super males
44+XYY (45)
Male, tall, excess testosterone secretions, subnormal intelligence.
Super females
44+XXX(47) 44+XXXX(48)
Female, mental retardation, low fertility but genitalia normal.
Klinefelter's syndrome
44+XXY(47) 44+XXYY(48)
Male tall with long legs, some with gynecomastia, small testes, azospermia, infertile, increased excretion of gonadotropin.
Human Genetic Disorder Human Genetic Disorder due to Gene Mutations in Autosomes (Chromosome that is not a sex chromosome)
Phenylketonuria
Recessive
Autosomal (chromosome 12)
Failure of brain to develop infancy mental retardation.
Defective form of enzyme phenyl alanine hydroxylase.
Sickle-cell anaemia
Autosomal (chromosome 11)
Aggregation of erythrocytes, more rapid destruction of erythrocytes leading to anaemia.
Abnormal haemoglobin in RBCs
Haemophilia A/B
Sex-linked (X-chromosome)
Failure of blood to clot.
Defective form of blood clotting factor VIII/IX.
Colour blindness
Failure to discriminate between red and green colour.
Defect in either red or/and green cones.
Huntington's disease
Dominant
Autosomal (chromosome 4)
Gradual degeneration of brain tissue in middle ages.
Production of an inhibitor of brain cell metabolism.
Cystic fibrosis
Autosomal (chromosome 7)
Mucus clogging in lungs, liver and pancreas anomalies.
Failure of chloride ion transport mechanism.
It deals with technique of using live micro-organisms, their parts or processes for the manufacture of useful or commercial substances. It has two core techniques i.e., genetic engineering and technique to facilitate the growth and multiplication of only desired microbes. In genetic engineering (also called recombinant DNA technology) restriction endonucleases are very useful. They cleave the DNA at specific locations called restriction sites. ▸ Vectors are organisms or their parts used to transfer the desired DNA from one organism to another. The common vectors are bacteriophage, cosmids, phagemids, plasmids etc. ▸ Polymerase Chain Reaction (PCR) developed by KaryMullis (1983) can clone or amplify the small amount of DNA. It involves denaturation, primer annealing and polymerisation in the definite sequence.
A number of transgenic plants, medicines, acids are produced through genetic engineering.
It was developed to reduce the heavy reliance on pesticides. The bacterium Bacillus thuringiensis (Bt) naturally produces a chemical harmful only to a small fraction of insects.
It is a transgenic brinjal (also known as an egg plant or aubergine) created by inserting a crystal protein gene (Cry IAc) from the soil bacterium Bacillus thuringiensis into the genome of various brinjal varieties.
▸ It is a variety of Oryza sativa (rice) produced through genetic engineering to biosynthesise beta-carotene, a precursor of pro-vitamin-A in the edible parts of rice. Golden rice was developed as a fortified food to be used in areas, where there is a shortage of diet having vitamin-A. ▸ Golden Rice 2 produces up to 23 times more beta-carotene than the original variety of golden rice. Golden rice was created by lngo Potrykus of the Institute of Plant Sciences at the Swiss Federal Institute of Technology, working with Peter Beyer of the University of Freiburg. ▸ Carotene impart orange colour to carrots and is the reason why genetically modified rice is golden. For the golden rice to make beta-carotene, three new genes are inserted: two from daffodils and the third from a bacterium.
By the use of antisense RNA technology the enzyme polygalacto-uronase, which causes damage to pectin is deactivated and the tomato is kept fresh for longer duration.
It is either of rape seed (Brassica napus L) or field mustard (Brassica campestris L or Brassica rapavar). Its nodes are used to produce edible oil suitable for consumption by humans and livestock. The oil is also suitable as biodiesel.
▸ Cheese is prepared by the coagulation of casein and other minor milk proteins (curdling of milk) by an enzyme rennin extracted from calf gastric mucosa. ▸ Streptococcus and Lactobacillus species are involved in the manufacture of most cheese. Bacillus thuringiensis (Bt) It is Gram positive, soil-dwelling bacterium, commonly used as a biological pesticide. The Cry toxin found in the bacterium is extracted and used as a pesticide. It also occurs naturally in the gut of caterpillars of various types of moths and butterflies, aswell as on the dark surfaces of plants. ▸ In cheese manufacture, micro-organisms are important in both souring and ripening processes. ▸ Semisoft blue Roquefort cheese of France is produced using the mold Penicillium roqueforti. ▸ Yoghurt is a preserved milk product having a distinct taste and a thick texture than milk. ▸ Yoghurt is made by fermenting whole milk with a mixture of Lactobacillus bulgaricus, Streptococcus lactis and S. thermophilus at 40° to 46°C.
▸ Vitamin C was the first vitamin to be produced by a fermentation process using Acetobacter, a wild bacterium. ▸ Bacteria used for industrial production of vitamin-B12 are propionibacterium shermanii, P. freundenreichii and Pseudomonas denitrificans. ▸ Vitamin-B2 (Riboflavin) is synthesised by many micro-organisms including bacteria, yeasts and fungi. The fungus, Ashbya gossypii is used for the microbial production of vitamin-B2.
▸ Monoclonal antibodies are made outside the body by the hybrid cell cultures known as hybridomas. ▸ Monoclonal antibodies (mAb) are antibodies that are identical because they were produced by one type of immune cell and are all clones of a single parent cell. ▸ A biochip is a discrete collection of gene fragments on a stamp-sized chip that can be used to screen for the presence of particular gene variants. ▸ Biochips allow rapid screening of gene profiles, a tool that promises to have a revolutionary impact on medicine and society. ▸ Biochips can help in identifying precise forms of cancer. ▸ Gene therapy is the treatment of disease by replacing, altering or supplementing a gene whose absence or abnormality is responsible for the disease. Gene therapy is unique as it employs the genetic material, i.e. DNA, itself as the means of treatment. DNA finger printing is the technique, in which the banding pattern of DNA fragments is compared and can be used in many species, including human, to indicate relativity. (used for rape victim, paternity, other criminals). ▸ Human insulin or humulin is the first genetically engineered pharmaceutical product, developed by Eli Lilly and company in 1982. ▸ Genentech, a California-based company, have produced human growth hormone (hGH) from genetically engineered bacteria. ▸ Somatostatin is the first polypeptide, which was expressed in E coli as a part of the fusion peptide. ▸ BST or Bovine Somatotropin is produced in a large quantity from milk production in cows. ▸ In 1997, a transgenic cow 'Rosie' produced human alpha-lactalbumin protein enriched milk (2.4 grams per litre). ▸ It is possible to cure phenylketonuria disease by using recombinant DNA techniques in early period of pregnancy. ▸ Urokinase is involved in dissolution of blood clots. It has been synthesised in huge quantity by using genetically engineered bacteria with urokinase genes. Organic Acids Synthesised by Various Microbes
Lactic acid
Lactobacillus delbreukii, L bulgaricus, Streptococcus lactis and Rhizopus species
Acetic acid (vinegar)
Acetobactor aceti
Citric acid
Aspergillus niger, Penicillium sp and Mucor sp.
Gluconic acid
Aceobacter aceti, Aspergillus niger, Penicillium and Chrysogenum
Propionic acid
Propionibacterium
Butyric acid
Clostridium acetobutylicum
Oxalic acid
Aspergillus sp.
Gallic acid
Aspergillus niger
Some amino acids
Escherichia coli
Types of Antibiotic with their Source and Action
Penicillin
Penicillium chrysogenum, P notatum + Phenyl Acetic Acid
Tonsilitis, Sore Throat, Gonorrhea, Rheumatic Fever, some Pneumonia types
Griseofulvin
Penicillium griseofulvum
Antifungal, especially for Ringworm
Nystatin
Streptomyces noursei
Antifungal for Candidiasis and overgrowth of Intestinal Fungi during excessive antibiotic treatment.
Hamycin
Streptomyces pimprina
Antifungal Antibiotic
Fumagillin
Broad spectrum antibacterial especially against Salmonella and Shigella.
Bacitracin
Bacillus licheniformis
Syphilis, Lymphonema or Reticulosis.
Streptomycin
Streptomyces griseus
Meningitis, Pneumonia, Tuberculosis and Local Infection. Toxic in some, through eighth cranial nerve.
Chloramphenicol Chloromycetin
Streptomyces venezuelae, S. lavendulae
Typhoid, Typhus, Whooping cough, Atypical Pneumonia, Bacterial Urinary Infections.
Tetracyclines/ Aureomycin
Streptomyces aureofaciens
Viral pneumonia, Osteomyelitis, Whooping Cough. Eye infections.
Oxytetracycline/ Terramycin
Chlorotetracycline → Hydrogenation Streptomyces rimosus
Intestinal and Urinary Infections (Spirochaetes, Rickettsia, Viruses)
Erythromycin
Streptomyces erythreus ( = S. erythraeus)
Typhoid, Common Pneumonia, Diphtheria, Whooping Cough etc.
Gentamycin
Micromonospora purpurea
Effective against Gram (+) bacteria
Polymixin
Bacillus polymyxa
Antifungal
▸ It is the branch of biology which deals with plants, which are considered as multicellular ulcerates. The cells of these organisms contain a cell wall made up of cellulose and other polysaccharides. Plants have the ability to synthesise their own food (autotrophic) in the presence of sunlight, via the process of photosynthesis. ▸ Plants have two main groups i.e., cryptogams (lower plants without well defined flowers and seeds) and phanerogams (higher plants with well defined flowers and seeds). ▸ Cryptogams further contains thallophytes and pteridophytes with bryophytes in between. Here, thallophytes means those plants which have thallus like body i.e., without roots, leaves and stem e.g., algae, fungi, bacteria etc. ▸ All the plants of cryptogams are considered as primitive as these do not have well defined features of plants like presence of phloem (a tissue for food transport) and presence of xylem (a tissue for water transport etc). ▸ Phanerogams are well defined advanced plants with proper roots, leaves and stem and well differentiated tissue system. These can be categorised as Gymnosperms (Naked Seed) and Angiosperms (Covered seed) plants. ▸ Algae like Nostoc, Anabaena etc are used as manure. ▸ Sphagnum a genus of mosses is used as fuel and antiseptic. ▸ Some plants catch insects to fulfill their nitrogen requirement. Such plants are called insectivorous plants.
Plant morphology represents a study of the development, form and structure of plants and by implication, an attempt to interpret these on the basis of similarity of plan and origin.
▸ Plant classification is the placing of known plants into groups or categories to show their relationship. ▸ Thus, plants are classified into group having same characteristics. ▸ Thallophyta A phylum of plants of very diverse habit and structure, e.g., Algae, fungi and lichens. ▸ Bryophytes Have stems and leaves but lack true vascular tissue and reproduce by spores e.g., Mosses, hornworts, liverworts etc. ▸ Pteridophytes Vascular plants with leaves, stems and roots, but lack both seeds and flowers, e.g., Ferns, Lycopodium, horsetails etc. ▸ Gymnosperms Group of seed producing plants. A plant that has seeds unprotected by an ovary or fruit, e.g., Conifer, cycads, pine tree etc. ▸ Angiosperms (Vascular plants) A major group of flowering plants. Their characteristics are the possession of protected seeds or fruits, e.g., Rose, tulip, tomatoes etc. Virus The term virus was given by Pasteur. Virus was discovered by Iwanowski in the extract of diseased tobacco plant. Virus is a nucleoprotein entity which do not have machinery of its own but can utilise the synthetic machinery of living cell of other organisms for its multiplication. Virus is considered to be a cellular, i.e. without a cell. Bacteria Basically, bacteria are unicellular prokaryotes. Their cell wall is generally, made up of peptidoglycans and polysaccharides. Genetic material is not organised into nucleus, i.e. a primitive nucleus is present (without a nuclear membrane). All membrane bound cell organelles are absent. Flagella, if present is single-stranded, made up of protein flagellin. Gamete formation is absent.
Different parts of a plant perform different function. Accordingly they are divided into root, stem, leaves, flower, fruits and seeds.
It is that part of plant body, which develops from radicle and grows down into the earth. It gives secondary and tertiary roots. Plants have two types of root systems 1. Tap root develop from radicle, normally found in dicot plants. 2. Adventitious root with a main tap root that is larger and grows faster than the branch roots.
Conical This type of root is thickened towards base but thin near the side of the plant, e.g., Carrot. Napiform This type of root is very broad at the top and tapering like a tail at the bottom, e.g., turnip, beet root etc. Fusiform This type of root is inflated in the middle portion, while thin towards bottom and top, e.g., Radish. Pneumatophores This type of root is found in salty soil near the sea and for the respiratory activities, it undergoes toward negative geotropism, e.g., Rhizophora, plant sundari etc. Mycorrhizal These roots are known from 90% of plant species and are mutualistic association of a fungus with plant root tissue. Most plants require specificmycorrhizal fungi without, which they are unable to absorb sufficient quantities of P, Zn and Mn. The fungus takes the place of root hairs and may penetrate the cortex completely (endomycorrhizae) or remain on the surface of the root (ectomycorrhizae). Functions of Root ▸ Keeps the plants static. ▸ Transports water and mineral salts to the stem and ultimately to the leaves. ▸ Absorbs water and mineral salts from the soil.
It is the ascending organ of the plant, which is formed by the elongation of plumule. Thus, stem is that part of the plant, which originates from plumule and goes towards sunlight opposite to the gravity.
In the adverse conditions underground stems store their food and become thickened and tuberous. Various types of modifications can be described as Stem tuber Potato Bulb Onion, garlic, tulips, lilies etc. Corm Gladiolus, Crocus sativus or saffron etc. Rhizome Ginger, turmeric, arrow root etc. SubaerialModifications There are various types of modifications exists in such types of stem Runner Grass root, Mereilia etc. Stolon Mint, jasmine, strawberry etc. Offset Water hyacinth, Pistia etc. Sucker Pudira, chrysanthemum etc. AerialModifications Various aerial modifications are: Stem tendril Grape Stem thorn Lemon, roses, jujube plum or Chinese date Phylloclade Cactus Bulbils Ruscus.
It is a green part, its main function is to make food through photosynthesis and respiration. Leaves are mainly of two types 1. Simple Leaf A leaf having one blade but blade is not divided, e.g.,mango. 2. Compound Leaf A leaf with more than one blade. All blades are attached to a single leaf stem, e.g., Rose, orange etc.
Leaf Base It is the lowermost part of the leaf, borne onto the node of the stem or its branches. Petiole The stalk of leaf that connects the lamina with the stem or its branch is called petiole. Lamina It is the terminal, flattened, green and conspicuous part of a leaf and is specialised to manufacture food (photosynthesis).
The arrangement of flowers on a floral axis is called inflorescence. The portion of stem that bear cluster of flowers is called peduncle and the stalk of individual flower is called pedicel. The inflorescence has been classified into five distinct types according to modes of branching and modification of peduncle. Solitary Racemose Cymose Mixed Specialized Out of four, two types aremost important. Racemose Inflorescence In racemose inflorescence, the main axis is capable of continuous growth. The flowers show acropetal succession on the main axis. Cymose Inflorescence In cymose inflorescence, the main axis ends in a flower, since the peduncle stops growing. The flowers show basipetal succession. Common Racemose Inflorescence and their Presence
Spike
Adhatoda
Spikelet
Catkin
Morus
Spadix
Banana and maize
Corymb
Iberis amara (candy tuft)
Capitulum (head)
Sunflower
Special
Inflorescence and their presence
Cyathium
Euphorbiaceae family
Verticillaster
Ocimum and Leucus
Hypanthodium
Ficus
Differences between Stem and Root
Cuticle or cutinised outer walls of epidermal cells present.
Cuticle or cutinised outer walls absent.
Epidermis is protective in function.
Epidermis (young) is absorptive in function. It is called epiblema or rhizodermis.
Stomata is present in epidermis.
Stomata is absent in epiblema.
Stem hairs are additional cells, i.e., they do not arise as outgrowths of epidermal cells.
Root hairs are tubular outgrowths of the epiblema (epidermal) cells.
Chloroplasts may be present in some outer cells of the cortex.
Chloroplast almost absent.
Cortex narrow.
Cortex broad.
Endodermis is inconspicuous.
Endodermis is conspicuous.
Pericycle not involved in secondary growth.
Pericycle actively involved in root branches formation and in secondary growth.
Xylem characteristically endarch.
Xylem characteristically exarch.
Xylem and phloem fibres present.
Xylem and phloem fibres usually absent.
Secondary growth, if occurs, takes place by primary cambium, which is both interfascicular and intrafascicular.
Secondary growth, if present, takes place by secondary cambium, the conjunctive parenchyma and pericycle start meristematic activity and participate.
It is a modified shoot that consists of accessary whorls (calyx and corolla) and essential whorls (androecium and gynoecium). The plant, which bears both male and female flower is called monoecious, while separate plants with one type of flower are called dioecious.
The outermost whorl consisting of units called sepals; these are typically green and enclose the rest of the flower in the bud stage, however, they can be absent or prominent and petal-like in some species.
The next whorl toward the apex, composed of units called petals, which are typically thin, soft and coloured to attract animals that help the process of pollination.
The next whorl, consisting of units called stamens. It consist of two parts–a stalk called a filament, topped by an anther, where pollen is produced by meiosis and eventually dispersed.
▸ The innermost whorl of a flower, consisting of one or more units called carpels. The carpel or multiple fused carpels form a hollow structure called an ovary, which produces ovules internally. ▸ Ovules are megasporangia and they in turn produce megaspores by meiosis, which develop into female gametophytes. These give rise to egg cells. ▸ The gynoecium of a flower is also described using an alternative terminology, wherein the structure one sees in the innermost whorl (consisting of an ovary, style and stigma) is called a pistil. ▸ A pistil may consist of a single carpel or a number of carpels fused together. The sticky tip of the pistil, the stigma, is the receptor of pollen. The supportive stalk, the style, becomes the pathway for pollen tubes to grow from pollen grains adhering to the stigma.
Transfer of pollens from stamens to stigma is called pollination. It is of two types Self-pollination Transfer of pollen from stamen to the stigma of same flower or different flower of the same plant. Cross–pollination In this, pollen reach from anther of one flower to the stigma of different flower of same species. This is done with the help of air, water, insects or animals (agents of pollination). In most flowers, maximum pollination occurs by the method of anemophily (by mind). In this mode, pollen-loss is maximum.
It is ripened ovary of flower. The fruit may be true (formed from ovary alone) or false (developed from other part of flower except ovary). These are of three main types, i.e., simple, aggregate and composite. Simple Fruit A simple fruit always develops from a single ovary containing one or more carpels and may or may not include additional modified accessory floral (perianth) structures. In addition, a simple fruit is either fleshy or dry. Fleshy fruits are edible and are seen in the fresh fruit and vegetable section of your local super market. Aggregate Fruits These are groups of simple fruits, developed from multicarpellary or polycarpellary, apocarpous ovary of a flower. These are etaerio of follicle, etaerio of achenes, etaerio of berries and etaerio of drupes. Composite Fruits A composite ormultiple fruit develops from the complete inflorescence. These are of two types Sorosis A multiple fruit derived from just the pistils of many unisexual flowers of an inflorescence, e.g., Mulberry, jackfruit, pineapple etc. Syconus A multiple fruit derived from numerous ovaries borne on the inside of the fleshy receptacle of an inflorescence. Also in accessory fruit, the fleshy portion of the fruit is formed by the hollow peduncle of the (inside-out) inflorescence, e.g., peepal, gular.
Seed is a fertilised mature ovule that possesses an embryonic plant. There are two types of seeds Non-endospermic seeds non-albuminous seed Endosperm is absent in this seed and stores their food material in cotyledons, e.g., Gram, pea. Endospermic or albuminous seed These possess endosperm and store their food in it, e.g., Castor, maize, rice.
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