7th Grade Biology Study Guide

Characteristics of Living Things
1. Made of one or more cells
2. Genetic material
3. Sense and respond to internal/external stimuli/ are able to maintain homeostasis
4. Reproduce
5. Grow and develop
6. Use energy
7. DNA

ATP (Adenosine Tri-Phosphate)
The molecule produced in the mitochondria from carbohydrates that provides energy for the cell.

Phospholipids
The type of lipid that not only stores carbs, but also forms a bilayer around the cell called the cell membrane. The head is attracted to water(hydrophilic) and the tail is repelled by water(hydrophobic).

Carbohydrates
Molecules that are converted into ATP. Contain carbon, hydrogen, and oxygen. Includes sugars, starches, fibers, cellulose, chitin, glucose, glycogen, etc.

Eukaryotic vs Prokaryotic Cell
Eukaryotic Cells:
1. Have nucleus
2. Have membrane bound organelles
3. Unicellular or multicellular

Prokaryotic Cells:
1. Have nucleoid region
2. Unicellular

Both:
1. Ribosomes
2. Cytoplasm
3. Cells XD
4. Living :P (characteristics of life)
5. Flagella

Plant cell

3 things plant cells have that animal cells do not:
1. Central Vacuole- expanding and contracting compartment that stores water, nutrients, and waste for the cell.
2. Cell Wall- Stiff barrier around the cell membrane that provides support, protection, and structure for the cell.
3. Chloroplast- organelles that contain the green pigment chlorophyll. Site of photosynthesis

Nucleus
Control center of the cell. Houses the genetic material and nucleolus. Only present in eukaryotic cells.

Nucleolus
Part of the nucleus that begins the assembly of ribosomes.

Smooth ER (endoplasmic reticulum)
Organelle that breaks down toxins and makes lipids. No ribosomes present.

Nucleoid (region)
General area in prokaryotic cells where the single loop of genetic material resides.

Natural Selection
Charles Darwin's evolutionary theory that the organisms in a species with 'favorable' traits, like camouflage, survive and reproduce more than the others.

Common Ancestor
All organisms are believed to have evolved from a common ancestor of all life forms.

Genetic Variation- 3 Ways:
1. Mutations- random changes in genetic material
2. Migrations- when organisms with different adaptations move to a place with different adaptations and reproduce with that group
3. Sexual Reproduction- when genes from two parents combine to form the offspring's genes

Adaptation
Any trait that helps an organism survive better in an environment (webbed feet, long tail, etc)

Artificial selection
Humans selectively breeding for traits they think are 'favorable'

Levels of Classification
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

How many domains of life are there?
3

What are the 3 domains of life called?
1.Bacteria (prokaryotic)
2.Archaea (prokaryotic)
3.Eukarya (eukaryotic)

Scientific Naming
Linnaean Taxonomy- like Russian dolls, based on DNA. Genus species- all underlined or italicized.

Binary Fission
Asexual Bacteria replication in which the mother cell splits into two cells.

Archaea vs Bacteria
Archaea:
-not all have cell wall
-chemically different
-closer to eukarya than bacteria

Bacteria:
-cell wall

Both:
-prokaryotic
-living
-unicellular

Virus Replication
Lytic and Lysogenic Cycle

Lytic cycle
1. Virus injects genetic material into cell
2. Cell immediately becomes virus making factory

Lysogenic Cycle
1. Virus injects genetic material into cell
2. Cell only begins making viruses when triggered, then switches to lytic cycle

Virus Protein Coat
shell that protects the genetic material inside

Symbiosis
A relationship between two different species in which at least one of them benefits and they live together

Lichen
A symbiotic relationship between a fungus, and algae/cyanobacteria.

General Fungi Characteristics
1. Eukaryotic
2. Heterotrophic (decomposers)
3. Closer to animalia than plantae
4. Store energy as glycogen
5. Chitin in cell walls

Mycelium
Web of hyphae found underground that makes up most of the fungus.

Hyphae
Thread-like filaments that form the mycelium

Phytoplankton
Type of plant-like protist (unicellular algae) that can photosynthesize and make up most of the world's oxygen- diatoms, dinoflagellates, etc.

Protozoan
A protist that can move (animal-like) using at least one of the following:
-flagella- whip like tail used to wiggle around
-cilia- tiny hairlike structures that move
-pseudopodia- extension and contraction of cytoplasm

Pseudopodia
Extension and contraction of cytoplasm

General Protist characteristics
1. Eukaryotic
2. Mostly unicellular, some multicellular
3. NO SPECIALIZED TISSUE
4. Very diverse

Monocot vs. Dicot
Monocot:
-petals in threes
-one cotyledon
-parallel veins
-vascular tissue scattered randomly in stem

Dicot:
-petals in fours or fives
-two cotyledons
-branching veins
-vascular tissue in a ring in stem

Both:
-living
-eukaryotic
-plants
-vascular
-seeds
-angiosperms (flowers)

General Alternation of Generations
Life Cycle of Plants, switches between gametophyte(gametes) and sporophyte(spores)

Gymnosperm Alternation of Generations
Life cycle of gymnosperms, same as others, except 2 different spores are made into two different cones(gametophyte), which make two different gametes, then back to sporophyte

Gas Exchange
Happens in leaves through stomata, which guard cells open and close. Water, oxygen, carbon dioxide, etc.

Vascular Tissue
Xylem and Phloem

Xylem
Vascular tissue that carries water and nutrients up from the roots to the rest of the plant

Phloem (flowm)
Vascular tissue that transports sugars throughout the plant

Flower Structures

Petals
Leaf like structures that help attract pollinators

Sepals
Leaves that protect the developing flower bud

Pistil
Female part of flower:
-Stigma- top of pistil covered in a sticky coating to absorb drifting pollen
-Style- long stalk that holds up stigma
-Ovary- base of pistil that develops the eggs in the ovule

Stamen
Male part of flower:
-Anther- sac that produces pollen
-Filament- stalk that holds up anther for pollinators

Pollination
the process of pollen being transferred to the stigma

Chloroplast
Organelle in plants that contains chlorophyll and is the site of photosynthesis

Cuticle
Waxy layer on plants that prevents it from drying out and from pathogens

Gametophyte
Dominant stage in nonvascular plants. Produces gametes that form the sporophyte

Gymnosperm reproduction
-2 types of spores
-2 types of cones
-2 types of gametes
-1 sporophyte

Vascular Plants
Plants that have vascular tissue to transport materials through plant. Dominant sporophyte.

Gymnosperm and Angiosperm seed plants
Vascular seeded plants

Seeds
Way of dispersing sporophyte before germination, protects the sporophyte with seed coat, provides nourishment with cotyledon.

Fruit
Way that angiosperms hold seeds until they are ready to be dispersed, develops after flower has been fertilized

Photosynthesis
Plant process of taking water and carbon dioxide and converting it into glucose and oxygen using sunlight energy

Stomata
Pores in leaves that are the site of gas exchange

Guard cells
Cells that open and close the stomata

Leaf function
To collect sunlight for the chloroplast.

Germination
The process of the sporophyte growing from the seed

General Animal Characteristics
1. Heterotrophic
2. Eukaryotic
3. Differentiation of cells
4. Multicellular
5. Sexual Reproduction
6. Movement

Do animal cells have cell walls?
NOOOOOOOOOOOOOOOOOOOOOO

Coelom
Central body cavity in which all specialized organs are located

Swim Bladder
bag-like organ filled with gasses in Bony fish that helps regulate their buoyancy

Amphibian skin
Very thin, can absorb water and exchange gases

Arthropod characteristics
-Jointed appendages
-Hard exoskeleton made of chitin like fungal cell walls
-Segmented body:head, thorax, abdomen,

Notochord
stiff, flexible rod that supports chordate bodies.

Metamorphosis
Process of change in form and behavior during life of arthropods, complete or incomplete

Polyp
Cnidarian form in which the tentacles face up (sea anemone)

Medusa
Cnidarian form in which the tentacles face down from a bell-like body

Closed circulation
Circulatory system in which the bodily fluids are always contained in vessels and tubes (cephalopods)

Cephalopods
Invertebrates of phylum Mollusca:
-coelomates
-bilateral symmetry
-complex nervous system-large brain to control ganglia
-tentacles instead of foot
-feed using beak
-closed circulation

Porifera
Invertebrate phylum including sponges:
-acoelomates
-no nervous tissue
-collar cells-filter feeder
-asymmetric, sometimes radial
-simple skeleton of spongin/calcium carbonate
-sexual external fertilization, some asexual by budding
-movement at larvae stage

Cnidaria
Invertebrate phylum:
-acoelomates
-polyp or medusa body form
-radial symmetry
-nerve net
-most carnivores
-use nematocysts to catch prey

Nematocysts
Stinging cells that release barbs with poison into the prey

Adult echinoderm symmetry
Radial! (think starfish)

Roundworms
Invertebrate phylum nematoda:
-pseudocoelomates
-bilateral symmetry
-simple nervous system
-sexual internal fertilization or some asexual

Gastropods
Invertebrates members of phylum Mollusca:
-bilateral symmetry
-coelomates
-ganglia that control body
-foot
-radula (tongue)
-sexual sometimes asexual reproduction
-one shell (not slugs)

Collar Cells
Cells in Porifera that filter water, digest the edible particles, and release the extra water

Pharyngeal Pouches
Chordate characteristic- that develop into gills or other body parts

Gills
Organs in fish that take the oxygen out of water and release the rest back

Chordata
Animal Phylum that includes:
-tunicates
-lancelets
-vertebrates

Characteristics of Chordates
1. Notochord
2. Post-anal Tail
3. Hollow nerve cord
4. Pharyngeal Pouches

Hollow Nerve Cord/Spinal Cord
sensory cord that runs down the back of chordates, called spinal cord in vertebrates

Parasitism
A symbiotic relationship in which one organism benefits, and the other is harmed

Commensalism
A symbiotic relationship in which one organism benefits, and the other is not affected

Mutualism
A symbiotic relationship in which both organisms benefit

Heterotroph
An organism that can NOT produce its own food

Autotroph
An organism that CAN produce its own food

Food Webs
interconnected, overlapping food chains in an ecosystem

Meaning of Arrows in Food Webs/Chains
Represent energy moving from one organism to the other

Outcomes of Disturbances in Food Webs/Chains
Extinction in one category, overpopulation in another

Decomposer
A heterotroph that secretes digestive enzymes outside of body to consume a dead organism

Food Chain
A simple linear diagram showing energy flow

Competition
When 2+ individuals compete for limited resources, and as a result, organisms evolve different adaptations t reduce competition

Acoelomate
Animal that lacks a coelom, or body cavity . examples are flatworms and cnidarians

Coelomate
An animal that has a body cavity in which the internal organs are located

Pseudocoelomate
An animal with a false, fluid filled body cavity

Nucleic acids
DNA and RNA

Proteins
Made up of amino acids

Lipids
Fats

Enzymes
Proteins that speed up chemical reactions

Mitochondria
Powerhouse of the cell, organelle that is the site of ATP (energy) production

Rough ER
ER that is dotted with ribosomes

Eukaryote
Organism whose cells contain a nucleus

Organelle
Any of a number of organized or specialized structures within a living cell.

What is the difference between pollination and fertilization?
Pollination is the process of the pollen coming into contact with the female structure but fertilization occurs afterwards when the sperm fuses with the egg.

What is the job of anthers in a flower? What type of plant has flowers?
Anther produces pollen. Angiosperms are flowering.

What is an adaption? Give an example.
Traits that allow organisms to better survive in there environment
- they may be behavior, physical, characteristics, and chemical characteristics