STEM Readiness: Pre-Calculus Readiness - Functions/Algebra: Polynomial Long Division - and Synthetic, Division

Must?Know (20–25 detailed bullets)

• Prokaryotic cells range from 0.1–5.0 ?m in diameter; eukaryotic cells range from 10–100 ?m.
• Prokaryotes include bacteria and archaea; eukaryotes include animals, plants, fungi, and protists.
• DNA in prokaryotes is located in the nucleoid, a region without a membrane; eukaryotes house DNA within a membrane-bound nucleus.
• Prokaryotes lack membrane-bound organelles; eukaryotes contain endoplasmic reticulum, Golgi apparatus, lysosomes, and mitochondria.
• Ribosomes in prokaryotes are 70S (50S + 30S subunits); eukaryotic cytoplasmic ribosomes are 80S (60S + 40S subunits).
• Mitochondria and chloroplasts in eukaryotes contain 70S ribosomes, similar to prokaryotes, supporting the endosymbiotic theory.
• Prokaryotic cell walls typically contain peptidoglycan (e.g., Escherichia coli); archaea lack peptidoglycan and have pseudopeptidoglycan or other polymers.
• Plant cell walls are composed of cellulose; fungal cell walls contain chitin; animal cells lack a cell wall.
• Mycoplasma, a bacterium, lacks a cell wall and is resistant to antibiotics targeting peptidoglycan synthesis (e.g., penicillin).
• Both prokaryotes and eukaryotes have a phospholipid bilayer plasma membrane with embedded proteins.
• Eukaryotes have internal membrane systems (e.g., nuclear envelope, ER, Golgi); prokaryotes do not.
• The nuclear envelope in eukaryotes is a double membrane with nuclear pores that regulate transport.
• Nucleolus within the nucleus is the site of ribosomal RNA (rRNA) synthesis and ribosome subunit assembly.
• Mitochondria are the site of aerobic respiration and ATP production; they have cristae (inner membrane folds) and matrix (inner space).
• Chloroplasts in plant cells perform photosynthesis; they contain thylakoids (site of light reactions) and stroma (site of Calvin cycle).
• Lysosomes in animal cells contain hydrolytic enzymes for intracellular digestion; absent in most plant cells.
• Peroxisomes contain oxidative enzymes (e.g., catalase) that break down fatty acids and detoxify hydrogen peroxide.
• Endoplasmic reticulum (ER): Rough ER has ribosomes and synthesizes proteins; smooth ER synthesizes lipids and detoxifies drugs.
• Golgi apparatus modifies, sorts, and packages proteins for secretion or delivery to organelles.
• Cytoskeleton components (microtubules, microfilaments, intermediate filaments) are present in eukaryotes; prokaryotes have homologs (e.g., FtsZ, MreB) but no true cytoskeleton.
• Red blood cells in mammals lack a nucleus and organelles, maximizing space for hemoglobin.
• Plasmids are small, circular DNA molecules found in prokaryotes and some eukaryotes (e.g., yeast); used in genetic engineering.
• Endosymbiotic theory is supported by mitochondria and chloroplasts having circular DNA, 70S ribosomes, and double membranes.
• Binary fission is the method of asexual reproduction in prokaryotes; eukaryotes divide by mitosis and cytokinesis.
• Flagella in prokaryotes are made of flagellin and rotate; eukaryotic flagella are made of microtubules (9+2 arrangement) and undulate.

Difficulty Level

Intermediate – requires distinguishing structural and functional differences across domains and recognizing exceptions.

Common Traps (3–5 factual traps)

Trap: All cells with cell walls have peptidoglycan – Fact: Only bacteria have peptidoglycan; archaea, plants (cellulose), and fungi (chitin) have different wall compositions.
Trap: Ribosome size is the same across all cells – Fact: Prokaryotes use 70S ribosomes; eukaryotes use 80S in cytoplasm, but mitochondria and chloroplasts retain 70S.
Trap: The nucleus is the only organelle that contains DNA in eukaryotes – Fact: Mitochondria and chloroplasts also contain their own DNA.
Trap: Prokaryotes have no internal membranes – Fact: Some prokaryotes (e.g., cyanobacteria) have thylakoid membranes for photosynthesis.
Trap: Eukaryotic cells are always larger and more complex than prokaryotic cells – Fact: Some eukaryotes (e.g., Ostreococcus) are <1 ?m, smaller than many prokaryotes.

Practice MCQs (5–7 questions)

Question: Which of the following is a feature found in prokaryotic cells but not in eukaryotic cells?
A) Circular DNA
B) 70S ribosomes
C) Nucleoid region
D) Phospholipid bilayer
Answer: C
Explanation: The nucleoid is a distinct, non-membrane-bound region in prokaryotes where DNA is located.
Why the top distractor is wrong: While 70S ribosomes (B) are common in prokaryotes, they are also present in mitochondria and chloroplasts of eukaryotes.

Question: Which structure is present in plant cells but absent in animal cells?
A) Mitochondria
B) Lysosome
C) Chloroplast
D) Plasma membrane
Answer: C
Explanation: Chloroplasts are organelles for photosynthesis and are found only in plant and algal cells.
Why the top distractor is wrong: Lysosomes (B) are often considered animal cell organelles but are also present in some plant cells.

Question: A cell is observed to have a nucleus, mitochondria, and a cell wall made of cellulose. From which organism is this cell most likely derived?
A) Fungus
B) Bacterium
C) Animal
D) Plant
Answer: D
Explanation: Cellulose cell walls and chloroplasts (implied by photosynthetic context) are diagnostic of plant cells.
Why the top distractor is wrong: Fungi (A) have chitin in their cell walls, not cellulose.

Question: Which of the following provides the strongest evidence for the endosymbiotic origin of mitochondria?
A) Presence of a double membrane
B) Ability to synthesize proteins
C) Contain 70S ribosomes and circular DNA
D) Divide by binary fission
Answer: C
Explanation: Mitochondria have 70S ribosomes and circular DNA, both traits shared with bacteria.
Why the top distractor is wrong: A double membrane (A) is suggestive but not exclusive evidence; other organelles may have double membranes.

Question: Which of the following cells lacks a nucleus?
A) Yeast cell
B) Human neuron
C) Escherichia coli
D) Onion root cell
Answer: C
Explanation: E. coli is a prokaryote and lacks a membrane-bound nucleus.
Why the top distractor is wrong: Yeast (A) is a eukaryotic fungus and has a nucleus.

Question: What is the primary component of the fungal cell wall?
A) Peptidoglycan
B) Cellulose
C) Chitin
D) Glycogen
Answer: C
Explanation: Fungi have cell walls composed primarily of chitin, a nitrogen-containing polysaccharide.
Why the top distractor is wrong: Peptidoglycan (A) is found in bacterial cell walls, not fungal.

Question: Which organelle is responsible for lipid synthesis and detoxification of drugs in liver cells?
A) Rough ER
B) Golgi apparatus
C) Smooth ER
D) Lysosome
Answer: C
Explanation: The smooth endoplasmic reticulum synthesizes lipids and metabolizes toxins.
Why the top distractor is wrong: Rough ER (A) is involved in protein synthesis, not lipid synthesis.

Last?Minute Revision (20–25 one?liners)

• Prokaryotic cell size: 0.1–5.0 ?m; eukaryotic: 10–100 ?m.
• Prokaryotes: DNA in nucleoid; eukaryotes: DNA in nucleus.
• Prokaryotic ribosome = 70S; eukaryotic cytoplasmic ribosome = 80S.
• Mitochondria and chloroplasts have 70S ribosomes and circular DNA – evidence of endosymbiosis.
• Bacteria: peptidoglycan cell wall; archaea: no peptidoglycan.
• Plant cell wall: cellulose; fungal cell wall: chitin; animal cell: no wall.
• Mycoplasma lacks a cell wall – resistant to penicillin.
• Both prokaryotes and eukaryotes have phospholipid bilayer membranes.
• Eukaryotes have internal membranes (ER, Golgi, nucleus); prokaryotes generally do not.
• Nuclear pores regulate transport between nucleus and cytoplasm.
• Nucleolus = site of rRNA synthesis and ribosome assembly.
• Mitochondria: double membrane, cristae, matrix, site of ATP production.
• Chloroplasts: thylakoids (light reactions), stroma (Calvin cycle).
• Lysosomes contain hydrolytic enzymes; primarily in animal cells.
• Peroxisomes break down fatty acids and detoxify H?O? with catalase.
• Rough ER: protein synthesis; smooth ER: lipid synthesis, detoxification.
• Golgi apparatus: modifies, sorts, packages proteins.
• Cytoskeleton: microtubules, microfilaments, intermediate filaments – eukaryote-specific.
• Prokaryotes use FtsZ (tubulin homolog) and MreB (actin homolog) for division and shape.
• Red blood cells lack nucleus and organelles.
• Plasmids: small circular DNA; common in bacteria, also in yeast.
• Binary fission = prokaryotic division; mitosis = eukaryotic nuclear division.
• Prokaryotic flagella: flagellin, rotary motion; eukaryotic: microtubules (9+2), bending motion.
• Cyanobacteria have thylakoid membranes despite being prokaryotes.
• Mitochondria divide by binary fission – supports endosymbiotic theory.
• Verify from standard textbook: exact protein composition of nuclear pore complex.