BIO 1201 (Gregg) Exam 3 —
Comprehensive Practice
Examination questions with
answers
Questions 1–25: Cell Biology and Cellular Energy
1. Which organelle is primarily responsible for producing ATP during aerobic cellular
respiration?
A. Golgi apparatus B. Mitochondrion C. Lysosome D. Ribosome
Answer: B. Mitochondrion
Rationale: Mitochondria produce most ATP during aerobic respiration through the citric acid
cycle and oxidative phosphorylation.
2. Which organelle is responsible for protein synthesis?
A. Ribosome B. Lysosome C. Smooth endoplasmic reticulum D. Centriole
Answer: A. Ribosome
Rationale: Ribosomes translate messenger RNA (mRNA) into polypeptide chains using amino
acids.
3. What is the primary function of the plasma membrane?
A. Store genetic information B. Produce ribosomes C. Regulate substances entering and
leaving the cell D. Generate all cellular ATP
Answer: C. Regulate substances entering and leaving the cell
Rationale: The selectively permeable plasma membrane controls the movement of
substances and helps maintain cellular homeostasis.
4. Which process moves water across a selectively permeable membrane?
A. Active transport B. Osmosis C. Exocytosis D. Phagocytosis
Answer: B. Osmosis
Rationale: Osmosis is the net movement of water across a selectively permeable membrane
in response to differences in water potential.
,5. Which process requires energy directly from ATP to move substances against their
concentration gradient?
A. Simple diffusion B. Osmosis C. Facilitated diffusion D. Active transport
Answer: D. Active transport
Rationale: Active transport uses energy to move substances against their electrochemical
gradients. The sodium-potassium pump is one example.
6. What is the main function of lysosomes?
A. Digest cellular waste and damaged components B. Produce glucose C. Store DNA D.
Assemble spindle fibers
Answer: A. Digest cellular waste and damaged components
Rationale: Lysosomes contain digestive enzymes that break down macromolecules, worn-
out organelles, and other cellular material.
7. Which structure contains most of a eukaryotic cell's genetic material?
A. Golgi apparatus B. Nucleus C. Cell membrane D. Cytoplasm
Answer: B. Nucleus
Rationale: The nucleus houses most eukaryotic DNA and regulates gene expression.
Mitochondria also contain a small amount of DNA.
8. What happens during diffusion?
A. Molecules move from low to high concentration using ATP B. Molecules move only
through protein pumps C. Molecules move down their concentration gradient D. Water is
converted into ATP
Answer: C. Molecules move down their concentration gradient
Rationale: Diffusion is the net movement of particles from an area of higher concentration to
an area of lower concentration due to random molecular motion.
9. Which organelle modifies, sorts, and packages proteins for transport?
A. Golgi apparatus B. Nucleolus C. Peroxisome D. Centriole
Answer: A. Golgi apparatus
Rationale: The Golgi apparatus processes proteins and lipids and directs them to appropriate
cellular destinations.
10. Which statement best describes enzymes?
, A. They increase activation energy B. They are always consumed during reactions C. They
stop all chemical reactions D. They lower activation energy
Answer: D. They lower activation energy
Rationale: Enzymes act as biological catalysts, increasing reaction rates without being
consumed by the reactions they catalyze.
11. What is the primary purpose of cellular respiration?
A. Store genetic information B. Produce usable energy in the form of ATP C. Manufacture all
cellular proteins D. Eliminate the need for oxygen in every cell
Answer: B. Produce usable energy in the form of ATP
Rationale: Cellular respiration transfers energy from organic molecules, such as glucose, into
ATP that cells can use for cellular work.
12. Where does glycolysis occur?
A. Nucleus B. Mitochondrial matrix C. Cytosol D. Golgi apparatus
Answer: C. Cytosol
Rationale: Glycolysis occurs in the cytosol and breaks one glucose molecule into two
pyruvate molecules, producing a net gain of two ATP and two NADH.
13. What is the final electron acceptor in the mitochondrial electron transport chain during
aerobic respiration?
A. Oxygen B. Glucose C. Carbon dioxide D. ATP
Answer: A. Oxygen
Rationale: Oxygen accepts electrons and combines with protons to form water. Without
oxygen, the normal mitochondrial electron transport chain cannot continue operating.
14. Which molecule is the immediate energy currency of most cells?
A. DNA B. RNA C. Glycogen D. ATP
Answer: D. ATP
Rationale: ATP stores transferable chemical energy in its phosphate groups and supplies
energy for processes such as active transport and muscle contraction.
15. Which organelle is the main site of photosynthesis in plant cells?
A. Mitochondrion B. Chloroplast C. Lysosome D. Ribosome
Answer: B. Chloroplast
Comprehensive Practice
Examination questions with
answers
Questions 1–25: Cell Biology and Cellular Energy
1. Which organelle is primarily responsible for producing ATP during aerobic cellular
respiration?
A. Golgi apparatus B. Mitochondrion C. Lysosome D. Ribosome
Answer: B. Mitochondrion
Rationale: Mitochondria produce most ATP during aerobic respiration through the citric acid
cycle and oxidative phosphorylation.
2. Which organelle is responsible for protein synthesis?
A. Ribosome B. Lysosome C. Smooth endoplasmic reticulum D. Centriole
Answer: A. Ribosome
Rationale: Ribosomes translate messenger RNA (mRNA) into polypeptide chains using amino
acids.
3. What is the primary function of the plasma membrane?
A. Store genetic information B. Produce ribosomes C. Regulate substances entering and
leaving the cell D. Generate all cellular ATP
Answer: C. Regulate substances entering and leaving the cell
Rationale: The selectively permeable plasma membrane controls the movement of
substances and helps maintain cellular homeostasis.
4. Which process moves water across a selectively permeable membrane?
A. Active transport B. Osmosis C. Exocytosis D. Phagocytosis
Answer: B. Osmosis
Rationale: Osmosis is the net movement of water across a selectively permeable membrane
in response to differences in water potential.
,5. Which process requires energy directly from ATP to move substances against their
concentration gradient?
A. Simple diffusion B. Osmosis C. Facilitated diffusion D. Active transport
Answer: D. Active transport
Rationale: Active transport uses energy to move substances against their electrochemical
gradients. The sodium-potassium pump is one example.
6. What is the main function of lysosomes?
A. Digest cellular waste and damaged components B. Produce glucose C. Store DNA D.
Assemble spindle fibers
Answer: A. Digest cellular waste and damaged components
Rationale: Lysosomes contain digestive enzymes that break down macromolecules, worn-
out organelles, and other cellular material.
7. Which structure contains most of a eukaryotic cell's genetic material?
A. Golgi apparatus B. Nucleus C. Cell membrane D. Cytoplasm
Answer: B. Nucleus
Rationale: The nucleus houses most eukaryotic DNA and regulates gene expression.
Mitochondria also contain a small amount of DNA.
8. What happens during diffusion?
A. Molecules move from low to high concentration using ATP B. Molecules move only
through protein pumps C. Molecules move down their concentration gradient D. Water is
converted into ATP
Answer: C. Molecules move down their concentration gradient
Rationale: Diffusion is the net movement of particles from an area of higher concentration to
an area of lower concentration due to random molecular motion.
9. Which organelle modifies, sorts, and packages proteins for transport?
A. Golgi apparatus B. Nucleolus C. Peroxisome D. Centriole
Answer: A. Golgi apparatus
Rationale: The Golgi apparatus processes proteins and lipids and directs them to appropriate
cellular destinations.
10. Which statement best describes enzymes?
, A. They increase activation energy B. They are always consumed during reactions C. They
stop all chemical reactions D. They lower activation energy
Answer: D. They lower activation energy
Rationale: Enzymes act as biological catalysts, increasing reaction rates without being
consumed by the reactions they catalyze.
11. What is the primary purpose of cellular respiration?
A. Store genetic information B. Produce usable energy in the form of ATP C. Manufacture all
cellular proteins D. Eliminate the need for oxygen in every cell
Answer: B. Produce usable energy in the form of ATP
Rationale: Cellular respiration transfers energy from organic molecules, such as glucose, into
ATP that cells can use for cellular work.
12. Where does glycolysis occur?
A. Nucleus B. Mitochondrial matrix C. Cytosol D. Golgi apparatus
Answer: C. Cytosol
Rationale: Glycolysis occurs in the cytosol and breaks one glucose molecule into two
pyruvate molecules, producing a net gain of two ATP and two NADH.
13. What is the final electron acceptor in the mitochondrial electron transport chain during
aerobic respiration?
A. Oxygen B. Glucose C. Carbon dioxide D. ATP
Answer: A. Oxygen
Rationale: Oxygen accepts electrons and combines with protons to form water. Without
oxygen, the normal mitochondrial electron transport chain cannot continue operating.
14. Which molecule is the immediate energy currency of most cells?
A. DNA B. RNA C. Glycogen D. ATP
Answer: D. ATP
Rationale: ATP stores transferable chemical energy in its phosphate groups and supplies
energy for processes such as active transport and muscle contraction.
15. Which organelle is the main site of photosynthesis in plant cells?
A. Mitochondrion B. Chloroplast C. Lysosome D. Ribosome
Answer: B. Chloroplast
