CHEM 301 Biochemistry Midterm Examination
latest exam 2026!!
Athabasca University
Latest Updated 2025/2026
Total Questions: 85
Time Limit: 3 Hours
Instructions: Choose the single best answer for each question. Correct answers are indicated in [bold
brackets] at the end of each question option set. A rationale follows each section.
SECTION A: CELLS AND THE FOUNDATIONS OF BIOCHEMISTRY (Questions 1-20)
1. Which six elements collectively make up approximately 99% of the mass of most living cells?
a) Carbon, hydrogen, nitrogen, oxygen, sodium, and potassium
b) Carbon, hydrogen, nitrogen, oxygen, calcium, and phosphorus
c) Carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus
d) Carbon, hydrogen, nitrogen, oxygen, iron, and magnesium
[Answer: b]
2. What four elements are most commonly found in biomolecules due to their similar size and
bonding geometry, allowing them to "stack" well together?
a) H, C, N, O
b) C, H, O, P
c) C, H, O, S
d) H, C, N, Ca
[Answer: a]
3. A researcher places a sample of microorganisms in a sterile, sealed flask containing only distilled
water. According to the principles discussed in the course, which observation would be the LEAST
ambiguous indicator of metabolic activity?
a) A decrease in the turbidity of the solution.
b) An increase in the temperature of the solution.
c) A change in the color of the solution from clear to yellow.
d) The formation of a precipitate at the bottom of the flask.
[Answer: b]
4. Which of the following correctly pairs an organelle with its primary function?
a) Lysosome / ATP synthesis
b) Ribosome / Protein digestion
c) Golgi apparatus / Protein modification and secretion
d) Nucleolus / DNA replication
[Answer: c]
,5. A primary structural feature that distinguishes eukaryotic cells from prokaryotic cells is the
presence of:
a) A cell membrane
b) Ribosomes
c) A nucleus
d) A cytoskeleton
[Answer: c]
6. How is DNA typically organized in prokaryotic cells?
a) Linear and packaged with histones
b) Circular and negatively supercoiled
c) Linear and associated with the endoplasmic reticulum
d) Circular and enclosed within a nuclear membrane
[Answer: b]
7. The cytoskeleton is a feature of eukaryotic cells responsible for:
a) Protein synthesis
b) ATP production
c) Cell shape and motion
d) Digestion of cellular debris
[Answer: c]
8. Which organelle contains its own DNA and is thought to have originated from an endosymbiotic
event?
a) Lysosome
b) Golgi apparatus
c) Mitochondrion
d) Ribosome
[Answer: c]
9. The "law of mass action" in biochemistry states that:
a) The rate of a reaction is independent of reactant concentrations.
b) The mass of products must always equal the mass of reactants.
c) The rate of a chemical reaction is proportional to the active masses of the reacting substances.
d) The total mass of a system remains constant over time.
[Answer: c]
10. An amphiphilic molecule is best described as one that:
a) Readily dissolves in nonpolar solvents.
b) Possesses both polar (hydrophilic) and nonpolar (hydrophobic) regions.
c) Can act as both an acid and a base.
d) Has a high heat of vaporization.
[Answer: b]
11. What is the primary function of the Golgi apparatus?
a) To synthesize ATP through cellular respiration.
b) To digest worn-out organelles and foreign substances.
, c) To modify, sort, and package proteins for secretion or delivery to other organelles.
d) To serve as the site of protein synthesis.
[Answer: c]
12. In the context of cellular organization, what is the cytosol?
a) The aqueous interior of the cell, excluding the organelles.
b) Another term for the cytoskeleton.
c) The semi-permeable barrier surrounding the nucleus.
d) The internal fluid within the mitochondria.
[Answer: a]
13. Which of the following is NOT considered one of the four major classes of biomolecules?
a) Proteins
b) Nucleic acids
c) Lipids
d) Sulfates
[Answer: d]
14. Ribosomes are complex molecular machines responsible for:
a) Lipid synthesis
b) Protein synthesis
c) Carbohydrate breakdown
d) DNA replication
[Answer: b]
15. A prokaryotic cell reproduces by a process known as:
a) Mitosis
b) Meiosis
c) Binary fission
d) Budding
[Answer: c]
16. The term "phylogeny" refers to:
a) The study of cellular organelles.
b) The evolutionary history of an organism or group of organisms.
c) The three-dimensional structure of a protein.
d) The chemical reactions occurring in a cell.
[Answer: b]
17. Which of the following best describes the function of a lysosome?
a) Energy production
b) Lipid biosynthesis
c) Intracellular digestion
d) Protein folding
[Answer: c]
latest exam 2026!!
Athabasca University
Latest Updated 2025/2026
Total Questions: 85
Time Limit: 3 Hours
Instructions: Choose the single best answer for each question. Correct answers are indicated in [bold
brackets] at the end of each question option set. A rationale follows each section.
SECTION A: CELLS AND THE FOUNDATIONS OF BIOCHEMISTRY (Questions 1-20)
1. Which six elements collectively make up approximately 99% of the mass of most living cells?
a) Carbon, hydrogen, nitrogen, oxygen, sodium, and potassium
b) Carbon, hydrogen, nitrogen, oxygen, calcium, and phosphorus
c) Carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus
d) Carbon, hydrogen, nitrogen, oxygen, iron, and magnesium
[Answer: b]
2. What four elements are most commonly found in biomolecules due to their similar size and
bonding geometry, allowing them to "stack" well together?
a) H, C, N, O
b) C, H, O, P
c) C, H, O, S
d) H, C, N, Ca
[Answer: a]
3. A researcher places a sample of microorganisms in a sterile, sealed flask containing only distilled
water. According to the principles discussed in the course, which observation would be the LEAST
ambiguous indicator of metabolic activity?
a) A decrease in the turbidity of the solution.
b) An increase in the temperature of the solution.
c) A change in the color of the solution from clear to yellow.
d) The formation of a precipitate at the bottom of the flask.
[Answer: b]
4. Which of the following correctly pairs an organelle with its primary function?
a) Lysosome / ATP synthesis
b) Ribosome / Protein digestion
c) Golgi apparatus / Protein modification and secretion
d) Nucleolus / DNA replication
[Answer: c]
,5. A primary structural feature that distinguishes eukaryotic cells from prokaryotic cells is the
presence of:
a) A cell membrane
b) Ribosomes
c) A nucleus
d) A cytoskeleton
[Answer: c]
6. How is DNA typically organized in prokaryotic cells?
a) Linear and packaged with histones
b) Circular and negatively supercoiled
c) Linear and associated with the endoplasmic reticulum
d) Circular and enclosed within a nuclear membrane
[Answer: b]
7. The cytoskeleton is a feature of eukaryotic cells responsible for:
a) Protein synthesis
b) ATP production
c) Cell shape and motion
d) Digestion of cellular debris
[Answer: c]
8. Which organelle contains its own DNA and is thought to have originated from an endosymbiotic
event?
a) Lysosome
b) Golgi apparatus
c) Mitochondrion
d) Ribosome
[Answer: c]
9. The "law of mass action" in biochemistry states that:
a) The rate of a reaction is independent of reactant concentrations.
b) The mass of products must always equal the mass of reactants.
c) The rate of a chemical reaction is proportional to the active masses of the reacting substances.
d) The total mass of a system remains constant over time.
[Answer: c]
10. An amphiphilic molecule is best described as one that:
a) Readily dissolves in nonpolar solvents.
b) Possesses both polar (hydrophilic) and nonpolar (hydrophobic) regions.
c) Can act as both an acid and a base.
d) Has a high heat of vaporization.
[Answer: b]
11. What is the primary function of the Golgi apparatus?
a) To synthesize ATP through cellular respiration.
b) To digest worn-out organelles and foreign substances.
, c) To modify, sort, and package proteins for secretion or delivery to other organelles.
d) To serve as the site of protein synthesis.
[Answer: c]
12. In the context of cellular organization, what is the cytosol?
a) The aqueous interior of the cell, excluding the organelles.
b) Another term for the cytoskeleton.
c) The semi-permeable barrier surrounding the nucleus.
d) The internal fluid within the mitochondria.
[Answer: a]
13. Which of the following is NOT considered one of the four major classes of biomolecules?
a) Proteins
b) Nucleic acids
c) Lipids
d) Sulfates
[Answer: d]
14. Ribosomes are complex molecular machines responsible for:
a) Lipid synthesis
b) Protein synthesis
c) Carbohydrate breakdown
d) DNA replication
[Answer: b]
15. A prokaryotic cell reproduces by a process known as:
a) Mitosis
b) Meiosis
c) Binary fission
d) Budding
[Answer: c]
16. The term "phylogeny" refers to:
a) The study of cellular organelles.
b) The evolutionary history of an organism or group of organisms.
c) The three-dimensional structure of a protein.
d) The chemical reactions occurring in a cell.
[Answer: b]
17. Which of the following best describes the function of a lysosome?
a) Energy production
b) Lipid biosynthesis
c) Intracellular digestion
d) Protein folding
[Answer: c]
