BIOL180 Lesson 2 Quiz – Cell Structure
and Function Exam Practice Questions
And Correct Answers (Verified Answers)
Plus Rationale 2026 Q&A| Instant
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1. Which structure is often called the "control center" of a eukaryotic cell
because it houses the genetic material and regulates cellular activities?
A. Ribosome
B. Nucleus
C. Lysosome
D. Golgi apparatus
Rationale: The nucleus contains DNA and controls gene expression, cell
growth, metabolism, and reproduction. It directs the synthesis of proteins
by regulating transcription.
2. Which organelle is primarily responsible for ATP production through
aerobic cellular respiration?
A. Chloroplast
B. Ribosome
C. Mitochondrion
D. Vacuole
,Rationale: Mitochondria generate ATP through the processes of the citric
acid cycle and oxidative phosphorylation, supplying energy for cellular
activities.
3. Ribosomes are the primary sites of:
A. DNA replication
B. Lipid synthesis
C. Protein synthesis
D. ATP storage
Rationale: Ribosomes translate mRNA into proteins by assembling amino
acids into polypeptide chains during translation.
4. Which organelle modifies, sorts, and packages proteins before they are
transported to their destinations?
A. Rough endoplasmic reticulum
B. Golgi apparatus
C. Smooth endoplasmic reticulum
D. Nucleus
Rationale: The Golgi apparatus receives proteins from the rough ER,
modifies them chemically, packages them into vesicles, and directs them to
specific cellular locations.
5. The smooth endoplasmic reticulum is primarily involved in:
A. DNA transcription
B. Protein translation
C. Lipid synthesis and detoxification
D. ATP production
Rationale: The smooth ER synthesizes lipids, metabolizes carbohydrates,
detoxifies harmful substances, and stores calcium ions.
, 6. Which organelle contains digestive enzymes that break down worn-out
organelles and cellular waste?
A. Peroxisome
B. Lysosome
C. Vacuole
D. Centriole
Rationale: Lysosomes contain hydrolytic enzymes capable of digesting
macromolecules, pathogens, and damaged cellular components.
7. Which cellular structure selectively regulates the movement of
substances into and out of the cell?
A. Cell wall
B. Plasma membrane
C. Cytoplasm
D. Nucleolus
Rationale: The plasma membrane is selectively permeable, allowing
specific molecules to cross while maintaining homeostasis.
8. According to the fluid mosaic model, the plasma membrane primarily
consists of:
A. Cellulose and proteins
B. Chitin and phospholipids
C. Phospholipids with embedded proteins
D. DNA and carbohydrates
Rationale: The plasma membrane is composed of a phospholipid bilayer
containing proteins, cholesterol, and carbohydrates that contribute to
membrane function.
9. Which component of the plasma membrane provides flexibility while
acting as a barrier to water-soluble substances?
, A. Cholesterol
B. Glycoproteins
C. Phospholipid bilayer
D. Cytoskeleton
Rationale: The phospholipid bilayer forms the structural foundation of the
membrane, with hydrophilic heads and hydrophobic tails creating selective
permeability.
10. Which molecule moves directly through the phospholipid bilayer
without requiring a transport protein?
A. Sodium ion
B. Glucose
C. Large protein
D. Oxygen gas
Rationale: Small nonpolar molecules such as oxygen readily diffuse across
the lipid bilayer because they dissolve in its hydrophobic interior.
11. Passive transport differs from active transport because passive
transport:
A. Requires ATP.
B. Moves substances against their concentration gradient.
C. Does not require cellular energy.
D. Only transports ions.
Rationale: Passive transport relies on concentration gradients and does not
require ATP, whereas active transport uses energy to move substances
against gradients.
12. Diffusion is best defined as:
A. Movement of water through membranes only.
B. Net movement of molecules from higher to lower concentration.
and Function Exam Practice Questions
And Correct Answers (Verified Answers)
Plus Rationale 2026 Q&A| Instant
Download Pdf
1. Which structure is often called the "control center" of a eukaryotic cell
because it houses the genetic material and regulates cellular activities?
A. Ribosome
B. Nucleus
C. Lysosome
D. Golgi apparatus
Rationale: The nucleus contains DNA and controls gene expression, cell
growth, metabolism, and reproduction. It directs the synthesis of proteins
by regulating transcription.
2. Which organelle is primarily responsible for ATP production through
aerobic cellular respiration?
A. Chloroplast
B. Ribosome
C. Mitochondrion
D. Vacuole
,Rationale: Mitochondria generate ATP through the processes of the citric
acid cycle and oxidative phosphorylation, supplying energy for cellular
activities.
3. Ribosomes are the primary sites of:
A. DNA replication
B. Lipid synthesis
C. Protein synthesis
D. ATP storage
Rationale: Ribosomes translate mRNA into proteins by assembling amino
acids into polypeptide chains during translation.
4. Which organelle modifies, sorts, and packages proteins before they are
transported to their destinations?
A. Rough endoplasmic reticulum
B. Golgi apparatus
C. Smooth endoplasmic reticulum
D. Nucleus
Rationale: The Golgi apparatus receives proteins from the rough ER,
modifies them chemically, packages them into vesicles, and directs them to
specific cellular locations.
5. The smooth endoplasmic reticulum is primarily involved in:
A. DNA transcription
B. Protein translation
C. Lipid synthesis and detoxification
D. ATP production
Rationale: The smooth ER synthesizes lipids, metabolizes carbohydrates,
detoxifies harmful substances, and stores calcium ions.
, 6. Which organelle contains digestive enzymes that break down worn-out
organelles and cellular waste?
A. Peroxisome
B. Lysosome
C. Vacuole
D. Centriole
Rationale: Lysosomes contain hydrolytic enzymes capable of digesting
macromolecules, pathogens, and damaged cellular components.
7. Which cellular structure selectively regulates the movement of
substances into and out of the cell?
A. Cell wall
B. Plasma membrane
C. Cytoplasm
D. Nucleolus
Rationale: The plasma membrane is selectively permeable, allowing
specific molecules to cross while maintaining homeostasis.
8. According to the fluid mosaic model, the plasma membrane primarily
consists of:
A. Cellulose and proteins
B. Chitin and phospholipids
C. Phospholipids with embedded proteins
D. DNA and carbohydrates
Rationale: The plasma membrane is composed of a phospholipid bilayer
containing proteins, cholesterol, and carbohydrates that contribute to
membrane function.
9. Which component of the plasma membrane provides flexibility while
acting as a barrier to water-soluble substances?
, A. Cholesterol
B. Glycoproteins
C. Phospholipid bilayer
D. Cytoskeleton
Rationale: The phospholipid bilayer forms the structural foundation of the
membrane, with hydrophilic heads and hydrophobic tails creating selective
permeability.
10. Which molecule moves directly through the phospholipid bilayer
without requiring a transport protein?
A. Sodium ion
B. Glucose
C. Large protein
D. Oxygen gas
Rationale: Small nonpolar molecules such as oxygen readily diffuse across
the lipid bilayer because they dissolve in its hydrophobic interior.
11. Passive transport differs from active transport because passive
transport:
A. Requires ATP.
B. Moves substances against their concentration gradient.
C. Does not require cellular energy.
D. Only transports ions.
Rationale: Passive transport relies on concentration gradients and does not
require ATP, whereas active transport uses energy to move substances
against gradients.
12. Diffusion is best defined as:
A. Movement of water through membranes only.
B. Net movement of molecules from higher to lower concentration.
