Questions & Answers with rationales (Chapter 1-18) EXAM QUESTIONS
AND ANSWERS
1. Chapter 1 – Homeostasis
Which of the following best describes homeostasis?
A. Maintenance of a constant external environment
B. Elimination of all external stimuli
C. Dynamic balance in which internal conditions vary within narrow limits
D. Static internal equilibrium
✅ Answer: C
Rationale: Homeostasis is a dynamic process that maintains internal variables
within a narrow range despite external changes.
2. Chapter 2 – Chemical Composition
Which of the following bonds is the strongest in biological systems?
A. Hydrogen bond
B. Ionic bond
C. Covalent bond
D. Van der Waals interaction
✅ Answer: C
,Rationale: Covalent bonds involve shared electrons and are stronger than
hydrogen or ionic bonds in aqueous environments.
3. Chapter 3 – Cell Structure
The function of the rough endoplasmic reticulum is to:
A. Synthesize lipids
B. Detoxify substances
C. Synthesize proteins
D. Store calcium ions
✅ Answer: C
Rationale: The rough ER, studded with ribosomes, is primarily involved in protein
synthesis.
4. Chapter 4 – Enzymes and Energy
Enzymes function by:
A. Raising the activation energy
B. Lowering the activation energy
C. Being used up in reactions
D. Providing energy for reactions
✅ Answer: B
Rationale: Enzymes are biological catalysts that lower activation energy to speed
up reactions.
, 5. Chapter 5 – Membrane Transport
Which type of transport requires ATP?
A. Facilitated diffusion
B. Osmosis
C. Primary active transport
D. Simple diffusion
✅ Answer: C
Rationale: Primary active transport uses ATP to move substances against their
concentration gradient.
6. Chapter 6 – Communication & Integration
Which type of chemical messenger acts on the same cell that secreted it?
A. Endocrine
B. Paracrine
C. Autocrine
D. Neurotransmitter
✅ Answer: C
Rationale: Autocrine signals act on the cell that secretes them.
7. Chapter 7 – Neurons
Which ion primarily contributes to the resting membrane potential?
A. Calcium
B. Sodium