WCU PHYS 261 MIDTERM EXAM 2026 – HUMAN PHYSIOLOGY TEST BANK WITH CORRECT ANSWERS & RATIONALES

WCU PHYS 261 MID-TERM EXAM NEWEST 2026
ACTUAL EXAM TEST BANK| PHYS 261 MIDTERM
EXAM REVIEW WITH COMPLETE 400 REAL EXAM
QUESTIONS AND CORRECT VERIFIED ANSWERS/
ALREADY GRADED A+ (MOST RECENT!!)
1. Which organelle is responsible for ATP production via
oxidative phosphorylation?

 A) Ribosome

 B) Golgi apparatus

 C) Mitochondrion

 D) Lysosome

Correct Answer: C) Mitochondrion
Rationale: Mitochondria are the "powerhouses" of the cell,
producing ATP through the electron transport chain and oxidative
phosphorylation.

2. Which transport process requires a carrier protein but does
NOT require direct ATP hydrolysis?

 A) Primary active transport

 B) Facilitated diffusion
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,  C) Simple diffusion

 D) Endocytosis

Correct Answer: B) Facilitated diffusion
Rationale: Facilitated diffusion uses carrier or channel proteins to
move substances down their concentration gradient without direct
ATP use.

3. The sodium-potassium pump (Na⁺/K⁺-ATPase) transports:

 A) 2 Na⁺ out, 3 K⁺ in

 B) 3 Na⁺ out, 2 K⁺ in

 C) 1 Na⁺ out, 1 K⁺ in

 D) 3 Na⁺ in, 2 K⁺ out

Correct Answer: B) 3 Na⁺ out, 2 K⁺ in
Rationale: The pump maintains the resting membrane potential
by exporting 3 sodium ions and importing 2 potassium ions per
ATP hydrolyzed.

4. If a cell is placed in a hypertonic solution, the cell will:

 A) Swell and possibly burst

 B) Shrink (crenate)

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,  C) Remain unchanged

 D) Actively transport water in

Correct Answer: B) Shrink (crenate)
Rationale: Water moves out of the cell into the hypertonic
extracellular fluid by osmosis, causing cell shrinkage.

5. The resting membrane potential of a typical neuron is
approximately:

 A) –70 mV

 B) +30 mV

 C) 0 mV

 D) –90 mV

Correct Answer: A) –70 mV
Rationale: The resting membrane potential is maintained by the
Na⁺/K⁺ pump and potassium leak channels, with the inside
negative relative to the outside.

6. Which ion has the highest permeability at rest in a neuron?

 A) Sodium (Na⁺)

 B) Potassium (K⁺)


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,  C) Calcium (Ca²⁺)

 D) Chloride (Cl⁻)

Correct Answer: B) Potassium (K⁺)
Rationale: At rest, potassium leak channels are open, making K⁺
the most permeable ion and the primary contributor to resting
membrane potential.

7. Which phase of an action potential is caused by the opening
of voltage-gated sodium channels?

 A) Depolarization (rising phase)

 B) Repolarization

 C) Hyperpolarization

 D) After-hyperpolarization

Correct Answer: A) Depolarization (rising phase)
Rationale: Influx of Na⁺ through voltage-gated Na⁺ channels
causes membrane potential to become positive (depolarization).

8. Repolarization of a neuron occurs due to:

 A) Opening of voltage-gated K⁺ channels and closing of
Na⁺ channels


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