,CHAPTER 1 — CELLULAR FUNCTION b r br br b r
Question1 — (energyproduction) b
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Which organelle is the primary site of aerobic ATP production via oxidative phosphor
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ylation?
A. Smooth endoplasmic reticulum br br
B. Mitochondrion
C. Ribosome
D. Lysosome
Correct answer: B. Mitochondrion Rationa
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le:
Mitochondria generate the majority of cellular ATP byoxidative phosphorylation
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(electron transport chain + chemiosmosis) in the presence of oxygen.
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A is incorrect —
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smoothER is involved in lipid synthesis and detoxification, n
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ot major ATP production.
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C is incorrect — ribosomes synthesize proteins.
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D is incorrect —
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lysosomes digest macromolecules and damaged organelles but do not produc
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e ATP.br
Question2 — Membrane transport rb br br br
A patient receives an IV drug that must enter cells against a concentration gradient. Wh
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ich transport mechanism is most likely responsible?
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A. Simple diffusion through the lipid bilayer
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B. Facilitated diffusion through a channel protein br br br br br
C. Primary active transport using ATP (e.g., Na⁺/K⁺-ATPase)
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D. Osmosis
Correct answer: C. Primary active transport using ATP (e.g., Na⁺/K⁺-
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ATPase) Rationale: br
Movement against a concentration gradient requires energy input; primary active
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transport directly uses ATP (or an ATPase) to pump ions or molecules.
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A and B are passive (do not move substances uphill).
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, D (osmosis)is passive movement of water across a semipermeable m
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embrane down its gradient. br br br
Question3 — Facilitateddiffusion example rb br br rb br
Glucose entry into skeletal muscle during resting conditions (no insulin present) predominantly
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occurs by:
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A. Simple diffusion through the membrane br br br br
B. Facilitated diffusion via GLUT transporters (down its concentration gradient)
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C. Active transport by Na⁺/glucose cotransporterrequiring ATP
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D. Endocytosis
Correct answer: B. Facilitateddiffusion via GLUT transporters Rat
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ionale:
Glucose crosses membranes via GLUT transporters (carrier proteins) by facilitated diff
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usion when no energy is required and transport follows the concentration gradient.
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A is incorrect — glucose is polar and cannot pass bysimple diffusion.
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C (Na⁺/glucose cotransport)is used in some epithelia (e.g., intestinal/renal) a
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nd is secondaryactive, not the predominant mechanism in resting muscle.
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D is incorrect —
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endocytosis is not the routine mechanism for glucose uptake.
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Question4 — Osmotic effects on red blood cells
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A patient’s red blood cells placed in a hypertonic IV solution will:
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A. Swell and potentially lyse (hemolysis)
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B. Shrink (crenate) as water leaves the cell br br br br br br
C. Remain unchanged because RBC membranes are impermeable to water
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D. Gain sodiumvia active transport and maintain size
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Correct answer: B. Shrink (crenate) as water leaves the cell Rationa
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le:
In a hypertonic environment, extracellular osmolarity is higher than intracellular;
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water moves out of the cell by osmosis,causing cell shrinkage (crenation).
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, A is what happens in hypotonic solutions (water moves in).
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C is false — water crosses membranes rapidly (aquaporins).
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D is incorrect — acute sodiumpumping cannot prevent osmotic water shifts.
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Question5 — Cellular adaptation(definitions)
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Which term best describes an increase in cell size (e.g., cardiac myocytes enlarging fro
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m chronic pressure overload)?
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A. Hyperplasia
B. Atrophy
C. Hypertrophy
D. Metaplasia
Correctanswer:C. Hypertrophy Rationale:
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Hypertrophy = increase in cell size (often with increased functional capacity). For
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example, cardiac myocyte hypertrophy occurs with chronic increased workload.
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A (hyperplasia) = increase in cell number.
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B (atrophy) = decrease in cell size and/or number.
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D (metaplasia) = replacement of one adult cell type with another (adaptive ch
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ange).
Question6 — Apoptosis vs necrosis rb br br br br
Which statement correctly distinguishes apoptosis fromnecrosis?
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A. Apoptosis is an inflammatory, uncontrolled cell death; necrosis is programmed a
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nd energy-dependent.
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B. Apoptosis is energy-dependent, orderly, and typically non-
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inflammatory; necrosis causes membrane rupture and inflammation.
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C. Apoptosis only occurs in responseto infection; necrosis only occurs with is
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chemia.
D. Apoptosis always leads to tissue scarring; necrosis never does.
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Correctanswer: B. Apoptosis is energy-dependent, orderly, and typically non-
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inflammatory; necrosis causes membrane rupture and inflammation.
br br br br br b r br
Question1 — (energyproduction) b
r br br b
r
Which organelle is the primary site of aerobic ATP production via oxidative phosphor
br br br br br br br br br br br br
ylation?
A. Smooth endoplasmic reticulum br br
B. Mitochondrion
C. Ribosome
D. Lysosome
Correct answer: B. Mitochondrion Rationa
br br br br
le:
Mitochondria generate the majority of cellular ATP byoxidative phosphorylation
br br br b r br b r br br br
(electron transport chain + chemiosmosis) in the presence of oxygen.
br br br br br br br br br
A is incorrect —
br br br
smoothER is involved in lipid synthesis and detoxification, n
br br br br br br br br br b r
ot major ATP production.
br br br
C is incorrect — ribosomes synthesize proteins.
br br br br br br
D is incorrect —
br br br
lysosomes digest macromolecules and damaged organelles but do not produc
br br br br br br br br br br
e ATP.br
Question2 — Membrane transport rb br br br
A patient receives an IV drug that must enter cells against a concentration gradient. Wh
br br br br br br br br br br br br br br
ich transport mechanism is most likely responsible?
br br br br br b r
A. Simple diffusion through the lipid bilayer
br br br br br
B. Facilitated diffusion through a channel protein br br br br br
C. Primary active transport using ATP (e.g., Na⁺/K⁺-ATPase)
br br br br br br
D. Osmosis
Correct answer: C. Primary active transport using ATP (e.g., Na⁺/K⁺-
br br br br br br b r br br
ATPase) Rationale: br
Movement against a concentration gradient requires energy input; primary active
br br br br br br br br br
transport directly uses ATP (or an ATPase) to pump ions or molecules.
br br br br br br br br br br br
A and B are passive (do not move substances uphill).
br br br br br br br br br
, D (osmosis)is passive movement of water across a semipermeable m
br br br br br br br br br br
embrane down its gradient. br br br
Question3 — Facilitateddiffusion example rb br br rb br
Glucose entry into skeletal muscle during resting conditions (no insulin present) predominantly
br br br br br br br br br br br b
occurs by:
r br
A. Simple diffusion through the membrane br br br br
B. Facilitated diffusion via GLUT transporters (down its concentration gradient)
br br br br br br br br
C. Active transport by Na⁺/glucose cotransporterrequiring ATP
br br br br br br
D. Endocytosis
Correct answer: B. Facilitateddiffusion via GLUT transporters Rat
br br br br br br br br
ionale:
Glucose crosses membranes via GLUT transporters (carrier proteins) by facilitated diff
br br br br br br br br br br
usion when no energy is required and transport follows the concentration gradient.
br br br br br br br br br br br
A is incorrect — glucose is polar and cannot pass bysimple diffusion.
br br br br br br br br br br br br
C (Na⁺/glucose cotransport)is used in some epithelia (e.g., intestinal/renal) a
br br br br br br br b r br br
nd is secondaryactive, not the predominant mechanism in resting muscle.
br br br br br br br br br br
D is incorrect —
br br br
endocytosis is not the routine mechanism for glucose uptake.
br br br br br br br br br
Question4 — Osmotic effects on red blood cells
b
r br br br br br br br
A patient’s red blood cells placed in a hypertonic IV solution will:
br br br br br br br br br br br
A. Swell and potentially lyse (hemolysis)
br br br br
B. Shrink (crenate) as water leaves the cell br br br br br br
C. Remain unchanged because RBC membranes are impermeable to water
br br br br br br b r br
D. Gain sodiumvia active transport and maintain size
br br br br br br b r
Correct answer: B. Shrink (crenate) as water leaves the cell Rationa
br br br br br br br br b r br
le:
In a hypertonic environment, extracellular osmolarity is higher than intracellular;
br br br br b r br br br br
water moves out of the cell by osmosis,causing cell shrinkage (crenation).
br br br br br br br br br br br
, A is what happens in hypotonic solutions (water moves in).
br br br br br br br br br
C is false — water crosses membranes rapidly (aquaporins).
br br br br br br br br
D is incorrect — acute sodiumpumping cannot prevent osmotic water shifts.
br br br br br br br br br br br
Question5 — Cellular adaptation(definitions)
rb br br br rb
Which term best describes an increase in cell size (e.g., cardiac myocytes enlarging fro
br br br br br br br br br br br br br
m chronic pressure overload)?
br br br
A. Hyperplasia
B. Atrophy
C. Hypertrophy
D. Metaplasia
Correctanswer:C. Hypertrophy Rationale:
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Hypertrophy = increase in cell size (often with increased functional capacity). For
br br br br br br br br br br br
example, cardiac myocyte hypertrophy occurs with chronic increased workload.
br br br br br br br br
A (hyperplasia) = increase in cell number.
br br br br br br
B (atrophy) = decrease in cell size and/or number.
br br br br br br br br
D (metaplasia) = replacement of one adult cell type with another (adaptive ch
br br br br br br br br br br br br
ange).
Question6 — Apoptosis vs necrosis rb br br br br
Which statement correctly distinguishes apoptosis fromnecrosis?
br b r br b r br br
A. Apoptosis is an inflammatory, uncontrolled cell death; necrosis is programmed a
br br br b r br br br br br br
nd energy-dependent.
br
B. Apoptosis is energy-dependent, orderly, and typically non-
br br br br br b r
inflammatory; necrosis causes membrane rupture and inflammation.
br br br b r br br
C. Apoptosis only occurs in responseto infection; necrosis only occurs with is
br br br br br br b r br br br br
chemia.
D. Apoptosis always leads to tissue scarring; necrosis never does.
br br br br br br br br
Correctanswer: B. Apoptosis is energy-dependent, orderly, and typically non-
br br br br br br br br br
inflammatory; necrosis causes membrane rupture and inflammation.
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