Biochemistry and Physiology Quiz 4

Question 1 of 20

1. Question

Edema and plasma proteins

(Circulation / Biological Compounds)

A patient with severe liver disease has very low plasma albumin. Which consequence is most directly expected?

Increased plasma oncotic pressure and hypertension

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Decreased plasma oncotic pressure and peripheral edema

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Increased interstitial hydrostatic pressure and dehydration

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Decreased capillary hydrostatic pressure and shock

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Question 2 of 20

2. Question

Chloride shift in RBCs

(Respiration / Membranes)

In systemic capillaries, CO₂ enters red blood cells and is converted to bicarbonate. What is the chloride shift?

Influx of chloride into RBCs as bicarbonate exits

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Efflux of chloride from RBCs while bicarbonate enters

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Exchange of chloride for sodium across the capillary wall

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Passive diffusion of chloride into plasma without coupling

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Question 3 of 20

3. Question

Hemoglobin–oxygen curve – right shift

(Respiration / Biological Compounds)

Which change causes a rightward shift of the hemoglobin–oxygen dissociation curve?

Decreased temperature

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Decreased 2,3-BPG

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Increased pCO₂ and H⁺

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Increased pH

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Question 4 of 20

4. Question

Competitive inhibition

(Metabolism / Enzyme Kinetics)

In competitive inhibition, how are Vmax and Km affected?

Vmax ↓, Km unchanged

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Vmax unchanged, Km ↑

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Vmax ↑, Km ↓

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Vmax ↑, Km unchanged

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Question 5 of 20

5. Question

Urea cycle defect

(Metabolism / Nitrogen)

A child with a urea-cycle enzyme deficiency is likely to present with:

Hemolytic anemia from lack of NADPH

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Hyperammonemia with neurologic symptoms

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Severe hypoglycemia only in fasting

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Defective collagen synthesis and scurvy

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Question 6 of 20

6. Question

Collagen triple helix formation

(Connective Tissue / Molecular Biology)

Formation of the collagen triple helix inside fibroblasts depends most on which amino acid modification?

Phosphorylation of serine

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Hydroxylation of proline and lysine

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Methylation of histidine

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Carboxylation of glutamate

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Question 7 of 20

7. Question

Resting membrane potential

(Membranes / Nervous System)

The resting membrane potential of neurons is mainly determined by:

Equilibrium potential of sodium

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Equilibrium potential of potassium and high K⁺ permeability at rest

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Equilibrium potential of calcium

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Equal permeability to Na⁺, K⁺, and Cl⁻

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Question 8 of 20

8. Question

Saltatory conduction

(Nervous System / Physiology)

Why do myelinated axons conduct action potentials faster than unmyelinated ones?

Myelin increases the number of voltage-gated Na⁺ channels

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Myelin decreases membrane resistance

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Myelin allows action potentials to “jump” between nodes of Ranvier

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Myelin increases intracellular Ca²⁺

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Question 9 of 20

9. Question

Length–tension in skeletal muscle

(Muscle Physiology)

Maximum active tension in skeletal muscle is generated when:

The muscle is extremely shortened with minimal overlap of filaments

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The muscle is excessively stretched with no overlap

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There is optimal overlap of actin and myosin allowing maximal cross-bridge formation

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ATP concentration is minimal

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Question 10 of 20

10. Question

Cardiac output and venous return

(Circulation)

All of the following increase venous return and cardiac output EXCEPT:

Skeletal muscle pump during exercise

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Sympathetic constriction of veins

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Sudden standing from supine without muscle activity

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Negative intrathoracic pressure during inspiration

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Question 11 of 20

11. Question

Alveolar ventilation

(Respiration)

Which change will increase alveolar ventilation most effectively?

Increasing tidal volume while keeping respiratory rate constant

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Increasing respiratory rate by shallow breathing

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Increasing dead space volume

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Decreasing tidal volume while increasing rate

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Question 12 of 20

12. Question

Renal clearance – freely filtered solute

(Renal Physiology)

A substance is freely filtered, not secreted or reabsorbed. Its clearance equals:

Zero

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Renal plasma flow

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Glomerular filtration rate (GFR)

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Urine flow rate

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Question 13 of 20

13. Question

Aldosterone effect

(Renal / Endocrines)

Aldosterone primarily acts on the distal nephron to:

Increase Na⁺ and water excretion

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Increase Na⁺ reabsorption and K⁺ secretion

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Decrease H⁺ secretion

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Increase glomerular filtration directly

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Question 14 of 20

14. Question

Salivary secretion – parasympathetic

(Oral Physiology / Digestion)

Parasympathetic stimulation of salivary glands generally causes:

Reduced blood flow and thick mucous saliva

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Increased blood flow and large volume of watery saliva

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No change in saliva but increased swallowing

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Inhibition of salivary secretion

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Question 15 of 20

15. Question

Gastric phase of digestion

(Digestion / Physiology)

Which stimulus primarily initiates the gastric phase of acid secretion?

Sight and smell of food

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Distension of the stomach and presence of peptides

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Entry of chyme into the duodenum

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Hypoglycemia

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Question 16 of 20

16. Question

Insulin’s metabolic actions

(Endocrines / Metabolism)

Which combination best describes insulin’s overall effects?

Increases glycogen breakdown, lipolysis, and gluconeogenesis

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Promotes glycogen, fat, and protein synthesis

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Decreases glucose uptake into muscle and adipose tissue

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Stimulates ketone body production

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Question 17 of 20

17. Question

Thyroid hormone and basal metabolic rate

(Endocrines / Metabolism)

A patient with hyperthyroidism will typically show which change?

Decreased basal metabolic rate and cold intolerance

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Increased basal metabolic rate and weight loss

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Decreased heart rate and constipation

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Hyporeflexia and lethargy

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Question 18 of 20

18. Question

Vitamin K and coagulation

(Biological Compounds / Liver Physiology)

Vitamin K is required for:

Hydroxylation of proline in collagen

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Carboxylation of glutamate residues in clotting factors II, VII, IX, and X

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Phosphorylation of glycogen synthase

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Activation of intrinsic factor

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Question 19 of 20

19. Question

Oral fluid buffering

(Oral Physiology / Acid–Base)

Which salivary component contributes most to buffering oral acids produced by bacteria?

Amylase

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Bicarbonate ion

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Lysozyme

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Mucins

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Question 20 of 20

20. Question

Calcium homeostasis – PTH

(Endocrines / Renal & Bone)

Parathyroid hormone (PTH) increases plasma Ca²⁺ mainly by:

Decreasing osteoclast activity

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Increasing renal Ca²⁺ reabsorption and stimulating bone resorption

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Decreasing 1,25-(OH)₂ vitamin D formation

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Increasing urinary Ca²⁺ excretion

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Biochemistry and Physiology Quiz 4

Quiz Summary

Information

Results

Results

Categories

1. Question

2. Question

3. Question

4. Question

5. Question

Urea cycle defect

6. Question

Collagen triple helix formation

7. Question

Resting membrane potential

8. Question

Saltatory conduction

9. Question

Length–tension in skeletal muscle

10. Question

Cardiac output and venous return

11. Question

Alveolar ventilation

12. Question

Renal clearance – freely filtered solute

13. Question

Aldosterone effect

14. Question

Salivary secretion – parasympathetic

15. Question

Gastric phase of digestion

16. Question

Insulin’s metabolic actions

17. Question

Thyroid hormone and basal metabolic rate

18. Question

Vitamin K and coagulation

19. Question

Oral fluid buffering

20. Question

Calcium homeostasis – PTH