Basic life processes and homeostasis MCQs With Answer

Mastering basic life processes and homeostasis is essential for B.Pharm students preparing for pharmacology, physiology and therapeutics. This collection of focused MCQs with answers covers cell physiology, membrane transport, diffusion, osmosis, active transport, enzyme kinetics, cellular respiration, ATP synthesis, metabolic pathways, fluid–electrolyte balance, acid–base regulation, hormonal control and feedback mechanisms that sustain internal stability. Questions emphasize biochemical and physiological mechanisms, clinical relevance and drug–body interactions to deepen understanding beyond memorization. Designed to build analytical skills for exams and pharmaceutical practice, these items integrate molecular detail with systemic homeostasis. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which phospholipid is the most abundant in the outer leaflet of the eukaryotic plasma membrane?

• Phosphatidylcholine
• Sphingomyelin
• Phosphatidylserine
• Phosphatidylethanolamine

Correct Answer: Phosphatidylcholine

Q2. The resting membrane potential of most excitable cells is primarily determined by which factor?

• High K+ permeability through leak channels
• Persistent opening of voltage-gated Na+ channels
• Equal distribution of all ions across the membrane
• Active transport of Ca2+ into the cell

Correct Answer: High K+ permeability through leak channels

Q3. Secondary active transport across the cell membrane uses energy supplied by:

• ATP hydrolysis directly by the transporter
• An electrochemical gradient generated by primary active transport
• Endocytosis of the solute
• Passive diffusion down a concentration gradient

Correct Answer: An electrochemical gradient generated by primary active transport

Q4. What is the rate-limiting enzyme of glycolysis that is allosterically regulated by AMP and ATP?

• Hexokinase
• Phosphofructokinase-1 (PFK-1)
• Pyruvate kinase
• Phosphoglycerate kinase

Correct Answer: Phosphofructokinase-1 (PFK-1)

Q5. What is the net ATP yield from anaerobic glycolysis per molecule of glucose?

• 2 ATP
• 4 ATP
• 36 ATP
• 38 ATP

Correct Answer: 2 ATP

Q6. Which organ is the primary site for gluconeogenesis during fasting?

• Liver
• Skeletal muscle
• Brain
• Adipose tissue

Correct Answer: Liver

Q7. In the mitochondrial electron transport chain, which complex transfers electrons to molecular oxygen (the final electron acceptor)?

• Complex I (NADH dehydrogenase)
• Complex II (succinate dehydrogenase)
• Complex III (cytochrome bc1)
• Complex IV (cytochrome c oxidase)

Correct Answer: Complex IV (cytochrome c oxidase)

Q8. Which buffer system is the most important for acid–base balance in extracellular fluid (plasma)?

• Bicarbonate (HCO3−) buffer system
• Phosphate buffer system
• Hemoglobin buffer system
• Protein buffer system

Correct Answer: Bicarbonate (HCO3−) buffer system

Q9. The Henderson–Hasselbalch equation relates pH to which two parameters?

• pKa and the ratio of conjugate base to acid
• Temperature and pressure
• Enzyme concentration and substrate concentration
• Partial pressure of oxygen and carbon dioxide

Correct Answer: pKa and the ratio of conjugate base to acid

Q10. A patient with metabolic acidosis typically exhibits which immediate compensatory respiratory change?

• Increased ventilation (hyperventilation) to lower PaCO2
• Decreased ventilation to retain CO2
• No change in ventilation
• Intermittent apnea

Correct Answer: Increased ventilation (hyperventilation) to lower PaCO2

Q11. Aldosterone acts on the distal nephron to produce which effect?

• Increase Na+ reabsorption and K+ secretion
• Increase renal glucose reabsorption
• Decrease water reabsorption by inhibiting aquaporins
• Stimulate parathyroid hormone release

Correct Answer: Increase Na+ reabsorption and K+ secretion

Q12. Which stimulus is the primary physiological trigger for insulin secretion from pancreatic β-cells?

• Elevated blood glucose concentration
• Low blood glucose concentration
• High circulating glucagon
• Fasting ketone bodies

Correct Answer: Elevated blood glucose concentration

Q13. Glucagon primarily increases blood glucose by which hepatic actions?

• Stimulating glycogenolysis and gluconeogenesis
• Enhancing insulin secretion
• Promoting muscle glucose uptake
• Inhibiting lipolysis in adipose tissue

Correct Answer: Stimulating glycogenolysis and gluconeogenesis

Q14. Which hormone directly lowers blood calcium levels by inhibiting osteoclast activity?

• Calcitonin
• Parathyroid hormone (PTH)
• Calcitriol (active vitamin D)
• Aldosterone

Correct Answer: Calcitonin

Q15. What is the major intracellular cation that determines cell osmolarity and membrane potential?

• Potassium (K+)
• Sodium (Na+)
• Calcium (Ca2+)
• Chloride (Cl−)

Correct Answer: Potassium (K+)

Q16. What is the approximate osmolarity of 0.9% (w/v) NaCl isotonic saline?

• 154 mM NaCl (~308 mOsm/L)
• 308 mM NaCl (~616 mOsm/L)
• 0.9 mOsm/L
• 77 mOsm/L

Correct Answer: 154 mM NaCl (~308 mOsm/L)

Q17. Which type of cell junction provides electrical coupling between cardiac myocytes for rapid impulse conduction?

• Gap junctions
• Tight junctions
• Desmosomes
• Adherens junctions

Correct Answer: Gap junctions

Q18. The Na+/K+ ATPase pumps how many sodium and potassium ions per ATP hydrolyzed?

• 3 Na+ out and 2 K+ in
• 2 Na+ out and 3 K+ in
• 1 Na+ out and 1 K+ in
• 3 K+ out and 2 Na+ in

Correct Answer: 3 Na+ out and 2 K+ in

Q19. Which vitamin is a required cofactor for carboxylase enzymes involved in gluconeogenesis and fatty acid synthesis?

• Biotin (vitamin B7)
• Thiamine (vitamin B1)
• Niacin (vitamin B3)
• Riboflavin (vitamin B2)

Correct Answer: Biotin (vitamin B7)

Q20. Which metabolic process occurs primarily in mitochondria rather than the cytosol?

• Glycolysis
• Fatty acid β‑oxidation
• Pentose phosphate pathway
• Protein translation on rough ER ribosomes

Correct Answer: Fatty acid β‑oxidation

Q21. Which enzyme converts angiotensin I to the potent vasoconstrictor angiotensin II?

• Angiotensin-converting enzyme (ACE)
• Renin
• Aldosterone synthase
• Angiotensinogen

Correct Answer: Angiotensin-converting enzyme (ACE)

Q22. Negative feedback in physiological homeostasis means:

• The response opposes the initial change to maintain stability
• The response amplifies the initial change
• The system stops responding entirely
• The response is always pathological

Correct Answer: The response opposes the initial change to maintain stability

Q23. The Bohr effect describes how which factors lower hemoglobin’s affinity for O2?

• Decreased pH and increased CO2
• Increased pH and decreased CO2
• Decreased temperature and decreased 2,3-BPG
• High oxygen partial pressure

Correct Answer: Decreased pH and increased CO2

Q24. Tonicity of a solution, relevant to cell volume changes, depends mainly on:

• Concentration of non-penetrating (impermeant) solutes
• Total osmolarity including penetrating solutes
• pH of the solution
• Temperature of the solution

Correct Answer: Concentration of non-penetrating (impermeant) solutes

Q25. Activation of which receptor subtype is classically coupled to Gs and increases intracellular cAMP?

• β1-adrenergic receptor
• α2-adrenergic receptor
• M2 muscarinic receptor
• GABA_B receptor

Correct Answer: β1-adrenergic receptor

Q26. Which innate immune receptors detect conserved pathogen-associated molecular patterns (PAMPs)?

• Toll-like receptors (TLRs)
• Major histocompatibility complex (MHC) molecules
• B-cell receptors (BCRs)
• T-cell receptors (TCRs)

Correct Answer: Toll-like receptors (TLRs)

Q27. During the neuronal action potential, which ionic movement is chiefly responsible for repolarization?

• Efflux of K+ through voltage-gated K+ channels
• Influx of Na+ through voltage-gated Na+ channels
• Influx of Ca2+ through voltage-gated Ca2+ channels
• Influx of Cl− through GABA-activated channels

Correct Answer: Efflux of K+ through voltage-gated K+ channels

Q28. A rightward shift of the oxygen-hemoglobin dissociation curve (reduced O2 affinity) is caused by:

• Increased 2,3‑bisphosphoglycerate (2,3‑BPG) concentration
• Decreased temperature
• Alkalosis (increased pH)
• Decreased CO2

Correct Answer: Increased 2,3‑bisphosphoglycerate (2,3‑BPG) concentration

Q29. Which hormone primarily increases basal metabolic rate by stimulating oxygen consumption and heat production?

• Thyroxine (T4)
• Insulin
• Glucagon
• Aldosterone

Correct Answer: Thyroxine (T4)

Q30. The major intracellular buffer system that helps maintain pH inside most cells is:

• Intracellular proteins (including hemoglobin in erythrocytes)
• Extracellular bicarbonate only
• Plasma phosphate exclusively
• Inhaled CO2 removed by the lungs

Correct Answer: Intracellular proteins (including hemoglobin in erythrocytes)

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com