FCPS Part 1 Medicine MCQs by Subject: Physiology, Biochemistry & Microbiology

Sample FCPS Part 1 Medicine MCQs from Physiology, Biochemistry and Microbiology — three large subjects not yet covered by our Anatomy/Pathology/Pharmacology round-up — each with a full explanation.

Alongside Anatomy, Pathology and Pharmacology, HighYield's Medicine question bank also draws heavily on Physiology, Biochemistry and Microbiology — three subjects that don't yet have dedicated practice coverage. Below is a sample across all three.

Physiology

1. The Frank–Starling mechanism states that, within physiological limits, an increase in venous return (and hence ventricular end-diastolic volume) leads to:

A) Decreased stroke volume
B) Increased stroke volume due to increased myocardial fibre stretch ✅
C) No change in stroke volume
D) Decreased heart rate only

2. A rightward shift of the oxygen–haemoglobin dissociation curve (e.g. with increased CO2, decreased pH, or increased temperature) results in:

A) Increased haemoglobin affinity for oxygen
B) Decreased haemoglobin affinity for oxygen, facilitating O2 release to tissues ✅
C) No change in oxygen affinity
D) Increased oxygen-carrying capacity

3. Renal blood flow and GFR remain relatively constant across a wide range of systemic blood pressures mainly due to:

A) Autoregulation via myogenic and tubuloglomerular feedback mechanisms ✅
B) Sympathetic stimulation alone
C) Antidiuretic hormone action
D) Aldosterone secretion

Biochemistry

4. The rate-limiting enzyme of glycolysis, which catalyses the committed step of converting fructose-6-phosphate to fructose-1,6-bisphosphate, is:

A) Hexokinase
B) Phosphofructokinase-1 ✅
C) Pyruvate kinase
D) Aldolase

5. The urea cycle, which converts toxic ammonia into urea for excretion, takes place primarily in the:

A) Kidney
B) Liver ✅
C) Muscle
D) Brain

6. Under anaerobic conditions, pyruvate is converted to lactate by lactate dehydrogenase primarily to:

A) Produce ATP directly
B) Regenerate NAD+ so glycolysis can continue ✅
C) Enter the citric acid cycle
D) Synthesise glucose

Microbiology

7. The presence of HBsAg together with IgM anti-HBc in a patient's serum is most consistent with:

A) Chronic hepatitis B with past exposure
B) Acute hepatitis B infection ✅
C) Successful vaccination
D) Resolved hepatitis B infection

8. Tetanospasmin, the exotoxin produced by Clostridium tetani, causes muscle spasm by:

A) Blocking acetylcholine release at the neuromuscular junction
B) Blocking release of inhibitory neurotransmitters (GABA and glycine) in the spinal cord ✅
C) Directly stimulating motor neurons
D) Destroying myelin sheaths

9. Mycobacterium tuberculosis is best visualised on a sputum smear using which staining technique, owing to its lipid-rich cell wall?

A) Gram stain
B) Ziehl–Neelsen (acid-fast) stain ✅
C) Giemsa stain
D) India ink stain

Why These Subjects Still Matter

Physiology, Biochemistry and Microbiology are tested at FCPS Part 1 depth — integrated with clinical medicine scenarios rather than asked as isolated MBBS-level recall.

HighYield's FCPS Part 1 Medicine and Allied question bank covers every subject in the paper, each question explained. See our Anatomy, Pathology & Pharmacology MCQs post for the other three, or check the most repeated FCPS Part 1 Medicine MCQs to prioritise your revision. Try the first 20 questions free, no sign-in required.