NLE Biochemistry & Forensic Medicine MCQs: Practice Questions With Explanations

Sample NLE (NRE) MCQs from Biochemistry and Forensic Medicine — together 193 questions in HighYield's NLE bank without a dedicated practice post until now — covering core metabolic pathways and postmortem findings, each with the correct answer explained.

Biochemistry and Forensic Medicine together make up 193 questions in HighYield's NLE bank (107 and 86 questions respectively) — both shared basic-sciences subjects that are easy to deprioritise in favour of clinical subjects, but still directly tested. Below is a sample set of Biochemistry and Forensic Medicine MCQs in the same one-line format as the full bank.

Biochemistry

1. The rate-limiting enzyme of glycolysis, allosterically inhibited by ATP and citrate, is:

A) Hexokinase
B) Phosphofructokinase-1 ✅
C) Pyruvate kinase
D) Glucose-6-phosphate dehydrogenase

2. The rate-limiting enzyme of hepatic cholesterol synthesis, and the target of statin drugs, is:

A) HMG-CoA reductase ✅
B) HMG-CoA synthase
C) Acetyl-CoA carboxylase
D) Squalene epoxidase

3. The first, rate-limiting step of the urea cycle, occurring in the mitochondria, is catalysed by:

A) Ornithine transcarbamylase
B) Carbamoyl phosphate synthetase I ✅
C) Argininosuccinate synthetase
D) Arginase

4. Deficiency of vitamin B12 classically causes megaloblastic anaemia together with which neurological complication?

A) Peripheral neuropathy only
B) Subacute combined degeneration of the spinal cord ✅
C) Guillain-Barré syndrome
D) Wernicke encephalopathy

5. Impaired hydroxylation of proline and lysine during collagen synthesis, leading to bleeding gums and poor wound healing, is the underlying defect in:

A) Scurvy (vitamin C deficiency) ✅
B) Rickets (vitamin D deficiency)
C) Pellagra (niacin deficiency)
D) Beriberi (thiamine deficiency)

Forensic Medicine

6. Postmortem lividity (livor mortis) results from the gravitational settling of blood in dependent parts and is commonly cited in forensic texts as becoming fixed (non-blanching) at approximately:

A) 1–2 hours after death
B) 8–12 hours after death ✅
C) 24 hours after death
D) It never fixes

7. Rigor mortis classically appears first in the small muscles of the face and jaw before generalising to larger muscle groups, because these muscles:

A) Have a lower muscle mass and ATP content ✅
B) Have a richer blood supply
C) Contain more slow-twitch fibres
D) Are innervated by the vagus nerve

8. An oblique, incomplete ligature mark above the level of the thyroid cartilage, with the point of suspension away from the mark, is typical of death by:

A) Ligature strangulation
B) Hanging ✅
C) Manual strangulation
D) Smothering

9. A wound with clean, sharply-cut edges, no bridging of tissue strands across the wound, and minimal bruising of the margins is best described as:

A) A lacerated wound
B) An incised wound ✅
C) An abrasion
D) A contusion

10. Estimating the age of a skeletal or decomposed body by assessing the fusion status of the epiphyses and ossification centres is most useful in:

A) Adults over 40 years
B) Children and young adults under skeletal maturity ✅
C) Neonates only
D) It cannot be used for age estimation

Why These Deserve Dedicated Revision

Biochemistry and Forensic Medicine don't carry the same weight as Surgery or General Medicine on the NLE theory paper, but the exam's 60% pass mark is calculated across the whole paper rather than per subject — so a gap in a smaller basic-science subject costs exactly as much as one in a bigger clinical one.

HighYield's NLE question bank covers Biochemistry and Forensic Medicine alongside every other discipline on the theory paper, with every question explained. Start with your first questions free, no sign-in required.