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Block 2 — Biochemistry MCQs
UHS · 427 MCQs with clinical pearls · Prof Jariya
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Sections in this uhs
- Amino Acid Carbon Skeletons — 80 MCQs
- Urea Cycle — 27 MCQs
- Protein Digestion — 23 MCQs
- Protein Digestion and Absorption — 21 MCQs
- One Carbon Metabolism — 19 MCQs
- Glycosaminoglycans — 18 MCQs
- Collagen — 18 MCQs
- Carbohydrate Classification — 16 MCQs
- Collagen Disorders — 15 MCQs
- TCA Cycle — 14 MCQs
- Collagen Structure — 12 MCQs
- Amino Acid Transport — 12 MCQs
- AAT Deficiency — 11 MCQs
- Mucopolysaccharidoses — 10 MCQs
Sample MCQs with clinical pearls
A biochemist studying collagen notes that procollagen is synthesised as a precursor with extra peptides at both ends. These extra peptides are called:
A) Propeptides ✔
B) Signal peptides
C) Telopeptides
D) Tripeptides
E) Zymopeptides
Procollagen = soluble precursor with N and C-terminal propeptides. Propeptides: (1) prevent intracellular fibril assembly, (2) guide correct chain registration. After secretion: procollagen N/C-proteinase cleavage → tropocollagen → fibril assembly → crosslinking by lysyl oxidase → mature collagen.
A 15-year-old OI patient has a mutation replacing glycine in the Gly-X-Y repeat of type I collagen. Which type of side chain replacing glycine would be LEAST likely to disrupt the triple helix?
A) Acidic side chain
B) Bulky side chain
C) Non-polar side chain
D) Polar side chain
E) Small side chain ✔
Glycine has the smallest possible side chain (single H atom) essential to fit inside the cramped triple helix centre. Replacement with any bulky side chain blocks triple helix formation. A small side chain replacement causes least disruption. Severity of OI correlates with bulkiness of substituting amino acid.
A 4-year-old boy with skin hyperextensibility, joint hypermobility, and easy bruising has a collagen type V mutation. Type V collagen is important because it regulates fibrillogenesis of:
A) Collagen type I and III ✔
B) Collagen type II and IV
C) Collagen type II and VI
D) Collagen type III and IV
E) Collagen type IV and VII
Type V collagen nucleates and regulates fibril diameter of type I and III collagen. Collagen V mutation → disorganised type I/III fibrils → weakened skin (hyperextensibility) and joint capsules/tendons (hypermobility) = Ehlers-Danlos Syndrome classic type.
427 MCQs are arranged to the learning outcomes of this uhs.
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