ICAR AIEEA (PG): Master's entrance, Veterinary Science and Animal Sciences · India · NTA for ICAR
Original practice questions written to the published syllabus · not past papersBiomolecules, enzymes and the metabolic pathways that turn feed into energy, milk, meat and eggs, including the ruminant's special dependence on volatile fatty acids and gluconeogenesis.
In the exams: ICAR AICE-JRF core group 08; ICAR AIEEA-PG 12 (Veterinary Biochemistry); China basic paper 12
ICAR AIEEA (PG), Animal Biotechnology group (Veterinary Biochemistry)
Enzyme kinetics and inhibition, metabolic pathway enzymes and their cofactors, regulation points, ATP yields, vitamin coenzyme roles, nucleic acid structure and molecular techniques.
How our questions for ICAR AIEEA spread across the units of Veterinary Biochemistry. Difficulty: 3 easy, 32 medium, 3 hard.
| Enzymes and enzyme kinetics | 5 | |
| Lipid metabolism | 5 | |
| Ruminant metabolism: volatile fatty acids, gluconeogenesis and ketogenesis | 5 | |
| Biomolecules and their interactions | 4 | |
| Carbohydrate metabolism | 4 | |
| Protein and amino-acid metabolism | 3 | |
| Vitamins: biochemical roles | 3 | |
| Nucleic acids | 2 | |
| Hormones | 2 | |
| Cell signalling | 2 | |
| Biochemical laboratory techniques | 2 | |
| Minerals: biochemical roles | 1 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
Complete aerobic oxidation of one glucose yields about 30 ATP rather than 32 when cytosolic NADH enters mitochondria by which route?
A. The glycerol-3-phosphate shuttle
The glycerol-3-phosphate shuttle passes electrons to FAD, giving 1.5 ATP per cytosolic NADH instead of 2.5, so the two glycolytic NADH give 2 fewer ATP. The malate-aspartate shuttle preserves NADH, giving 32. The carnitine shuttle moves acyl groups.
Further reading: Nelson DL, Cox MM, Lehninger Principles of Biochemistry, 8th ed.
Which enzyme catalyses the committed, biotin-dependent step of de novo fatty acid synthesis?
A. Acetyl-CoA carboxylase
Acetyl-CoA carboxylase makes malonyl-CoA and is activated by citrate and insulin and inhibited by AMPK. Pyruvate carboxylase is also biotin-dependent but serves gluconeogenesis; fatty acid synthase comes after; ATP-citrate lyase supplies cytosolic acetyl-CoA.
Further reading: Nelson DL, Cox MM, Lehninger Principles of Biochemistry, 8th ed.
Which enzyme requires biotin?
B. Propionyl-CoA carboxylase
Biotin is the carboxyl carrier for carboxylases: pyruvate, acetyl-CoA and propionyl-CoA carboxylase. Pyruvate dehydrogenase and transketolase use TPP; glutamate dehydrogenase uses NAD(P).
Further reading: Nelson DL, Cox MM, Lehninger Principles of Biochemistry, 8th ed.
Total serum calcium in a cow is reported as 10 mg/dL. What is this in mmol/L (atomic mass of calcium 40.08)?
D. 2.50 mmol/L
10 mg/dL = 100 mg/L; 100 / 40.08 = 2.50 mmol/L. 0.25 forgets the dL-to-L factor of 10; 5.0 is the value in mEq/L (calcium is divalent, so mEq/L = 2 x mmol/L); 1.25 halves the correct value instead of doubling it.
Further reading: Nelson DL, Cox MM, Lehninger Principles of Biochemistry, 8th ed.
Which pair of vitamins is required to convert propionate to succinyl-CoA?
A. Biotin and vitamin B12
Biotin serves propionyl-CoA carboxylase and adenosylcobalamin (B12) serves methylmalonyl-CoA mutase. Coenzyme A (from pantothenate) is also involved, but the pathway-specific vitamins are biotin and B12.
Further reading: Nelson DL, Cox MM, Lehninger Principles of Biochemistry, 8th ed.
A cow produces 30 kg milk per day containing 4.8% lactose (molar mass 342.3 g/mol). How much glucose (180.16 g/mol) is needed for lactose synthesis alone?
C. About 1.52 kg
Lactose = 30 x 0.048 = 1.44 kg = 1440/342.3 = 4.21 mol. Each lactose needs two glucose (one becomes galactose), so 8.41 mol x 180.16 = 1516 g, about 1.52 kg. 0.76 kg counts one glucose per lactose; 1.44 kg equates the mass of lactose with glucose; 3.03 kg doubles again.
Further reading: Nelson DL, Cox MM, Lehninger Principles of Biochemistry, 8th ed.
Ten here, 38 in the app. The Laisha app has every practice question we have written to ICAR AIEEA in this subject, marked as you go, with timed papers, a jump-to-unanswered list and a certificate when you pass at 70 per cent.
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