Last Day Revision – FCPS Part 1

MCQ Tips — Must Memorize

MCQ clue	Answer
Night blindness	Vitamin A deficiency
Rickets / osteomalacia	Vitamin D deficiency
Hemolysis with neurologic dysfunction	Vitamin E deficiency
Prolonged PT due to defective clotting-factor carboxylation	Vitamin K deficiency
Wernicke–Korsakoff syndrome	Vitamin B1 deficiency
Pellagra: dermatitis, diarrhea, dementia	Vitamin B3 deficiency
Isoniazid-associated neuropathy	Vitamin B6 deficiency
Megaloblastic anemia with neurologic signs	Vitamin B12 deficiency
Bleeding gums and poor wound healing	Vitamin C deficiency
Catecholamine precursor	Tyrosine
Serotonin precursor	Tryptophan
GABA precursor	Glutamate
Nitric oxide precursor	Arginine
Collagen hydroxylation	Vitamin C
Collagen cross-linking	Lysyl oxidase; copper
Osteogenesis imperfecta	Type I collagen
Cartilage collagen	Type II
Basement membrane collagen	Type IV
Von Gierke disease	Glucose-6-phosphatase system
Pompe disease	Lysosomal acid α-glucosidase
Cori disease	Debranching enzyme
Andersen disease	Branching enzyme
McArdle disease	Muscle glycogen phosphorylase
Rate-limiting enzyme of glycolysis	PFK-1
TCA enzyme also Complex II	Succinate dehydrogenase
Final electron acceptor in ETC	Oxygen
Tay–Sachs disease	Hexosaminidase A deficiency
Gaucher disease	β-Glucocerebrosidase deficiency
Niemann–Pick A/B	Acid sphingomyelinase deficiency
Highest triglyceride transport from intestine	Chylomicrons
Main atherogenic cholesterol carrier	LDL
ApoC-II	Activates LPL
ApoB-48	Chylomicrons
ApoB-100	VLDL, IDL and LDL; LDL-receptor binding
ApoA-I	Activates LCAT
HMG-CoA reductase	Rate-limiting cholesterol synthesis enzyme
Competitive inhibition	Km increases; Vmax unchanged
Pure noncompetitive inhibition	Vmax decreases; Km unchanged
Fat energy yield	9 kcal/g
Carbohydrate energy yield	4 kcal/g
Protein energy yield	4 kcal/g
Refeeding syndrome	Hypophosphatemia is a key clue

Vitamin Deficiencies

A

A — Eyes and epithelium

Night blindness, xerophthalmia, Bitot spots.

B1

Thiamine — Energy metabolism

Beriberi, Wernicke–Korsakoff; TPP-dependent enzymes.

B3

Niacin — Pellagra

Dermatitis, diarrhea, dementia.

B6

Pyridoxine — PLP

Neuropathy, seizures, sideroblastic anemia; isoniazid association.

B9

Folate — DNA synthesis

Megaloblastic anemia, increased homocysteine, normal methylmalonic acid.

B12

Cobalamin — Blood and nerves

Megaloblastic anemia, neurologic dysfunction, increased homocysteine and methylmalonic acid.

C

Ascorbic acid — Collagen

Scurvy, bleeding gums, perifollicular hemorrhage, poor healing.

Classic Contrasts

Contrast	Key distinction
Folate vs B12	Both cause megaloblastic anemia; B12 can cause neurologic dysfunction
Type I vs Type II collagen	Type I: bone/dentin; Type II: cartilage
Von Gierke vs McArdle	Severe fasting hypoglycemia vs exercise-induced muscle symptoms
Pompe vs other classic GSDs	Lysosomal glycogen accumulation with cardiomyopathy
Tay–Sachs vs Niemann–Pick	Hepatosplenomegaly is typically absent in Tay–Sachs but common in Niemann–Pick
Glycolysis vs TCA	Cytoplasm vs mitochondrial matrix
PFK-1 vs pyruvate kinase	PFK-1 is the major rate-limiting step; pyruvate kinase catalyzes the final ATP-generating step
Chylomicrons vs VLDL	Dietary triglycerides vs liver-derived triglycerides
LDL vs HDL	Cholesterol delivery to tissues vs reverse cholesterol transport
ApoC-II vs ApoE	LPL activation vs remnant uptake
Competitive vs noncompetitive inhibition	Increased Km vs reduced Vmax in pure noncompetitive inhibition

Energy metabolism

Pathway	Key yield
Glycolysis per glucose	Net 2 ATP + 2 NADH + 2 pyruvate
TCA per acetyl-CoA	3 NADH + 1 FADH₂ + 1 GTP + 2 CO₂
NADH	Approximately 2.5 ATP
FADH₂	Approximately 1.5 ATP
Complete glucose oxidation	Approximately 30–32 ATP