NEET MDS 2026: MERITERS PREDICTIONS | Biochemistry - 10 MOST LIKELY Question Topics

A targeted breakdown of the highest priority topics based on recent question patterns and examiner logic.

1. Enzymes & Enzyme Kinetics

High Priority

Core Focus

Competitive vs Non-competitive inhibition (Km and Vmax changes)
Michaelis-Menten constant (Km): Inversely proportional to enzyme affinity
Isoenzymes: LDH (Cardiac vs Hepatic), CPK (Muscle, Brain, Heart)

NEET MDS LOGIC

Pure graph-based logic. You must know that a Competitive inhibitor competes for the active site (Vmax stays the same, Km increases), whereas a Non-competitive inhibitor binds elsewhere (Vmax decreases, Km stays the same).

Framing: " In the presence of a competitive inhibitor, the Michaelis-Menten constant (Km) of an enzyme?"

Past Question Patterns

NEET MDS 2024: Effect of a competitive inhibitor on Vmax and Km
NEET MDS 2022: An enzyme with a low Km value indicates.
NEET MDS 2020: Isoenzyme of Lactate Dehydrogenase (LDH) elevated in myocardial infarction (LDH-1).
INI-CET 2021: Non-competitive inhibitors typically bind to.

2. Collagen Structure & Synthesis

Core Focus

Structure: Triple helix, Glycine is every 3rd amino acid (Gly-X-Y)
Hydroxylation step: Requires Vitamin C (Ascorbic acid) & Iron
Cross-linking step: Requires Lysyl oxidase and Copper

NEET MDS LOGIC

Collagen makes up dentin, cementum, and PDL, making it heavily tested in MDS. Know the exact amino acid sequence (Glycine is most abundant) and the specific mineral/vitamin cofactors for cross-linking.

Framing: "Which amino acid is the most abundant in collagen, occupying every third position in the polypeptide chain?"

Past Question Patterns

NEET MDS 2025: Most abundant amino acid in collagen.
NEET MDS 2022: Vitamin essential for the hydroxylation of proline and lysine residues in collagen.
NEET MDS 2020: Enzyme responsible for cross-linking of collagen fibrils, requiring copper as a cofactor.
AIIMS 2019: Defective collagen synthesis leading to hyperextensible skin and hypermobile joints is seen in.

3. Carbohydrate Metabolism

Core Focus

Glycolysis: Rate-limiting enzyme is Phosphofructokinase-1 (PFK-1)
TCA Cycle (Krebs Cycle): Rate-limiting enzyme is Isocitrate Dehydrogenase
ATP Yield: Aerobic glycolysis yields 32 (or 30) ATP per glucose molecule

NEET MDS LOGIC

ATP accounting and rate-limiting steps are standard fare. You must also know where these occur: Glycolysis occurs in the cytoplasm, TCA cycle in the mitochondria.

Framing: "The key regulatory, rate-limiting enzyme in the glycolytic pathway is?"

Past Question Patterns

NEET MDS 2023: Rate-limiting enzyme of glycolysis
NEET MDS 2021: Final end product of anaerobic glycolysis in skeletal muscle.
NEET MDS 2019: Subcellular location of the TCA cycle enzymes.
INI-CET 2020: Total net ATP yield from complete aerobic oxidation of one molecule of glucose.

4. Glycogen Storage Diseases

Core Focus

Type I (Von Gierke's): Glucose-6-phosphatase deficiency (Severe fasting hypoglycemia)
Type II (Pompe's): Lysosomal acid maltase deficiency (Cardiomegaly, early death)
Type V (McArdle's): Muscle phosphorylase deficiency (Muscle cramps during exercise)

NEET MDS LOGIC

Classic matching questions. Match the Roman numeral to the eponymous name, the deficient enzyme, and the primary clinical symptom (Liver = hypoglycemia, Muscle = cramps, Heart = Pompe's).

Framing: "A child presents with severe fasting hypoglycemia, hepatomegaly, and lactic acidosis. The deficient enzyme is most likely?"

Past Question Patterns

NEET MDS 2024: Deficient enzyme in Von Gierke's disease.
NEET MDS 2021: Glycogen storage disease characterized by severe cardiomegaly.
NEET MDS 2020: Enzyme deficient in McArdle's disease.
AIIMS 2018: Reason Von Gierke's disease presents with severe fasting hypoglycemia.

5. Lipid Metabolism & Lipoproteins

Core Focus

Beta-oxidation: Breakdown of fatty acids in mitochondria, requires Carnitine shuttle
Lipoproteins: LDL (transports cholesterol to tissues), HDL (reverse cholesterol transport)
Key Enzymes: LCAT (esterifies cholesterol in HDL), HMG-CoA Reductase (Cholesterol synthesis)

NEET MDS LOGIC

Transport mechanisms and clinical markers for cardiovascular risk. Know the function of 'Good' (HDL) vs 'Bad' (LDL) cholesterol, and that statins inhibit HMG-CoA Reductase.

Framing: "Which lipoprotein is primarily responsible for 'reverse cholesterol transport' from peripheral tissues back to the liver?"

Past Question Patterns

NEET MDS 2025: Lipoprotein responsible for reverse cholesterol transport.
NEET MDS 2022: Rate-limiting enzyme in cholesterol biosynthesis.
NEET MDS 2019: Shuttle system required for transporting long-chain fatty acids into mitochondria for beta-oxidation.
INI-CET 2021: Highest concentration of triglycerides is found in which lipoprotein?

6. Protein Metabolism & Transamination

Core Focus

Transamination: Transfer of amino group, requires Pyridoxal Phosphate (Vitamin B6)
Urea Cycle: Excretes toxic ammonia as urea; Rate-limiting enzyme is Carbamoyl Phosphate Synthetase I (CPS-I)
Location: Urea cycle occurs exclusively in the Liver (partly mitochondrial, partly cytosolic)

NEET MDS LOGIC

Nitrogen excretion is vital. Examiners frequently test the mandatory coenzyme for transaminases (AST/ALT), which is Vitamin B6.

Framing: "The coenzyme essential for all transamination reactions in amino acid metabolism is derived from?"

Past Question Patterns

NEET MDS 2024: Mandatory coenzyme for transamination reactions (Pyridoxal phosphate / Vitamin B6).
NEET MDS 2021: Rate-limiting enzyme of the Urea Cycle (Carbamoyl Phosphate Synthetase I).
NEET MDS 2020: Primary site of urea synthesis in the human body (Liver).
AIIMS 2019: Defect in the urea cycle primarily leads to the toxic accumulation of (Ammonia).

7. Fat-Soluble Vitamins (A, D, E, K)

Core Focus

Vitamin A: Retinol/Rhodopsin (Night blindness, Xerophthalmia)
Vitamin D: Calcitriol synthesis (Skin -> Liver -> Kidney), Rickets/Osteomalacia
Vitamin K: Gamma-carboxylation of clotting factors II, VII, IX, X

NEET MDS LOGIC

Direct clinical deficiency manifestations. Vitamin K is crucial for dental students because it directly impacts bleeding time and is the target of Warfarin therapy.

Framing: "Which vitamin serves as an essential coenzyme for the gamma-carboxylation of glutamic acid residues in prothrombin and other clotting factors?"

Past Question Patterns

NEET MDS 2023: Vitamin required for the hepatic synthesis of clotting factors II, VII, IX, and X.
NEET MDS 2022: Active form of Vitamin D synthesized in the kidney.
NEET MDS 2019: Earliest symptom of Vitamin A deficiency.
INI-CET 2020: Vitamin acting primarily as a biological antioxidant in cell membranes.

8. Water-Soluble Vitamins (B-Complex & C)

Core Focus

Vitamin C: Scurvy (bleeding gums), poor collagen hydroxylation
Vitamin B1 (Thiamine): Beriberi, Wernicke-Korsakoff syndrome (Alcoholics)
Vitamin B12 & Folate: Megaloblastic anemia; B12 deficiency causes neurological symptoms (Subacute combined degeneration)

NEET MDS LOGIC

Dental students must know Vitamin C due to scurvy/gingival bleeding, and B12/Folate due to glossitis and anemia. Remember: Only B12 deficiency causes neurological damage.

Framing: "A patient presents with swollen, bleeding gums and delayed wound healing. The deficient vitamin acts as a critical cofactor for?"

Past Question Patterns

NEET MDS 2025: Deficient vitamin causing scurvy acts as a cofactor for which enzyme?.
NEET MDS 2021: Pernicious anemia is caused by a deficiency of intrinsic factor, leading to malabsorption of.
NEET MDS 2020: Vitamin deficiency most commonly associated with chronic alcoholism leading to Wernicke's encephalopathy.
AIIMS 2018: Vitamin deficiency causing megaloblastic anemia WITHOUT neurological symptoms.

9. Molecular Biology (Central Dogma)

Core Focus

Replication: DNA Polymerase (Proofreading 3' to 5' exonuclease activity)
Transcription: RNA Polymerase, promoter regions (TATA box)
Post-Transcriptional Modifications: 5' Capping, 3' Poly-A tail, Intron splicing

NEET MDS LOGIC

Focus on the enzymes and what happens to mRNA before it leaves the nucleus. Exons are expressed, Introns are in the way (spliced out).

Framing: "The excision of introns and splicing of exons is a post-transcriptional modification that occurs in the?"

Past Question Patterns

NEET MDS 2024: Process of removing introns and joining exons is called.
NEET MDS 2022: Enzyme responsible for synthesizing mRNA in eukaryotes.
NEET MDS 2019: Function of the 3' to 5' exonuclease activity of DNA polymerase.
INI-CET 2021: The TATA box is a DNA sequence primarily involved in the initiation of.

10. Minerals (Calcium, Iron, Fluoride)

Core Focus

Calcium: Regulated by PTH (increases blood Ca), Calcitonin (decreases blood Ca)
Iron: Transported by Transferrin, stored as Ferritin/Hemosiderin
Fluoride: Inhibits Enolase in the bacterial glycolytic pathway (Anti-caries mechanism)

NEET MDS LOGIC

Fluoride's mechanism of action in bacteria (inhibiting enolase) is a highly tested dental crossover question. Know the specific storage vs transport proteins for Iron.

Framing: "Fluoride exerts its anti-caries effect primarily by inhibiting which enzyme in the bacterial glycolytic pathway?"

Past Question Patterns

NEET MDS 2025: Enzyme inhibited by fluoride during glycolysis
NEET MDS 2021: Primary storage form of iron in the body.
NEET MDS 2020: Hormone secreted by the thyroid gland that lowers serum calcium levels.
AIIMS 2019: The major transport protein for iron in blood plasma.

Topper Logic

Whenever you see a metabolic pathway, look for the "Bottleneck" (the rate-limiting enzyme) and the "Helper" (the Vitamin cofactor). Examiners rarely ask about intermediate steps; they ask about the start, the regulator, and the clinical outcome.