Biomolecules — NEET UG practice

1. To solve this, we need to recall the general structure of amino acids and how individual amino acids are classified.

2. Statement A says amino acids are substituted methanes. Since every amino acid has a central carbon (like methane's carbon) attached to an amino group, a carboxyl group, a hydrogen, and a variable R group, this description is correct.

3. Statement B claims serine is an aromatic amino acid, but serine actually carries a hydroxyl (-OH) group on its R group, which makes it an alcoholic amino acid, not an aromatic one, so this statement is incorrect.

4. Statement C says valine is a neutral amino acid. Since valine's R group is a simple non-polar hydrocarbon branch with no acidic or basic character, it is correctly classified as neutral, so this statement is correct.

5. Statement D claims lysine is acidic, but lysine has an extra amino group in its side chain, giving it basic character, so lysine is actually a basic amino acid, making this statement incorrect.

6. Since only statements A and C are correct, the answer matches option C.

Hence, the answer is C.

1. To match each item correctly, we need to recall what biological category each molecule belongs to.

2. Trypsin is a digestive protein that breaks down other proteins by catalysing peptide bond hydrolysis. Therefore Trypsin → Enzyme (III)

3. Morphine is a naturally occurring secondary metabolite derived from plants, and such nitrogen-containing plant compounds are classified as alkaloids. Hence Morphine → Alkaloid (IV)

4. Concanavalin A is a well-known carbohydrate-binding protein, a category called lectins. So Concanavalin A → Lectin (II)

5. Collagen is a structural protein that fills the space between cells and provides support, functioning as the intercellular ground substance. Therefore Collagen → Intercellular ground substance (I)

6. Combining all matches gives A-III, B-IV, C-II, D-I, which corresponds to option A.

Hence, the answer is A.

1. Enzymes are classified into six major classes based on the type of reaction they catalyse, so we need to compare the reaction shown with each class's defining feature.

2. Transferases catalyse the transfer of a functional group from one substrate to another, which does not match a reaction that simply removes a group and forms a double bond.

3. Isomerases catalyse the rearrangement of atoms within a single molecule to form a positional, optical, or geometric isomer, which is also different from group removal.

4. Lyases catalyse the removal of a group from a substrate through a mechanism other than hydrolysis, and this removal typically leaves behind a double bond in the product. Since the given reaction shows exactly this pattern Therefore Enzyme class E → Lyases

5. Ligases catalyse the joining together of two separate molecules, usually using energy from ATP, which does not fit a reaction where a group is being removed.

6. Since the reaction depicts removal of a group with formation of a double bond (not hydrolysis, isomerisation, transfer, or joining), the enzyme class must be Lyases, matching option C.

Hence, the answer is C.