Free Proteins and Amino Acids MCQs with Answers

• A. Myosin
• B. Albumin
• C. Globulin
• D. Prolamines

Explanation: Myosin is primarily a fibrous, contractile protein, although its heads contain globular regions.

• A. Proline
• B. Leucine
• C. Isoleucine
• D. Phenylalanine

Explanation: Leucine is purely ketogenic because its carbon skeleton forms acetyl-CoA or acetoacetate and cannot provide net glucose.

• A. Glutamate and glycine
• B. Alanine and glycine
• C. Glutamate and proline
• D. Proline and glycine

Explanation: Collagen has a characteristic repeating sequence rich in glycine and proline, including hydroxyproline.

• A. Pepsin
• B. Sucrase
• C. Chymotrypsin
• D. Amylase

Explanation: Pepsin begins protein digestion in the acidic stomach after activation from pepsinogen.

• A. Triacyl glycerol
• B. Proteins
• C. Glucose
• D. Lipids

Explanation: Proteins supply body nitrogen because amino acids contain amino groups, unlike carbohydrates and fats.

• A. Glycine
• B. Hydroxy proline
• C. Choline
• D. Glutamic acid

Explanation: Choline is a quaternary ammonium compound and a component of phospholipids, not an amino acid.

• A. Tyrosine
• B. Tryptophan
• C. Phenylalanine
• D. Methionine

Explanation: Tyrosine is converted by tyrosinase into DOPA and subsequently into melanin.

• A. Leucine
• B. Glycine
• C. Lycie
• D. Valine

Explanation: Glutathione is gamma-glutamyl-cysteinyl-glycine, so glycine forms its C-terminal, or reducing, end.

• A. Phenylalanine, Valine, Glycine
• B. Phenylalanine, Arginine Methinonine
• C. Phenylalanine, Tryptophan lysine
• D. Histidine, Glutamine, Valine

Explanation: Phenylalanine, tryptophan, and lysine are all essential amino acids that must be obtained from the diet.

• A. Phenylalanine
• B. Threonine
• C. Tryptophan
• D. Proline

Explanation: Proline is a non-essential amino acid because the body can synthesise it.

• A. Arginine
• B. Phenylalanine
• C. Glycine
• D. Phenylalanine, Glycine

Explanation: Phenylalanine contains a benzyl side chain with an aromatic phenyl ring.

• A. Methionine
• B. Valine
• C. Tryptophan
• D. Histidine

Explanation: Tryptophan contains an indole ring, which is a fused benzene-pyrrole structure.

• A. Carbohydrate
• B. Fat
• C. Protein
• D. None of the above

Explanation: The biuret test detects peptide bonds, producing a violet complex with proteins in alkaline copper solution.

• A. Lactalbumin
• B. Peptones
• C. Prolamines
• D. Simple

Explanation: Albumins and globulins are simple proteins because hydrolysis yields only amino acids, without a non-protein prosthetic group.

• A. H2 bond
• B. Hydrophobic
• C. Ionic bond
• D. None of the above
• E. Disulphide bond

Explanation: Hydrogen bonds, hydrophobic interactions, ionic bonds and disulfide bonds can all contribute to tertiary protein structure.