BIO Chemistry most important questions

Biochemistry MCQ Quiz – Questions 1 to 5

1. Which vitamin is essential for blood clotting?

✅ Correct Answer: Vitamin K
💡 Explanation: Vitamin K helps in synthesis of clotting factors in blood.

2. The building blocks of proteins are:

✅ Correct Answer: Amino acids
💡 Explanation: Proteins are made up of amino acid chains joined by peptide bonds.

3. Which enzyme breaks down starch into maltose?

✅ Correct Answer: Amylase
💡 Explanation: Amylase converts starch (a polysaccharide) into maltose (a disaccharide).

4. DNA is composed of repeating units called:

✅ Correct Answer: Nucleotides
💡 Explanation: DNA is a polymer of nucleotides, each consisting of a sugar, phosphate, and nitrogenous base.

5. Which of the following is a disaccharide?

✅ Correct Answer: Lactose
💡 Explanation: Lactose is a disaccharide made of glucose and galactose.

6. Which of the following is the energy currency of the cell?

✅ Correct Answer: ATP
💡 Explanation: ATP (Adenosine Triphosphate) stores and transfers energy within cells.

7. Which lipid is the major component of cell membranes?

✅ Correct Answer: Phospholipids
💡 Explanation: Phospholipids form bilayers that are the foundation of all cell membranes.

8. Enzymes are chemically:

✅ Correct Answer: Proteins
💡 Explanation: Most enzymes are globular proteins that catalyze biochemical reactions.

9. Which of the following is a reducing sugar?

✅ Correct Answer: Glucose
💡 Explanation: Glucose contains a free aldehyde group, allowing it to act as a reducing agent.

10. Which of the following biomolecules does not form polymers?

✅ Correct Answer: Lipids
💡 Explanation: Unlike proteins or nucleic acids, lipids are not made of repeating monomer units.