MCQ on Protein Metabolism with Answers
Q1. Which of the following statements is true about proteins?
A) Proteins are made up of amino acids.
B) Proteins are essential for the development of skin, teeth, and bones.
C) Protein is the only nutrient that can build, repair and maintain body tissues.
D) All of the above
Correct Answer: D
Explanation: Proteins serve multiple vital functions, including growth, repair, and structural support—making all options correct.
Q2. After normal adults eat too much high-protein food, the following metabolic activity is generally not significantly enhanced:
A) Synthesize tissue proteins
B) Deamination
C) Synthesis of carbohydrates and fats
D) Amino group converted to urea
Correct Answer: A
Explanation: Once the protein need is met, excess protein is not used to build tissues; instead, it’s broken down.
Q3. Which of the following statements is true about proteins?
A) Proteins are polymers of glucose
B) Proteins are polymers of amino acids
C) Proteins are polymers of peptide bonds
D) Proteins are polymers of disulfide bridges
Correct Answer: B
Explanation: Proteins are linear chains (polymers) of amino acids linked by peptide bonds.
Q4. Transamination reaction in amino acid synthesis is catalyzed by enzyme:
A) Nitric oxide synthase
B) Decarboxylase
C) Aminotransferase
D) Glutamate decarboxylase
Correct Answer: C
Explanation: Aminotransferases catalyze the transfer of amino groups between amino acids and keto acids.
Q5. Which of the following statements about protein metabolism is false?
A) Bacteriophages use bacterial enzymes to synthesize their own proteins
B) Green plants can synthesize their own proteins
C) tRNA, mRNA, and rRNA are all involved in protein synthesis
D) Pneumococcus uses ribosomes in human cells to synthesize its own proteins
Correct Answer: D
Explanation: Pneumococcus uses its own ribosomes, not human ones; this statement is incorrect.
Q6. Which of the following is not the function of proteins?
A) Helps in digesting food
B) Carries genetic information
C) Fights against the invading pathogens
D) Helps in transporting oxygen in the blood
Correct Answer: B
Explanation: Carrying genetic information is a function of nucleic acids, not proteins.
Q7. Which statement is correct about protein synthesis in animals?
A) The synthesis of all proteins requires energy
B) The synthesized proteins are transported out of the cell
C) Synthesized proteins cannot enter the nucleus
D) Synthesized proteins are used for the renewal of Glucose
Correct Answer: A
Explanation: Protein synthesis is an energy-intensive process requiring ATP and GTP.
Q8. Which of the following statements about the structure of proteins is true?
A) The sequence of amino acids in a protein represents the secondary structure
B) The helices of proteins are always left-handed
C) Adult human hemoglobin consists of two subunits
D) Proteins are heteropolymers containing strings of amino acids
Correct Answer: D
Explanation: Proteins are heteropolymers made up of 20 different amino acids in varying sequences.
Q9. The statement about protein metabolism that is incorrect is:
A) Lack of protein can lead to swelling and reduced immunity
B) Protein is essential for brain cell development
C) The final metabolites of proteins are all inorganic substances
D) Protein can also provide energy
Correct Answer: C
Explanation: Protein metabolism produces both organic (e.g., urea) and inorganic end products.
Q10. The statement about protein metabolism that is incorrect is:
A) Lack of protein can lead to reduced resistance and swelling
B) Protein deficiency affects brain development
C) All final metabolites are inorganic
D) Protein can provide energy
Correct Answer: C
Explanation: This is repeated; same reason—protein metabolism does not produce only inorganic metabolites.
Q11. The correct statement about human protein metabolism is:
A) Excessive protein burdens the liver/kidneys and may cause obesity
B) Just sufficient intake guarantees adequate protein synthesis
C) Nitrogen is never excreted during transamination
D) Adolescents excrete more nitrogen than intake
Correct Answer: A
Explanation: Too much protein stresses excretory organs and can contribute to weight gain if unused energy is stored as fat.
Q12. Based on their energy value and cell content, proteins, carbohydrates, and fats:
A) Fat is the main source of energy
B) Carbohydrates are the main source of energy
C) Protein is the main source of energy
D) All three provide energy and are energy substances
Correct Answer: D
Explanation: All macronutrients (proteins, carbohydrates, and fats) serve as energy sources when metabolized.
Q13. Which of the following is not true about secondary protein structure?
A) Hydrophilic/hydrophobic properties are important
B) Intramolecular hydrogen bonds play a key role
C) Alpha-helix and beta-sheet are examples
D) Secondary structure is unaffected by amino acid steric hindrance
Correct Answer: A
Explanation: Hydrophobic/hydrophilic interactions mostly affect tertiary structure, not secondary.