Proteins MCQs December 27, 2025August 2, 2024 by u930973931_answers 50 min Score: 0 Attempted: 0/50 Subscribe 1. What is the basic building block of proteins? (A) Nucleotides (B) Monosaccharides (C) Fatty acids (D) Amino acids 2. Which type of bond is primarily responsible for the secondary structure of proteins? (A) Peptide bonds (B) Ionic bonds (C) Hydrogen bonds (D) Disulfide bonds 3. What is the primary structure of a protein? (A) The folding into alpha helices and beta sheets (B) The sequence of amino acids (C) The three-dimensional shape of the protein (D) The interaction of multiple protein subunits 4. Which of the following is an example of a globular protein? (A) Collagen (B) Keratin (C) Elastin (D) Hemoglobin 5. Which protein is a major component of connective tissues in the body? (A) Myoglobin (B) Collagen (C) Actin (D) Hemoglobin 6. What type of protein structure is characterized by an alpha helix or beta-pleated sheet? (A) Primary (B) Quaternary (C) Tertiary (D) Secondary 7. Which enzyme is responsible for the digestion of proteins in the stomach? (A) Pepsin (B) Lipase (C) Amylase (D) Lactase 8. Which type of bond is involved in the tertiary structure of proteins? (A) Peptide bonds (B) Hydrogen bonds (C) Disulfide bonds (D) Ionic bonds 9. What is the role of chaperone proteins? (A) To degrade misfolded proteins (B) To catalyze biochemical reactions (C) To transport proteins to their cellular locations (D) To assist in the proper folding of proteins 10. Which amino acid contains a sulfur atom and forms disulfide bonds? (A) Glycine (B) Alanine (C) Cysteine (D) Serine 11. What is the function of enzymes in biological systems? (A) To increase the activation energy of reactions (B) To act as structural components (C) To catalyze biochemical reactions (D) To provide energy storage 12. Which protein is found in muscle cells and is responsible for muscle contraction? (A) Collagen (B) Myoglobin (C) Hemoglobin (D) Actin 13. Which of the following proteins is involved in oxygen transport in muscles? (A) Hemoglobin (B) Elastin (C) Collagen (D) Myoglobin 14. Which term describes the loss of a protein’s three-dimensional structure due to external factors? (A) Coagulation (B) Hydrolysis (C) Degradation (D) Denaturation 15. Which protein is known for its role in the immune response? (A) Insulin (B) Albumin (C) Antibody (D) Keratin 16. Which structural level of proteins involves multiple polypeptide chains interacting with each other? (A) Primary (B) Quaternary (C) Tertiary (D) Secondary 17. What type of bond links amino acids together in a protein chain? (A) Hydrogen bonds (B) Disulfide bonds (C) Peptide bonds (D) Ionic bonds 18. Which type of protein functions as a transport molecule in the blood? (A) Enzyme (B) Transport protein (C) Structural protein (D) Regulatory protein 19. Which of the following proteins is a major component of hair and nails? (A) Collagen (B) Myosin (C) Elastin (D) Keratin 20. Which protein is involved in the clotting process of blood? (A) Hemoglobin (B) Albumin (C) Fibrinogen (D) Insulin 21. What is the function of structural proteins in cells? (A) To act as catalysts for biochemical reactions (B) To regulate gene expression (C) To transport molecules across cell membranes (D) To provide support and shape to cells and tissues 22. Which amino acid is essential and must be obtained through the diet? (A) Glycine (B) Alanine (C) Serine (D) Valine 23. Which protein is responsible for storing and releasing iron in the body? (A) Hemoglobin (B) Albumin (C) Ferritin (D) Myoglobin 24. Which class of proteins is involved in cell signaling and communication? (A) Receptor proteins (B) Transport proteins (C) Enzymes (D) Structural proteins 25. Which protein is involved in the regulation of blood glucose levels? (A) Insulin (B) Hemoglobin (C) Collagen (D) Elastin 26. Which amino acid is known for its role in neurotransmitter synthesis? (A) Phenylalanine (B) Tryptophan (C) Cysteine (D) Arginine 27. What is the role of antibodies in the immune system? (A) To destroy pathogens directly (B) To enhance the activity of enzymes (C) To recognize and neutralize foreign invaders (D) To transport nutrients across cell membranes 28. Which protein plays a key role in muscle contraction along with actin? (A) Myoglobin (B) Troponin (C) Collagen (D) Myosin 29. Which protein is primarily involved in the storage of oxygen in muscle tissues? (A) Hemoglobin (B) Myoglobin (C) Ferritin (D) Albumin 30. What is the role of enzymes in metabolic pathways? (A) To provide structural support (B) To catalyze biochemical reactions (C) To act as energy carriers (D) To transport molecules across membranes 31. Which protein is known for its role in maintaining osmotic balance in the blood? (A) Insulin (B) Collagen (C) Ferritin (D) Albumin 32. Which protein structure level is determined by the unique sequence of amino acids? (A) Quaternary (B) Secondary (C) Tertiary (D) Primary 33. What term describes proteins that are embedded in the lipid bilayer of cell membranes and facilitate transport? (A) Structural proteins (B) Transport proteins (C) Receptor proteins (D) Enzymes 34. Which protein is crucial for the formation of the extracellular matrix in tissues? (A) Elastin (B) Hemoglobin (C) Collagen (D) Myoglobin 35. Which of the following proteins is involved in the process of muscle contraction by interacting with actin filaments? (A) Troponin (B) Myoglobin (C) Myosin (D) Collagen 36. Which enzyme is involved in the digestion of proteins in the small intestine? (A) Trypsin (B) Pepsin (C) Amylase (D) Lipase 37. Which term refers to the complex folding of a single polypeptide chain into a three-dimensional structure? (A) Primary structure (B) Tertiary structure (C) Secondary structure (D) Quaternary structure 38. Which of the following proteins is involved in the transport of oxygen in the blood? (A) Actin (B) Collagen (C) Hemoglobin (D) Myosin 39. Which type of protein structure involves multiple polypeptide chains interacting? (A) Primary (B) Quaternary (C) Tertiary (D) Secondary 40. Which of the following is a function of structural proteins? (A) Catalyzing biochemical reactions (B) Transporting molecules (C) Regulating gene expression (D) Providing support and structure to cells 41. Which protein type is responsible for the immune response by recognizing foreign molecules? (A) Antibodies (B) Transport proteins (C) Enzymes (D) Structural proteins 42. Which of the following amino acids is classified as essential? (A) Glutamine (B) Valine (C) Glycine (D) Serine 43. Which protein is involved in the formation of blood clots? (A) Fibrinogen (B) Hemoglobin (C) Insulin (D) Ferritin 44. Which type of protein is primarily responsible for regulating metabolic processes in the body? (A) Enzymes (B) Structural proteins (C) Transport proteins (D) Receptor proteins 45. What is the role of protein chaperones in cells? (A) To degrade misfolded proteins (B) To catalyze biochemical reactions (C) To transport proteins to their cellular locations (D) To assist in proper folding of proteins 46. Which protein is commonly used as a marker for muscle damage in medical tests? (A) Hemoglobin (B) Myoglobin (C) Collagen (D) Ferritin 47. Which amino acid is a precursor for the synthesis of serotonin and melatonin? (A) Phenylalanine (B) Tryptophan (C) Glutamine (D) Tyrosine 48. Which protein provides elasticity to tissues such as skin and blood vessels? (A) Collagen (B) Elastin (C) Keratin (D) Fibrinogen 49. Which term refers to the loss of protein structure due to high temperatures or changes in pH? (A) Aggregation (B) Hydrolysis (C) Denaturation (D) Condensation 50. Which type of protein is involved in the repair of damaged tissues and maintenance of cellular structures? (A) Enzymes (B) Regulatory proteins (C) Transport proteins (D) Structural proteins