1. What is the role of myosin in muscle tissue?

A. Storage of oxygen B. Structural framework C. Contractile protein enabling contraction D. Transport protein

2. What distinguishes primary derived proteins from secondary derived proteins?

A. Primary are denatured or first hydrolyzed products; secondary are degraded products due to breakdown of peptide bonds B. Primary contain prosthetic groups; secondary do not C. Primary are conjugated proteins; secondary are simple proteins D. Primary are fibrous; secondary are globular

3. In collagen, what unique secondary structure contributes to its strength?

A. β-pleated sheets B. Triple helix C. α-helix D. Random coils

4. Which is true about amyloid proteins in Alzheimer's disease?

A. They contain α-helices predominantly B. They display β-pleated sheet structures C. They are rich in proline and hydroxyproline D. They are conjugated phosphoproteins

5. What defines nucleoproteins?

A. Simple proteins with carbohydrate prosthetic groups B. Basic proteins combined with nucleic acids as prosthetic groups C. Proteins combined with heme prosthetic groups D. Proteins combined with phosphoric acid

6. Which of the following is an example of a phosphoprotein?

A. Hemoglobin B. Vitellin C. Mucin D. Histone

7. The chemical reaction joining two amino acids into a dipeptide is called:

A. Hydration B. Hydrolysis C. Condensation D. Oxidation

8. What defines a simple protein in terms of its composition after hydrolysis?

A. It yields both amino acids and prosthetic groups B. It yields only amino acids or their derivatives C. It yields nucleic acids D. It yields carbohydrates and amino acids

9. Which of the following proteins is soluble in 70-80% alcohol?

A. Albumins B. Prolamins C. Globulins D. Glutelins

10. What type of interaction stabilizes the quaternary structure of proteins?

A. Covalent disulfide bonds B. Covalent peptide bonds C. Non-covalent interactions such as hydrogen bonding and hydrophobic interactions D. Ionic bonds only

11. What is the main reason understanding a protein’s primary structure is crucial in molecular study of diseases like sickle cell anemia?

A. It identifies the tertiary folding pattern responsible for function B. It establishes the presence of prosthetic groups C. It helps detect abnormal amino acid sequences caused by genetic mutation D. It provides information about protein solubility properties

12. What type of protein functions primarily as enzymes catalyzing biological reactions?

A. Storage proteins B. Contractile proteins C. Catalytic proteins D. Structural proteins

13. The β-turn or bend in protein secondary structure typically includes which feature?

A. It consists of eight residues B. It causes abrupt reversal in chain direction C. It is stabilized only by disulfide bonds D. It forms the antigen binding site

14. What type of secondary protein structure exhibits parallel or antiparallel arrangements stabilized by hydrogen bonding?

A. α-Helix B. β-pleated sheet C. Triple helix D. Loop regions

15. Which of these proteins is involved in oxygen transport in blood?

A. Albumin B. Hemoglobin C. Transferrin D. Myosin

16. What is the main characteristic of simple proteins upon hydrolysis?

A. They yield amino acids and prosthetic groups B. They yield only amino acid residues or their derivatives C. They yield carbohydrates and proteins D. They yield nucleic acids and proteins

17. What interaction is NOT typically involved in protein tertiary structure stabilization?

A. Hydrogen bonding B. Peptide bonding C. Hydrophobic interactions D. Van der Waals forces

18. What is the function of regulatory proteins like insulin and glucagon?

A. Transport oxygen B. Provide structural support C. Regulate cellular or physiological activity D. Act as antibodies

19. Casein in milk is an example of which type of conjugated protein?

A. Lipoprotein B. Phosphoprotein C. Chromoprotein D. Glycoprotein

20. Which type of bond primarily links amino acids together in a protein?

A. Hydrogen bond B. Peptide bond C. Disulfide bond D. Ionic bond

21. The α-Helix secondary structure of proteins is maintained by hydrogen bonding between which groups?

A. Side chain amine and carboxyl groups four residues apart B. Backbone carbonyl oxygen and amide hydrogen four residues apart C. Side chain hydroxyl and carboxyl groups in adjacent residues D. Backbone carbonyl oxygen and imino nitrogen in the same residue

22. Which structural protein provides tensile strength similar to steel in biological tissues?

A. Elastin B. Keratin C. Collagen D. Actin

23. Which amino acids are considered semi-essential in children but synthesized in adults?

A. Arginine and histidine B. Lysine and leucine C. Glycine and alanine D. Methionine and tryptophan

24. Which of these is a transport protein?

A. Apoferritin B. Transferrin C. Collagen D. Actin

25. Histones are classified as which type of protein?

A. Simple proteins B. Conjugated proteins C. Regulatory proteins D. Derived proteins

26. Which of the following best describes primary derived proteins?

A. Proteins formed by simple peptide chains only B. Proteins formed by more than one polypeptide subunit C. Denatured or first hydrolyzed products of proteins such as coagulated proteins D. Proteins with non-protein prosthetic groups attached

27. What defines a conjugated protein?

A. A protein containing only amino acids B. A protein combined with a non-protein prosthetic group C. A denatured protein D. A protein soluble in alcohol

28. Which of the following is true regarding hydrophobic amino acids?

A. They tend to be found on the exterior of protein in aqueous environments B. They have polar side chains C. They tend to cluster inside the protein core away from water D. They have acidic side chains

29. What is the significance of the primary structure of a protein?

A. It determines the protein’s solubility only B. It refers to amino acid sequence and disulfide bond location crucial for function C. It is the folded 3D active structure D. It includes quaternary interactions

30. Which of the following is a fibrous structural protein?

A. Hemoglobin B. Albumin C. Collagen D. Myosin

31. Which conjugated protein contains heme as a prosthetic group responsible for its colored appearance?

A. Casein B. Mucin C. Hemoglobin D. Nucleohistone

32. Which of these is NOT a type of protein classification based on physical and chemical properties?

A. Simple proteins B. Conjugated proteins C. Derived proteins D. Regulatory proteins

33. Which amino acid contains an imino group instead of an amino group?

A. Glycine B. Proline C. Lysine D. Histidine

34. The α-helix secondary structure is stabilized by hydrogen bonding between:

A. NH and CO groups of different polypeptide chains B. NH and CO groups approximately four residues apart in the same chain C. Side chains of amino acids D. Peptide bonds

35. Which amino acid classification is based on side chain polarity?

A. Essential and non-essential B. Acidic, basic, neutral C. Hydrophobic and hydrophilic D. Ketogenic and glycogenic

36. What characteristic distinguishes glycoproteins from proteoglycans (mucoproteins) in conjugated proteins?

A. Presence of metal ions as prosthetic groups B. Amount of carbohydrate content relative to protein C. Type of polypeptide chain folding D. Presence of nucleic acid as prosthetic group

37. Which of the following amino acids is unique because it contains an imino group instead of an amino group?

A. Lysine B. Proline C. Serine D. Glycine

38. Which statement regarding the tertiary structure of proteins is correct?

A. It is stabilized exclusively by peptide bonds B. It involves folding bringing distant amino acids close together forming active sites C. It only occurs in fibrous proteins D. It refers to the sequence of amino acids

39. What is the main functional consequence of a protein's quaternary structure?

A. Folding into a single polypeptide chain B. Formation of active or catalytic sites within a single chain C. Arrangement of multiple polypeptide subunits into a functional complex D. Linear sequence of amino acids forming peptide bonds

40. Glycoproteins differ from proteoglycans primarily in:

A. Protein composition B. Carbohydrate content C. Color of prosthetic group D. Presence of nucleic acids

41. What role does the lysinonorleucine bond play in protein structure?

A. Stabilizes alpha helical coils by hydrogen bonding B. Cross-links collagen triple helices to give tensile strength C. Links nucleic acids to proteins in nucleoproteins D. Forms ionic bonds between charged side chains

42. What is the role of immunoglobulins?

A. Transport oxygen B. Defend the body against pathogens C. Store amino acids D. Catalyze metabolic reactions

43. Which type of bond primarily stabilizes the tertiary structure of proteins by linking the sulfhydryl groups of cysteine residues?

A. Peptide bond B. Hydrogen bond C. Disulfide bond D. Electrostatic interaction

44. Which protein stores iron in the body?

A. Myoglobin B. Transferrin C. Apoferritin D. Hemoglobin

45. Which amino acid side chains contain a hydroxyl group?

A. Serine, threonine, tyrosine B. Lysine, histidine, arginine C. Leucine, isoleucine, valine D. Aspartic acid, glutamic acid

46. What happens to proteins when they denature?

A. They break peptide bonds completely B. They lose tertiary and secondary structures without breaking primary sequence C. They become conjugated proteins D. They form prosthetic groups

47. Which amino acids are considered ketogenic?

A. Leucine and lysine B. Glycine and alanine C. Phenylalanine and tyrosine D. Isoleucine and valine

48. Which of the following is a chromoprotein?

A. Myosin B. Catalase C. Casein D. Albumin

49. Which bond is NOT a covalent bond in protein structure?

A. Peptide bond B. Disulfide bond C. Hydrogen bond D. Lysinonorleucine bond

50. Which type of amino acids are considered semi-essential for humans because they are not synthesized by growing children?

A. Lysine and leucine B. Arginine and histidine C. Methionine and valine D. Phenylalanine and tryptophan