Here’s a bank of 60 multiple-choice questions (MCQs) for Chapter 5: Biochemistry, designed to match the BISE, Gujranwala style. The questions are categorized into easy, moderate, and tough levels, with answers provided at the end.
### MCQs for Chapter 5: Biochemistry
#### Easy Questions (18)
1. What is the primary function of carbohydrates in the body?
- A) Energy source
- B) Hormone regulation
- C) Immune response
- D) Genetic information
2. Which of the following is a monosaccharide?
- A) Sucrose
- B) Glucose
- C) Lactose
- D) Starch
3. Which carbohydrate is known as table sugar?
- A) Glucose
- B) Fructose
- C) Sucrose
- D) Galactose
4. What type of protein is responsible for muscle contraction?
- A) Enzymes
- B) Structural proteins
- C) Contractile proteins
- D) Transport proteins
5. Which food source is high in protein?
- A) Rice
- B) Chicken
- C) Potatoes
- D) Apples
6. What is the main component of lipids?
- A) Amino acids
- B) Nucleotides
- C) Fatty acids
- D) Sugars
7. Which type of fatty acid contains no double bonds?
- A) Saturated fatty acid
- B) Unsaturated fatty acid
- C) Trans fatty acid
- D) Omega-3 fatty acid
8. What is the function of nucleic acids?
- A) Energy storage
- B) Genetic information storage
- C) Immune response
- D) Structural support
9. Which of the following is a water-soluble vitamin?
- A) Vitamin A
- B) Vitamin D
- C) Vitamin C
- D) Vitamin E
10. Which vitamin is essential for the synthesis of collagen?
- A) Vitamin A
- B) Vitamin B12
- C) Vitamin C
- D) Vitamin K
11. What is the primary source of dietary lipids?
- A) Fruits
- B) Vegetables
- C) Oils and fats
- D) Grains
12. Which vitamin is known as the "sunshine vitamin"?
- A) Vitamin C
- B) Vitamin D
- C) Vitamin E
- D) Vitamin K
13. Which macromolecule provides the most energy per gram?
- A) Carbohydrates
- B) Proteins
- C) Lipids
- D) Nucleic acids
14. What type of bond links amino acids together in proteins?
- A) Hydrogen bond
- B) Ionic bond
- C) Peptide bond
- D) Covalent bond
15. What is the building block of proteins?
- A) Fatty acids
- B) Monosaccharides
- C) Amino acids
- D) Nucleotides
16. Which of the following is a function of lipids?
- A) Energy storage
- B) Providing structure
- C) Insulation
- D) All of the above
17. Which type of RNA is involved in protein synthesis?
- A) mRNA
- B) tRNA
- C) rRNA
- D) All of the above
18. What is the role of enzymes in biochemical reactions?
- A) Speed up reactions
- B) Slow down reactions
- C) Change the direction of reactions
- D) Consume energy
#### Moderate Questions (24)
19. Which polysaccharide is primarily found in plant cell walls?
- A) Starch
- B) Glycogen
- C) Cellulose
- D) Chitin
20. What process converts glucose into energy in cells?
- A) Photosynthesis
- B) Glycolysis
- C) Fermentation
- D) Respiration
21. Which type of lipid is most abundant in cell membranes?
- A) Triglycerides
- B) Phospholipids
- C) Steroids
- D) Waxes
22. What is the major source of energy for human cells?
- A) Proteins
- B) Carbohydrates
- C) Nucleic acids
- D) Lipids
23. Which vitamin is necessary for blood clotting?
- A) Vitamin B12
- B) Vitamin K
- C) Vitamin A
- D) Vitamin C
24. Which of the following is a characteristic of saturated fats?
- A) Liquid at room temperature
- B) Contains double bonds
- C) Solid at room temperature
- D) Contains more oxygen
25. Which amino acid is essential and must be obtained from the diet?
- A) Glycine
- B) Glutamine
- C) Valine
- D) Alanine
26. How many essential amino acids are there?
- A) 8
- B) 10
- C) 12
- D) 20
27. What is the primary structural component of DNA?
- A) Ribose sugar
- B) Deoxyribose sugar
- C) Phosphate group
- D) Nitrogenous base
28. What vitamin is important for maintaining healthy vision?
- A) Vitamin A
- B) Vitamin B2
- C) Vitamin C
- D) Vitamin D
29. Which of the following is a function of carbohydrates?
- A) Hormone production
- B) Providing energy
- C) Supporting immune function
- D) DNA synthesis
30. The process of converting starch into glucose is called:
- A) Hydrolysis
- B) Glycogenesis
- C) Glycogenolysis
- D) Lipolysis
31. What is the name of the bond formed between two monosaccharides?
- A) Glycosidic bond
- B) Peptide bond
- C) Hydrogen bond
- D) Ionic bond
32. Which type of vitamin can be stored in the body?
- A) Water-soluble vitamins
- B) Fat-soluble vitamins
- C) Both types
- D) Neither type
33. What role do antioxidants play in the body?
- A) Provide energy
- B) Protect against oxidative stress
- C) Help in digestion
- D) Promote growth
34. What type of lipid is cholesterol classified as?
- A) Triglyceride
- B) Phospholipid
- C) Steroid
- D) Glycerol
35. Which component of the cell membrane is critical for fluidity?
- A) Proteins
- B) Phospholipids
- C) Carbohydrates
- D) Nucleic acids
36. Which vitamin is involved in the metabolism of amino acids?
- A) Vitamin C
- B) Vitamin B6
- C) Vitamin D
- D) Vitamin E
37. What is the function of ribosomes in cells?
- A) Energy production
- B) Protein synthesis
- C) DNA replication
- D) Lipid synthesis
38. Which type of nucleic acid carries the genetic code from DNA to the ribosome?
- A) tRNA
- B) rRNA
- C) mRNA
- D) All of the above
#### Tough Questions (18)
39. What is the primary reason for the different properties of fatty acids?
- A) Length of the carbon chain
- B) Number of double bonds
- C) Type of functional groups
- D) Presence of hydroxyl groups
40. How do enzymes lower the activation energy of reactions?
- A) By providing energy
- B) By increasing temperature
- C) By stabilizing the transition state
- D) By changing the pH
41. Which metabolic pathway occurs in the mitochondria?
- A) Glycolysis
- B) Krebs cycle
- C) Fermentation
- D) Glycogenesis
42. How does the structure of DNA contribute to its function?
- A) Double helix structure allows for replication
- B) Single strand prevents mutations
- C) Circular form increases stability
- D) Linear form allows for easier access
43. What is the function of myoglobin?
- A) Transport oxygen in the blood
- B) Store oxygen in muscle tissues
- C) Produce energy
- D) Regulate blood pressure
44. Which process converts glucose into pyruvate?
- A) Krebs cycle
- B) Glycolysis
- C) Fermentation
- D) Citric acid cycle
45. What role does folate (Vitamin B9) play in the body?
- A) Aids in vision
- B) Involved in DNA synthesis
- C) Supports immune function
- D) Regulates blood sugar
46. Which nucleic acid is involved in the synthesis of proteins from amino acids?
- A) DNA
- B) mRNA
- C) tRNA
- D) Both B and C
47. How are proteins denatured?
- A) By changing the temperature or pH
- B) By adding more amino acids
- C) By increasing pressure
- D) By removing water
48. Which vitamin is required for the absorption of calcium?
- A) Vitamin C
- B) Vitamin D
- C) Vitamin E
- D) Vitamin K
49. Which of the following statements about unsaturated fatty acids is true?
- A) They have a higher melting point than saturated fats
- B) They contain one or more double bonds
- C) They are solid at room temperature
- D) They are found only in animal fats
50. What is the significance of the sequence of nitrogenous bases in DNA?
- A) It determines the type of protein synthesized
- B) It stabilizes the DNA structure
- C) It helps in DNA replication
- D) It prevents mutations
51. Which vitamin deficiency can lead to scurvy?
- A) Vitamin A
- B) Vitamin C
- C) Vitamin K
- D) Vitamin B12
52. How many hydrogen atoms are typically found in saturated fatty acids?
- A) Fewer than unsaturated fatty acids
- B) Equal to the number of carbon atoms
- C) Twice the number of carbon atoms
- D) None of the above
53. Which carbohydrate can be stored in the liver for energy?
- A) Fructose
- B) Sucrose
- C) Glycogen
- D) Cellulose
54. What type of interaction stabilizes the tertiary structure of proteins?
- A) Ionic bonds
- B) Hydrogen bonds
- C) Hydrophobic interactions
- D) All of the above
55. What is the main function of the pancreas in relation to digestion?
- A) Produces bile
- B) Produces digestive enzymes
- C) Absorbs nutrients
- D) Stores energy
56. Which enzyme is involved in the breakdown of starch into glucose?
- A) Amylase
- B) Lipase
- C) Protease
- D) Nuclease
57. What is the function of NAD+ in cellular respiration?
- A) To transport oxygen
- B) To store energy
- C) To act as an electron carrier
- D) To synthesize ATP
58. What is the role of phospholipids in biological membranes?
- A) Energy storage
- B) Provide rigidity
- C) Form a lipid bilayer
- D) Act as hormones
59. Which vitamin is associated with the prevention of neural tube defects?
- A) Vitamin B6
- B) Vitamin B12
- C) Folate (Vitamin B9)
- D) Vitamin D
60. What type of bond holds the nitrogenous bases together in the DNA double helix?
- A) Covalent bond
- B) Ionic bond
- C) Hydrogen bond
- D) Disulfide bond
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### Answers
1. A
2. B
3. C
4. C
5. B
6. C
7. A
8. B
9. C
10. C
11. C
12. B
13. C
14. C
15. C
16. D
17. D
18. A
19. C
20. B
21. B
22. B
23. B
24. A
25. C
26. A
27. B
28. A
29. B
30. A
31. A
32. B
33. B
34. C
35. B
36. B
37. B
38. C
39. B
40. C
41. B
42. A
43. B
44. B
45. B
46. D
47. A
48. B
49. B
50. A
51. B
52. C
53. C
54. D
55. B
56. A
57. C
58. C
59. C
60. C