MCQ 91:
What type of bond forms between amino acids in a protein?
A) Ionic bond
B) Hydrogen bond
C) Peptide bond
D) Glycosidic bond
Answer: C) Peptide bond
Explanation: Peptide bonds are covalent bonds that link amino acids together to form proteins. Ionic bonds, hydrogen bonds, and glycosidic bonds serve different roles in molecular interactions.
MCQ 92:
Which of the following is a characteristic of chitin?
A) It is a component of plant cell walls.
B) It is a polysaccharide.
C) It is soluble in water.
D) It is a source of energy.
Answer: B) It is a polysaccharide.
Explanation: Chitin is a polysaccharide that serves as a structural component in the exoskeletons of arthropods and the cell walls of fungi. It is not found in plant cell walls and is not a soluble source of energy.
MCQ 93:
Which vitamin is known for its role in vision and skin health?
A) Vitamin A
B) Vitamin B12
C) Vitamin C
D) Vitamin D
Answer: A) Vitamin A
Explanation: Vitamin A is essential for vision, particularly in low-light conditions, and is important for skin health and immune function. The other vitamins have different roles.
MCQ 94:
Which of the following molecules serves as the primary energy currency of the cell?
A) ADP
B) AMP
C) ATP
D) NADH
Answer: C) ATP
Explanation: Adenosine triphosphate (ATP) is the primary energy currency of the cell, used to power various cellular processes. ADP (adenosine diphosphate) and AMP (adenosine monophosphate) are lower-energy forms, while NADH is a carrier of electrons in cellular respiration.
MCQ 95:
Which type of fatty acid is associated with heart health and is found in fish oil?
A) Saturated fatty acids
B) Monounsaturated fatty acids
C) Polyunsaturated fatty acids
D) Trans fatty acids
Answer: C) Polyunsaturated fatty acids
Explanation: Polyunsaturated fatty acids, particularly omega-3 fatty acids found in fish oil, are beneficial for heart health. Saturated fats are linked to heart disease, while trans fats are harmful.
MCQ 96:
Which type of bond is found in the secondary structure of proteins?
A) Peptide bonds
B) Ionic bonds
C) Hydrogen bonds
D) Disulfide bonds
Answer: C) Hydrogen bonds
Explanation: Hydrogen bonds stabilize the secondary structures of proteins, such as alpha-helices and beta-sheets. Peptide bonds link amino acids, while ionic and disulfide bonds contribute to tertiary structure.
MCQ 97:
What is the function of insulin in the body?
A) To increase blood glucose levels
B) To decrease blood glucose levels
C) To promote protein synthesis
D) To stimulate fat breakdown
Answer: B) To decrease blood glucose levels
Explanation: Insulin is a hormone produced by the pancreas that lowers blood glucose levels by promoting the uptake of glucose into cells and stimulating glycogen synthesis.
MCQ 98:
Which of the following describes an enzyme’s active site?
A) The region where substrate binds
B) The part of the enzyme that stabilizes the transition state
C) The location where allosteric regulation occurs
D) All of the above
Answer: D) All of the above
Explanation: The active site of an enzyme is where the substrate binds, and it plays a role in stabilizing the transition state. Allosteric regulation can also involve modifications at or near the active site.
MCQ 99:
What is the role of tRNA in protein synthesis?
A) To carry genetic information
B) To bring amino acids to the ribosome
C) To form part of the ribosomal structure
D) To catalyze peptide bond formation
Answer: B) To bring amino acids to the ribosome
Explanation: Transfer RNA (tRNA) transports specific amino acids to the ribosome, where they are added to the growing polypeptide chain during protein synthesis. mRNA carries genetic information, and rRNA forms part of the ribosome.
MCQ 100:
Which of the following is a function of nucleic acids?
A) Energy storage
B) Genetic information storage
C) Structural support
D) Catalysis
Answer: B) Genetic information storage
Explanation: Nucleic acids (DNA and RNA) are primarily responsible for storing and transmitting genetic information. They do not serve as energy storage, provide structural support, or act as catalysts (which is the role of proteins).
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