MCQ 51:
Which amino acid is known for having a side chain that can form disulfide bonds?
A) Cysteine
B) Methionine
C) Tryptophan
D) Serine
Answer: A) Cysteine
Explanation: Cysteine contains a thiol (-SH) group in its side chain, allowing it to form disulfide bonds with other cysteine residues, which are important for stabilizing protein structure.
MCQ 52:
Which of the following describes the role of chaperone proteins?
A) They catalyze reactions.
B) They help in DNA replication.
C) They assist in protein folding.
D) They transport molecules across membranes.
Answer: C) They assist in protein folding.
Explanation: Chaperone proteins assist in the proper folding of other proteins, ensuring they achieve their functional three-dimensional structures. They do not catalyze reactions, replicate DNA, or transport molecules.
MCQ 53:
Which of the following is a non-reducing sugar?
A) Glucose
B) Fructose
C) Sucrose
D) Maltose
Answer: C) Sucrose
Explanation: Sucrose is a non-reducing sugar because it does not have a free aldehyde or ketone group that can reduce other compounds. Glucose, fructose, and maltose can act as reducing sugars.
MCQ 54:
Which type of fatty acid is characterized by having multiple double bonds?
A) Saturated fatty acid
B) Monounsaturated fatty acid
C) Polyunsaturated fatty acid
D) Trans fatty acid
Answer: C) Polyunsaturated fatty acid
Explanation: Polyunsaturated fatty acids contain multiple double bonds in their carbon chain, while saturated fatty acids have no double bonds, and monounsaturated fatty acids have one double bond.
MCQ 55:
Which of the following molecules is a primary component of the plasma membrane?
A) Phospholipids
B) Steroids
C) Proteins
D) Glycogen
Answer: A) Phospholipids
Explanation: Phospholipids form the fundamental structure of the plasma membrane, creating a bilayer. Proteins and steroids are also present but are not the primary structural components.
MCQ 56:
Which of the following vitamins is involved in collagen synthesis?
A) Vitamin A
B) Vitamin C
C) Vitamin D
D) Vitamin K
Answer: B) Vitamin C
Explanation: Vitamin C is crucial for collagen synthesis, as it acts as a cofactor for the enzymes involved in collagen production. Other vitamins have different roles in the body.
MCQ 57:
Which of the following processes occurs in the cytoplasm of eukaryotic cells?
A) Krebs cycle
B) Oxidative phosphorylation
C) Glycolysis
D) Electron transport chain
Answer: C) Glycolysis
Explanation: Glycolysis occurs in the cytoplasm of eukaryotic cells, breaking down glucose into pyruvate. The Krebs cycle and oxidative phosphorylation occur in the mitochondria, and the electron transport chain is also mitochondrial.
MCQ 58:
Which of the following amino acids can be classified as polar?
A) Alanine
B) Valine
C) Asparagine
D) Phenylalanine
Answer: C) Asparagine
Explanation: Asparagine is a polar amino acid due to its side chain containing an amide group, which can form hydrogen bonds. Alanine and valine are nonpolar, and phenylalanine is aromatic.
MCQ 59:
What is the primary role of the ribosome in the cell?
A) Lipid synthesis
B) Protein synthesis
C) Energy production
D) DNA replication
Answer: B) Protein synthesis
Explanation: Ribosomes are the cellular structures responsible for synthesizing proteins by translating mRNA into amino acid sequences. They do not perform lipid synthesis, energy production, or DNA replication.
MCQ 60:
Which of the following is a function of lipids?
A) Energy storage
B) Insulation
C) Cell membrane formation
D) All of the above
Answer: D) All of the above
Explanation: Lipids serve multiple functions, including energy storage, insulation, and forming cell membranes. They are diverse biomolecules with various roles in biological systems.
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