Biochemistry-I MCQs | BIO202 MCQs | Set 2
Biochemistry-I MCQs | BIO202 MCQs| Set 2
MCQs (Multiple Choice Questions)
1) Which of the following amino acid is negatively charged at physiological pH?
a) Aspartate
b) Lysine
c) Alanine
d) Proline
Correct Answer:
The correct answer is 'a'.
Explanation:
Amino acids can be either positively charged, negatively charged, or neutral depending on their side chain properties and the pH of the environment. At physiological pH (around 7.4), the side chain (R group) of aspartate (abbreviated as Asp or D) is negatively charged. This is because the carboxyl group (COO-) in aspartate's side chain is deprotonated and carries a negative charge under these conditions. So, aspartate is negatively charged at physiological pH.
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2) Which of the following refers to particularly stable arrangements of amino acid residues giving rise to recurring structural patterns?
a) Primary structure
b) Secondary structure
c) Tertiary structure
d) Quaternary structure
Correct Answer:
The correct answer is 'b'.
Explanation:
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3) Keratin is present in _____________.
b) Nail
d) All of these
Correct Answer:
The correct answer is 'd'
Explanation:
Keratin is present in hair, nails, and hooves, among other structures in animals.
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4) Which of the following amino acid is involved in the hydrophobic interactions in the tertiary structure of protein?
a) Phenylalanine
b) Cysteine
c) Glycine
d) None of these
Correct Answer:
The correct answer is 'a'.
Explanation:
Phenylalanine is an amino acid that is often involved in hydrophobic interactions in the tertiary structure of proteins. Its nonpolar, hydrophobic side chain contributes to the stabilization of the protein's three-dimensional structure in a hydrophobic environment.
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5) The free energy of a protein molecule is influenced by __________.
a) Hydrophobicity
b) hydrogen bonds electrostatic
c) interactions
d) All of these
Correct Answer:
The correct answer is 'd'.
Explanation:
The free energy of a protein molecule is influenced by hydrophobicity, hydrogen bonds, electrostatic interactions, and various other factors. These interactions and properties play a significant role in determining the stability and folding of protein structures, and thus, they influence the protein's free energy.
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6) Which of the following diseases is caused by protein misfolding?
a) Alzheimer's disease
b) Huntington's disease
c) Parkinson's disease
d) All of these
Correct Answer:
The correct answer is 'd'.
Explanation:
All the diseases mentioned (Alzheimer's disease, Huntington's disease, and Parkinson's disease) are associated with protein misfolding. Protein misfolding is a common feature in many neurodegenerative diseases and can lead to the formation of toxic protein aggregates that contribute to the disease pathology.
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7) Iron is a __________.
a) non-metal
b) metalloid
c) transition metal
d) halogen
Correct Answer:
The correct answer is 'c'.
Explanation:
Iron is classified as a transition metal. Transition metals are elements found in the d-block of the periodic table, and they typically exhibit a variety of oxidation states and have properties distinct from both non-metals and alkali/alkaline earth metals. Iron is known for its important roles in various biological processes and industrial applications.
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8) Myoglobin can bind _____________ molecules of oxygen.
a) One
b) Two
c) Three
d) Four
Correct Answer:
The correct answer is 'a'.
Explanation:
Myoglobin can bind one molecule of oxygen. It is a protein found in muscle cells and is responsible for oxygen storage in muscle tissues.
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9) The partial pressure of oxygen (pO2) in lungs is about ______.
a) 30 mmHg
b) 50 mmHg
c) 100 mmHg
d) 200 mmHg
Correct Answer:
The correct answer is 'c'.
Explanation:
The partial pressure of oxygen (pO2) in the lungs is approximately 100 mmHg. This high oxygen partial pressure is essential for the efficient oxygenation of blood in the pulmonary capillaries during the process of respiration.
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10) In sickle cell anemia, Glutamate is replaced with __________.
a) Arginine
b) Alanine
c) Methionine
d) Valine
Correct Answer:
The correct answer is 'd'.
Explanation:
In sickle cell anemia, glutamate is replaced with valine in the hemoglobin molecule, resulting in the formation of abnormal hemoglobin known as hemoglobin S (HbS). This substitution of amino acids is a key factor in the molecular basis of the disease.
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