MCQ Collection
MDCAT Biology MCQs
Practice MDCAT Biology questions with answers and explanations.
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Correct Answer: D. Adenine and guanine
Explanation:
Purines have a double-ring structure.
Adenine and guanine occur in both DNA and RNA.
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Correct Answer: D. The two strands run in opposite 5′ to 3′ directions
Explanation:
One strand runs 5′ to 3′ and the other 3′ to 5′.
This orientation is important for replication enzymes.
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Correct Answer: A. Adenine and guanine
Explanation:
Purines have a double-ring structure.
Adenine and guanine occur in both DNA and RNA.
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Correct Answer: A. Production of an identical DNA copy
Explanation:
DNA replication occurs before cell division.
Each daughter DNA molecule contains one old and one new strand.
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Correct Answer: B. Cytosine and thymine
Explanation:
DNA pyrimidines have single-ring structures.
They are cytosine and thymine.
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Correct Answer: B. Production of an identical DNA copy
Explanation:
DNA replication occurs before cell division.
Each daughter DNA molecule contains one old and one new strand.
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Correct Answer: C. Cytosine and thymine
Explanation:
DNA pyrimidines have single-ring structures.
They are cytosine and thymine.
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Correct Answer: C. Production of an identical DNA copy
Explanation:
DNA replication occurs before cell division.
Each daughter DNA molecule contains one old and one new strand.
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Correct Answer: D. Cytosine and thymine
Explanation:
DNA pyrimidines have single-ring structures.
They are cytosine and thymine.
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Correct Answer: D. Each new molecule contains one parental and one newly synthesized strand
Explanation:
The parental strands separate and serve as templates.
Each completed double helix preserves one original strand.
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Correct Answer: A. A pairs with T, and G pairs with C
Explanation:
Hydrogen bonding produces specific pairing.
This complementarity supports accurate replication.
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Correct Answer: A. Each new molecule contains one parental and one newly synthesized strand
Explanation:
The parental strands separate and serve as templates.
Each completed double helix preserves one original strand.
