MCQ Collection
MDCAT 2026 MCQs
Practice MDCAT 2026 questions with answers and explanations.
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Correct Answer: C. 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: 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.
Choose an option to check your answer.
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. Mitochondrial matrix
Explanation:
The Krebs cycle oxidizes acetyl-CoA.
It produces reduced electron carriers and carbon dioxide.
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Correct Answer: A. Mitochondrial matrix
Explanation:
The Krebs cycle oxidizes acetyl-CoA.
It produces reduced electron carriers and carbon dioxide.
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Correct Answer: B. To convert light energy into chemical energy
Explanation:
Photosynthesis builds carbohydrates from carbon dioxide and water.
Light energy is captured by pigments such as chlorophyll.
