Question

exam lesson name: genetics and inheritance
exam number: 700943rr
exam guidelines
exam instructions
question 8 of 20 :
select the best answer for the question.

1. the dna double helix is antiparallel. this means that the two strands

a. are parallel and are the mirror images of each other.
b. cross over each other many times.
c. are parallel and are identical to each other.
d. are parallel and run in opposite directions.
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Explanation:

To solve this, we recall the definition of the DNA double helix being antiparallel. Antiparallel in DNA means the two strands are parallel but run in opposite directions (one strand has a 5’ to 3’ direction and the other 3’ to 5’).

• Option A: Mirror images is not the definition of antiparallel.
• Option B: Crossing over is about genetic recombination, not antiparallel structure.
• Option C: The strands are complementary, not identical.
• Option D: Matches the definition of antiparallel (parallel and opposite directions).

Answer:

D. are parallel and run in opposite directions.