What term describes the orientation of the two DNA strands, which run in opposite directions?

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Multiple Choice

What term describes the orientation of the two DNA strands, which run in opposite directions?

Explanation:
The key idea is how the two DNA strands are oriented relative to each other. In a DNA double helix, the strands run in opposite directions: one goes from 5' to 3' and the other from 3' to 5'. This opposite arrangement is known as antiparallel. It matters because DNA polymerase, the enzyme that copies DNA, can only add nucleotides to the 3' end, so having antiparallel strands allows replication to proceed smoothly on both sides of the fork and enables correct base pairing. If the strands were parallel, or had no specific orientation, the mechanics of replication and the pattern of base pairing would not fit. Circular describes a shape rather than the directional arrangement of the two strands, so it doesn’t capture this feature.

The key idea is how the two DNA strands are oriented relative to each other. In a DNA double helix, the strands run in opposite directions: one goes from 5' to 3' and the other from 3' to 5'. This opposite arrangement is known as antiparallel. It matters because DNA polymerase, the enzyme that copies DNA, can only add nucleotides to the 3' end, so having antiparallel strands allows replication to proceed smoothly on both sides of the fork and enables correct base pairing. If the strands were parallel, or had no specific orientation, the mechanics of replication and the pattern of base pairing would not fit. Circular describes a shape rather than the directional arrangement of the two strands, so it doesn’t capture this feature.

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