True or False: Double-stranded DNA consists of two antiparallel strands, with one running 5' to 3' and the other 3' to 5'.

True or False: Double-stranded DNA consists of two antiparallel strands, with one running 5' to 3' and the other 3' to 5'.

• A. True
• B. False
• C. Not specified
• D. Both

Answer: (A)

In double-stranded DNA, the two strands run in opposite directions, with the sugar-phosphate backbones facing outward. One strand is oriented 5' to 3' while the other runs 3' to 5'. This antiparallel arrangement is essential for proper base pairing—adenine pairs with thymine and cytosine pairs with guanine—so the helix can stabilize with uniform geometry. It also aligns with how DNA is replicated and transcribed, since polymerases add nucleotides to the 3' end and read templates in the 3' to 5' direction on the opposite strand. So the statement is true.

In double-stranded DNA, the two strands run in opposite directions, with the sugar-phosphate backbones facing outward. One strand is oriented 5' to 3' while the other runs 3' to 5'. This antiparallel arrangement is essential for proper base pairing—adenine pairs with thymine and cytosine pairs with guanine—so the helix can stabilize with uniform geometry. It also aligns with how DNA is replicated and transcribed, since polymerases add nucleotides to the 3' end and read templates in the 3' to 5' direction on the opposite strand. So the statement is true.