Question

question: a strand of dna is read from left to right, from the 5 end to the 3 end. how will its complimentary strand be read from left to right? answer options: select one of four from the 3 end to the 5 end from the 5 end to the 3 end from the 6 end to the 4 end from the 4 end to the 2 end

Explanation:

DNA strands are antiparallel, meaning if one strand runs 5' to 3', its complementary strand runs in the opposite direction (3' to 5'). When reading the complementary strand from left to right, it follows its own 5' to 3'? No, wait—wait, the original strand is read 5'→3' left to right. The complementary strand is antiparallel, so its 3' end is opposite the original's 5' end. So when reading the complementary strand left to right, we are moving from its 3' end to its 5' end? Wait, no—let's clarify. The two DNA strands are antiparallel: one is 5'→3', the other is 3'→5'. So if the original strand (left to right) is 5'→3', the complementary strand (left to right) would be 3'→5' (because their orientations are opposite). So the complementary strand, when read left to right, is from its 3' end to its 5' end. The other options (6'/4', 4'/2') are invalid as DNA ends are 5' and 3'. The "5'→3'" option would be parallel, which DNA isn't. So the correct option is "From the 3' end to the 5' end".

Answer:

A. From the 3' end to the 5' end