GENETICS AND EVOLUTION
MOLECULAR BASIS OF INHERITANCE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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in the 5’ to 3’ direction
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in the 3’ to 5’ direction
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in both the 3’ to 5’ and 5’ to 3’ directions from the replication fork.
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from one end to the other, in the 3’ to 5’ or the 5’ to 3’ directions
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Detailed explanation-1: -Figure 3: Replication of the leading DNA strand is continuous, while replication along the lagging strand is discontinuous. After a short length of the DNA has been unwound, synthesis must proceed in the 5’ to 3’ direction; that is, in the direction opposite that of the unwinding.
Detailed explanation-2: -New DNA is made by enzymes called DNA polymerases, which require a template and a primer (starter) and synthesize DNA in the 5’ to 3’ direction. During DNA replication, one new strand (the leading strand) is made as a continuous piece.
Detailed explanation-3: -The need for accuracy probably explains why DNA replication occurs only in the 5′-to-3′ direction. If there were a DNA polymerase that added deoxyribonucleoside triphosphates in the 3′-to-5′ direction, the growing 5′-chain end, rather than the incoming mononucleotide, would carry the activating triphosphate.
Detailed explanation-4: -RNA polymerase synthesizes an RNA strand complementary to a template DNA strand. It synthesizes the RNA strand in the 5’ to 3’ direction, while reading the template DNA strand in the 3’ to 5’ direction. The template DNA strand and RNA strand are antiparallel.