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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The leading strand replicates in the 5’ to 3’ direction away the replication fork.
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The lagging strand replicates in the 5’ to 3’ away from the replication fork.
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The leading strand has special enzymes that make the process more efficient.
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The lagging strand is parallel to the leading strand.
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Detailed explanation-1: -In the leading strand, synthesis continues until the end of the chromosome is reached; however, on the lagging strand there is no place for a primer to be made for the DNA fragment to be copied at the end of the chromosome.
Detailed explanation-2: -The lagging strands have fragments of DNA which are called Okazaki fragments. The continual synthesis of the lagging strands is prevented by the original DNA orientation; this is the reason why the synthesis of the lagging strand is more complicated than the leading strand.
Detailed explanation-3: -For the lagging strand, the direction of nucleotide polymerization is opposite to the overall direction of DNA chain growth. Lagging-strand DNA synthesis is delayed because it must wait for the leading strand to expose the template strand on which each Okazaki fragment is synthesized.
Detailed explanation-4: -The leading strand is synthesized by adding nucleotides to the 3’ end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5’ end. The lagging strand is synthesized continuously, whereas the leading strand is synthesized in short fragments that are ultimately stitched together.
Detailed explanation-5: -Proteins bound on DNA also provide significant obstacles for DNA replication, as replication fork proteins can collide with them and become displaced from DNA. These include various DNA binding proteins such as the transcription machinery. Another physical barrier could be the DNA structure itself.