Suppose that the replicating chromosome in the figure above is a linear chromoso
ID: 200866 • Letter: S
Question
Suppose that the replicating chromosome in the figure above is a linear chromosome, and the rightward moving fork reaches the end of the chromosome. Which newly synthesized strand is expected to experience the “end-replication problem” that is overcome by telomerase function?
Question 9 options:
the one made from the A* template strand
the one made from the B* template strand
both the one made from the A* template strand and the B* template strand
Neither newly synthesized strand will experience the “end-of-replication problem.”
None of the answer options is correct.
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Question 10 (1 point)
the one made from the A* template strand
the one made from the B* template strand
both the one made from the A* template strand and the B* template strand
Neither newly synthesized strand will experience the “end-of-replication problem.”
None of the answer options is correct.
A* 239 5 5" 3 Arrows indicate direction replication fork is moving.Explanation / Answer
In eukaryotes, leading and lagging strands of DNA are produced during the replication. DNA polymerase 1 can replace the internal RNA primers of lagging strand with DNA. These primers can be removed by DNA polymerase 1 as long as there is a 3’OH group preceding the primer.
However, the 5’ RNA primer cannot be replaced by the DNA polymerase due to lack of 3’OH. This problem is known as an end-replication problem, which is solved by telomerase. Hence, it is removed. A 3’ single stranded parental DNA is required to replace the 5’ primer by telomerase. Telomerase has an internal sequence that is a primer. It adds a telomeric sequence to the 3’ G-tail end of chromosome. Once the telomerase has extended the template, DNA primase, DNA polymerase III and ligase can complete the daughter strand.
The 3’-5’ strand of template DNA replicates to form the leading strand while the 5’-3’ template strand give rise to the lagging strand during DNA replication. The lagging strand faces the problem of end–replication problem. The A* strand runs from 5’ to 3’ direction. Hence lagging strand is made from it.
Right option is: The one made from A* template strand.
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