Question

**Telomeres are one solution to what is called the "end replication problem" list two other ways that cells are viruses have solved or dealt with this problem.

Answer 1

Telomeres solve the end replication problem by ensuring chromosome ends are replicated. Two other solutions are Alternative Lengthening of Telomeres (ALT) in certain cells and Rolling Circle Replication in some viruses and plasmids. Circular DNA in prokaryotes also naturally avoids this problem.

Step-by-step explanation:

Telomeres provide one solution to the end replication problem by making sure that the chromosome ends are replicated without loss to the gene-coding DNA sequences. The end replication problem arises because DNA polymerase can only add nucleotides in one direction, and at the lagging strand, there is no place for a primer to be added at the very end of the chromosome during replication. As a result, the very ends of chromosomes tend not to be replicated fully in each cell division, leading to progressive shortening of the chromosome with each division.

Two alternative ways that cells or viruses have solved or dealt with this problem are:

1. Alternative Lengthening of Telomeres (ALT): Some cells use recombination-based mechanisms to lengthen telomeres without the use of telomerase. This process often involves copying telomeric sequences from one chromosome end to another.
2. Rolling Circle Replication: Used by some viruses and plasmids, this method involves the replication of circular DNA molecules allowing replication to proceed around the circle, thus avoiding the end replication problem altogether.

In addition to these strategies, it's important to note that some prokaryotic organisms contain circular DNA molecules, naturally circumventing the end replication problem.