Question

1. TERT is the enzyme that works to solve the end replication problem in eukaryotes.

How does it do that?

a) TERT=telomerase reverse transcriptase. Why is this a reverse transcriptase? Explain

b) Does this conform to the basic DNA--> RNA--> protein dogma? Why?

Answer 1

A. Telomerase is a reverse transcriptase enzyme which helps to solve end replication problem in eukaryotes. Eukaryotic DNA is linear in shape and therefore after every round of DNA replication, the length of chromosome is shortened. If this will continue, then after repeated rounds of DNA replication, the chromosome will be loss and the cell will die. Therefore eukaryotes have developed an extensive mechanism of solving this problem. Eukaryotic cell have a special reverse transcriptase enzyme called as telomerase. This enzyme at repetitive sequences add the tips of chromosomes called as telomerase. The enzyme works in a reverse transcription manner and this is why the enzyme is a reverse transcriptase enzyme. It itself provides an RNA template for the synthesis of repetitive sequence of DNA. The process of formation of DNA from RNA is called as reverse transcription.

The working of enzyme telomerase does not go along with the central dogma of Molecular Biology. This is because according to this dogma, genetic information always flows from DNA to RNA and then to proteins. The working of telomerase is flowing from RNA to DNA and that is why it is called as reverse transcription.

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