Question

In switch sequences, there are sites that attract which enzyme?

a) DNA polymerase
b) RNA polymerase
c) Activation-induced cytidine deaminase (AID)
d) Helicase

Answer 1

RNA polymerase binds to switch sequences to initiate transcription, while DNA ligase would be the enzyme mutated if the joining of Okazaki fragments is impaired. Telomerase maintains the ends of linear chromosomes, and reverse transcriptase is brought into a cell by HIV.

Step-by-step explanation:

In switch sequences, the sites that attract RNA polymerase are responsible for initiating the transcription of DNA into RNA. When isolating a cell strain where joining of Okazaki fragments is impaired, the enzyme most likely to be mutated would be DNA ligase, which is essential for sealing the nicks between Okazaki fragments during DNA replication. The sequences to which RNA polymerase binds are known as promoters, which are a specific sequence of DNA nucleotides.

Moreover, the ends of linear chromosomes are maintained by the enzyme telomerase. During DNA replication, which takes place in the 5' to 3' direction, the enzyme primase synthesizes a primer to provide a starting point for DNA polymerase. In addition, HIV brings an enzyme called reverse transcriptase into the cell, which uses RNA as a template to produce a DNA copy.