Question at position 13 The enzyme _____________ is key to the high mutation rate observed in most retroviruses, like HIV. helicasereverse transcriptaseRNA transcriptaseDNA polymeraseInfectaseClear my selection单项选择题
A
helicase
B
reverse transcriptase
C
RNA transcriptase
D
DNA polymerase
E
Infectase

Question

Question at position 13 The enzyme _____________ is key to the high mutation rate observed in most retroviruses, like HIV. helicasereverse transcriptaseRNA transcriptaseDNA polymeraseInfectaseClear my selection单项选择题

A

helicase

B

reverse transcriptase

C

RNA transcriptase

D

DNA polymerase

E

Infectase

BlackTom AI · Accepted Answer

The question at hand asks which enzyme is key to the high mutation rate observed in most retroviruses, such as HIV, among the listed options.
Option 1: helicase. While helicase helps unwind nucleic acids during replication and transcription, it is not the main driver of the high mutation rate in retroviruses. Therefore this choice is not correct.
Option 2: reverse transcriptase. Retroviruses genetically carry reverse transcriptase to convert their RNA genome into DNA after infection. This enzyme is known to lack strong proofreading activity, which leads to a higher error rate during replication and thus a high mutation rate. This explanation aligns with established virology concepts, making this option correct.
Option 3: RNA transcriptase. There is no standard enzyme universally referred to as RNA transcriptase in the context of retroviral replication; the process is carried out by reverse transcriptase, not a distinct RNA transcriptase, so this choice is inaccurate.
Option 4: DNA polymerase. In many organisms, DNA polymerases have proofreading capabilities, reducing mutation rates. Retroviruses do not rely on host DNA polymerase for their replication; they use reverse transcriptase, which lacks robust proofreading. This option does not explain the high mutation rate in retroviruses.
Option 5: Infectase. There is no well-established enzyme named infectase involved in retroviral replication; this option is not a recognized contributor to mutation rates and is therefore incorrect.
In summary, among the options provided, reverse transcriptase best explains the high mutation rate observed in retroviruses due to its relatively low proofreading capability compared with other polymerases, while the other enzymes either do not play the central role or are not characteristic of retroviral replication.