Reverse transcriptase synthesizes __? a. DNA from RNA b. RNA from DNA c. positive RNA to negative RNA d. negative RNA to positive RNA
The Correct Answer and Explanation is:
Correct Answer: a. DNA from RNA
Explanation:
Reverse transcriptase is an enzyme that plays a crucial role in the replication of certain viruses, particularly retroviruses such as HIV. The primary function of this enzyme is to synthesize DNA from an RNA template. This process is known as reverse transcription. It is the reverse of the usual transcription process that occurs in cells, where DNA is used to make RNA.
In the case of retroviruses, the virus carries its genetic material in the form of RNA. When the virus infects a host cell, it uses reverse transcriptase to convert its RNA genome into complementary DNA (cDNA). This cDNA is then integrated into the host cell’s genome by another viral enzyme called integrase. Once integrated, the viral DNA can be transcribed and translated by the host cell’s machinery to produce new viral proteins and RNA genomes, leading to the production of new virus particles.
The discovery of reverse transcriptase was a significant scientific breakthrough because it challenged the previously accepted “central dogma” of molecular biology. The central dogma stated that genetic information flows from DNA to RNA to protein. Reverse transcriptase demonstrated that information can also flow from RNA back to DNA.
This enzyme is not only important in virology but also has applications in molecular biology and biotechnology. For instance, reverse transcriptase is used in laboratories to synthesize complementary DNA (cDNA) from mRNA during gene expression studies and in techniques such as reverse transcription polymerase chain reaction (RT-PCR).
In summary, reverse transcriptase synthesizes DNA from an RNA template, which is essential for the life cycle of retroviruses and widely utilized in molecular biology research. Therefore, option a. DNA from RNA is the correct answer.
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