Question

Reverse transcriptase assembles a(n) a(n) ________template. a. mRNA; DNA c. DNA; ribosome b. \(\mathrm{CDNA} ; \mathrm{mRNA}\) d. protein; mRNA

Short answer

The correct answer is b: cDNA; mRNA.

Step-by-step solution

Identify the Function of Reverse Transcriptase

Reverse transcriptase is an enzyme that synthesizes DNA from an RNA template, making it crucial in processes like the replication of retroviruses.

Exploring the Role of Reverse Transcriptase

The primary role of reverse transcriptase is to convert RNA sequences into DNA sequences. This is characteristically observed in retroviruses, where the RNA genome is reverse-transcribed into DNA.

Match the Options to the Function

Given that reverse transcriptase synthesizes DNA using an RNA template, identify the option that correctly describes this process. Option (a) suggests that mRNA is used to make DNA, but it is incomplete. Option (b) correctly matches the function as it uses RNA to produce cDNA. Option (c) does not involve RNA or DNA synthesis. Option (d) incorrectly suggests protein is involved in mRNA synthesis.

Select the Correct Option

The correct template for reverse transcriptase to work with and the resultant product is option (b): it uses mRNA to make cDNA.

Key concepts

RNA Template

Understanding the role of an RNA template is crucial to comprehending how reverse transcriptase functions. An RNA template refers to an RNA strand that serves as a blueprint for the synthesis of complementary DNA (cDNA). In several biological processes, RNA molecules guide the assembly of new strands of nucleic acids, acting as a guide or template.

In the specific process involving reverse transcriptase, the RNA template facilitates the conversion of RNA-based information into a DNA-based format. This is a reversal of the usual process where DNA is typically transcribed into RNA, hence the enzyme's name—reverse transcriptase.

• The RNA template carries the genetic information that the reverse transcriptase enzyme reads.
• This reading is integral for crafting the complementary DNA strand.
• An RNA template ensures that the genetic information is precisely transferred from RNA to DNA.

Understanding this is essential since it highlights how molecular information can move from RNA sequences back to DNA, playing a pivotal role in processes such as viral replication.

cDNA Synthesis

cDNA synthesis is a fundamental process where complementary DNA (cDNA) is generated from an RNA template. This transformation is crucial when there's a need to analyze genetic information stored in RNA.

The synthesis of cDNA involves utilizing the RNA template as a guide for creating a DNA strand that is complementary to the RNA. This process is highly significant in molecular biology and biotechnology, facilitating the study of gene expression and viral replication in retroviruses.

Several key steps are involved in cDNA synthesis:

• Firstly, the RNA template binds to the reverse transcriptase enzyme.
• The enzyme then begins to synthesize a DNA strand that matches the base sequence of the RNA template.
• The result is a DNA strand that is complementary to the RNA, hence termed complementary DNA or cDNA.

This cDNA can then be used in a variety of molecular biology applications, such as cloning, sequencing, and analysis of gene expression patterns. By understanding cDNA synthesis, one appreciates how information in RNA form can be converted back into DNA format.

Retroviruses Replication

Retroviruses, such as HIV, are fascinating organisms that utilize reverse transcriptase for replication. These viruses have RNA as their genetic material, unlike many organisms that store genetic information as DNA.

During retrovirus replication, the RNA genome of the virus is transcribed into DNA by the reverse transcriptase enzyme. This newly synthesized viral DNA is then integrated into the host cell's genome. The process allows the virus to hijack the host's cellular machinery to produce new viral particles.

• This replication cycle begins with the entry of the viral RNA into the host cell.
• Once inside, reverse transcriptase converts the viral RNA into complementary DNA (cDNA).
• The cDNA integrates into the host's DNA, where it is expressed to produce new viral components.

Understanding this replication cycle is critical in developing therapies for retroviral infections, as inhibiting the action of reverse transcriptase can prevent the virus from replicating. Insights into how retroviruses replicate help researchers design drugs that can effectively combat diseases caused by these pathogens.