BIOLOGY
BIOLOGY
12th Edition
ISBN: 9781260169614
Author: Raven
Publisher: RENT MCG
bartleby

Concept explainers

bartleby

Videos

Question
Book Icon
Chapter 26, Problem 1U
Summary Introduction

Introduction: A type of RNA virus that inserts a copy of its genome into the DNA of an invaded host cell is called a retrovirus. Thereby, it changes the genome of the host cell. These viruses are composed only of RNA and not DNA. They possess specific enzymes that provide them the unique characteristics.

Expert Solution & Answer
Check Mark

Answer to Problem 1U

Correct answer: b. Because host cells’ genomes do not contain a gene encoding an enzyme that can make DNA from RNA.

Explanation of Solution

Reason for the correct answer:

Retroviruses possess the reverse transcriptase enzyme. This is because the genome of the host cell does not possess a gene encoding an enzyme that could convert DNA from RNA. The reverse transcriptase enzyme converts RNA genome into DNA.

Option b. is given as “Because host cells’ genomes do not contain a gene encoding an enzyme that can make DNA from RNA”.

Hence, the correct answer is option b.

Reasons for the incorrect answers:

Option a. is given as “because host cells make DNA from RNA only in G2 of the cell cycle, and HIV infects only during G1 of the cell cycle”.

This is not an appropriate option that describes the function of reverse transcriptase enzyme in the retrovirus. Therefore, option a. is incorrect.

Option c. is given as “Because HIV deletes large parts of the host cell genome upon infection, and that means there is a chance that host cell reverse transcriptase will be deleted”.

The presence of reverse transcriptase in retroviruses facilitates reverse transcription of RNA into DNA. Therefore, option c. is incorrect.

Option d. is given as “Host cells cannot make RNA from DNA”.

This is not an appropriate option for the necessity of the presence of the reverse transcriptase enzyme in a retrovirus. Therefore, option d. is incorrect.

Hence, options a., c., and d. are incorrect.

Conclusion

Thus, the reason for the need of retroviruses to contain the reverse transcriptase enzyme is that it would facilitate the reverse transcription of RNA into DNA.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
How does a retrovirus prepare its genetic material for incorporation into the host cell genome?   a. Host enzymes incorporate viral RNA directly into the genome.   b. Host enzymes covert viral RNA to double-stranded viral DNA.   c. Viral reverse transcriptase uses viral RNA to make double-stranded viral RNA.   d. Viral reverse transcriptase uses viral RNA to make double-stranded viral DNA.   e. Viral reverse transcriptase uses viral single-stranded DNA to make double-stranded viral DNA.
a. How are viral envelopes formed? Why are enveloped viruses that infect plants and bacteria rare? b. Outline the life cycle options of a temperate phage upon entering a host cell. c. Consider the 5 steps of a virus life cycle. List three structures and/or processes that are unique to viruses and would make good drug targets for an antiviral agent. Explain your rationale for each choice.
What is the function of reverse transcriptase in retroviruses? O A. It converts host cell RNA into viral DNA. B. It uses viral RNA as a template for making more viral RNA genomes. O. It translates viral RNA into proteins. D. It uses viral RNA as a template for DNA synthesis, that is, it makes complementary DNA.
Knowledge Booster
Background pattern image
Biology
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
  • Text book image
    Biology (MindTap Course List)
    Biology
    ISBN:9781337392938
    Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg
    Publisher:Cengage Learning
Text book image
Biology (MindTap Course List)
Biology
ISBN:9781337392938
Author:Eldra Solomon, Charles Martin, Diana W. Martin, Linda R. Berg
Publisher:Cengage Learning
What Is A Virus ? ; Author: Peekaboo Kidz;https://www.youtube.com/watch?v=YS7vsBgWszI;License: Standard YouTube License, CC-BY