Biology
Biology
10th Edition
ISBN: 9780073383071
Author: Raven
Publisher: MCGRAW-HILL HIGHER EDUCATION
bartleby

Concept explainers

bartleby

Videos

Textbook Question
Book Icon
Chapter 27, Problem 1U

The reverse transcriptase enzyme is active in which class of viruses?

a. Positive-strand RNA viruses

b. Double-stranded DNA viruses

c. Retroviruses

d. Negative-strand RNA viruses

Expert Solution & Answer
Check Mark
Summary Introduction

Introduction:

A virus is a small infectious agent that can’t be seen through the naked eyes. Viruses are made up of protein coat in which their genetic material is present. The viruses contain either double stranded or single stranded DNA or RNA as their genetic material. Based on their genetic material David Baltimore classified viruses into seven different classes. The viruses also have ability to synthesize DNA from RNA with the help of an enzyme reverse transcriptase.

Answer to Problem 1U

Correct answer:

The retroviruses (class VI virus) contain an enzyme reverse transcriptase. Therefore, option c. is correct.

Explanation of Solution

Reason for the correct statement:

Retroviruses are classified under class VI virus. They are single stranded RNA viruses which replicate their genome through DNA intermediate. These viruses contain reverse transcriptase enzyme which synthesize their DNA from RNA. Later, these viruses integrate their genome into the host cell and start their infectious cycle inside the host.

Option c. is given as “Retroviruses”.

As “the reverse transcriptase enzyme active in class VI viruses which is also called as Retroviruses” is the right answer.

Hence, option c. is correct.

Reasons for the incorrect statements:

Option a. is given as “positive strand RNA viruses”.

The positive strand RNA viruses are classified under class IV. The sequence of their genomic RNA is same as the sequence of mRNA . Hence, they directly translate their genome and produce infectious protein. They do not contain reverse transcriptase enzyme for their infectious cycle. So, it is a wrong answer.

Option b. is given as “Double stranded DNA viruses”.

The double stranded DNA viruses are classified under class I viruses. They contain DNA as their genetic material. Thus, they do not contain reverse transcriptase enzyme. So, it is a wrong answer.

Option d. is given as “Negative strand RNA viruses”.

The negative strand RNA viruses are classified under class V virus. Their RNA genome sequence is complementary to the sequence of mRNA . The does not contain reverse transcriptase enzyme. So, it is a wrong answer.

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

Conclusion

The retroviruses are class VI viruses that contain a reverse transcriptase enzyme which synthesize DNA from RNA.

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
4. You find that all four flower color genes map to the second chromosome, and perform complementation tests with deletions for each gene. You obtain the following results: (mutant a = blue, mutant b = white, mutant c = pink, mutant d = red) wolod Results of Complementation tests suld Jostum Mutant a b с Del (2.2 -2.6) blue white pink purple Del (2.3-2.8) blue white pink red Del (2.1 -2.5) blue purple pink purple Del (2.4-2.7) purple white pink red C d Indicate where each gene maps: a b ori ai indW (anioq 2) .8
lon 1. Below is a pedigree of a rare trait that is associated with a variable number repeat. PCR was performed on individuals using primers flanking the VNR, and results are shown on the agarose gel below the pedigree. I.1 1.2 II.1 II.2 II.3 II.4 II.5 II.6 11.7 III.1 III.2 III.3 III.4etum A. (5 points) What is the mode of inheritance? B. (10 points) Fill in the expected gel lanes for II.1, II.5, III.2, III.3 and III.4 C. (5 points) How might you explain the gel results for II.4?
To study genes that create the purple flower color in peas, you isolate 4 amorphic mutations. Each results in a flower with a different color, described mutant a = blue mutant c = pink mutant b = white mutant d = red A. In tests of double mutants, you observe the following phenotypes: mutants a and b = blue mutants b and c = white mutants c and d = pink Assuming you are looking at a biosynthetic pathway, draw the pathway indicating which step is affected by each mutant. B. What is the expected flower color of a double mutant of a and c?
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
Concepts of Biology
Biology
ISBN:9781938168116
Author:Samantha Fowler, Rebecca Roush, James Wise
Publisher:OpenStax College
Text book image
Medical Terminology for Health Professions, Spira...
Health & Nutrition
ISBN:9781305634350
Author:Ann Ehrlich, Carol L. Schroeder, Laura Ehrlich, Katrina A. Schroeder
Publisher:Cengage Learning
What Is A Virus ? ; Author: Peekaboo Kidz;https://www.youtube.com/watch?v=YS7vsBgWszI;License: Standard YouTube License, CC-BY