Concept explainers
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
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
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
Hence, options a., b. and d. are incorrect.
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?
Chapter 27 Solutions
BIO 1406/07 W/CONNECT/LM NEW >IC<
- Which receptors of the infl uenza virus are responsible for binding to the host cell? a. hemagglutinin c. type A b. neuraminidase d. capsid proteinsarrow_forwardAt which stage in viral replication does the genetic information enter the host cell? a. Penetration c. Assembly b. Synthesis d. Releasearrow_forwardYou are treating a patient with antiviral agent against the nucleocapsid, what part of the virus will be destroyed? a. Enveloped b. Cytoplasm c. Capsid and genetic material d. Genetic materialarrow_forward
- A virus is isolated, and individual virions appear spherical. What type of virus is this? A. Bacteriophage B. Helical C. Icosahedral D. Lysogenicarrow_forwardChoose the combination of answers that most accurately completes the statement.The envelope of an animal virus is derived from the of its host cell. a. cell wall c. glycocalyx b. membrane d. receptorsarrow_forwardWhat's the term to describe a mutant viral protein, apart from any genetic material, that can cause disease?O A. VirusO B. VirionO C. ViroidO D. Prionarrow_forward
- Which of these is not a general pattern of virus morphology?a. enveloped, helical b. naked, icosahedral c. enveloped, icosahedral d. complex, helicalarrow_forwardGive an example of each of the following types of viruses a. Double stranded DNA b. Single stranded DNA c. Positive sense RNA d. Negative sense RNA e. Retrovirusesarrow_forwardChoose the combination of answers that most accurately completes the statement.Which of the following effects do antiviral drugs not have? a. killing extracellular viruses c. inhibiting virus maturation b. stopping virus synthesis d. blocking virus receptorsarrow_forward
- Select a drug or drugs that can prevent a viral nucleic acid from beingreplicated.a. retrovir b. acyclovir c. saquinavir d. both a and barrow_forwardUse the diagrams to answer the following question. Diagram 1 Diagram 2 Students are debating about differences between viruses and cells. Which student's argument is MOST correct using evidence from the diagrams? O A. Diagram 1 represents a cell and Diagram 2 represents a virus because viruses have a protein capsid while cells have a lipid membrane. O B. Diagram 1 represents a virus and Diagram 2 represents a cell because viruses do not have nucleic acids but cells do. O C. Diagram 1 represents a cell and Diagram 2 represents a virus because a virus has nucleic acids and cells do not. O D. Diagram 1 represents a virus and Diagram 2 represents a cell because cells have ribosomes to make their own proteins and viruses do not.arrow_forwardPenicillin is an antibiotic that acts by inhibiting the formation of peptidoglycan cross-links in a cell wall. Based on what you know about the nature of viruses and bacteria, will penicillin effectively kill the rhinovirus or coronavirus? Please explain your reasonarrow_forward
- Medical Terminology for Health Professions, Spira...Health & NutritionISBN:9781305634350Author:Ann Ehrlich, Carol L. Schroeder, Laura Ehrlich, Katrina A. SchroederPublisher:Cengage LearningConcepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax College