Chapter 20, Problem 1SQ

Summary Introduction

Introduction: A genome of an organism is the entire set of DNA that it possesses. The genome that is composed of genes consists of all the information to construct and sustain an organism. The genetic material present in the genes (DNA or RNA) is responsible to pass the hereditary information to the daughter cells. Cells can have either DNA or RNA as the genetic material. A virus can have either DNA or RNA as the genetic material.

Answer to Problem 1SQ

Correct answer: DNA or RNA may be the genetic material of a virus.

Hence, the correct answer is option c.

Explanation of Solution

Reason for the correct answer:

Option c. is given as “a virus”. The virus is a tiny infectious agent that is alive only in the living cells and can replicate only using host replicating machinery. The virus can have both DNA and RNA as a genetic material.

Hence, the correct answer is option c.

Reasons for the incorrect answers:

Option a. is given as “a bacterium”.

Bacteria are the prokaryotes that carry either DNA as a genetic material. Bacteria lack the membrane-bound nucleus and contain free DNA or RNA in their cytoplasm. They do not contain RNA as a genetic material.

Hence, the correct answer is option a.

Option b. is given as “a viroid”.

This is incorrect. The viroids are the tiny infectious that consists of short RNA strand without a protein coat. They do not contain both DNA and RNA as genetic material.

Hence, option b. is incorrect.

Option d. is given as “an archaeon”.

Archaeon is the prokaryotes with a single-celled structure similar to bacteria. They contain DNA as their genetic material, not RNA.

Hence, option d. is incorrect.

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

Conclusion

The viruses are the only structure that has both RNA and DNA, as their genetic material. Others like bacteria, eukaryotic cell, and archaeon contain only DNA in their genome.