Chapter 18, Problem 21A

Summary Introduction

Introduction:

The viruses are the small pathogen having nucleic acids and a protein capsule around it. The virus reproduces in the cell of the host and they use the resource of the host cells.

Answer to Problem 21A

Correct Answer:

Option (A) Genetic material and a capsid.

Explanation of Solution

Explanation/justification for the correct answer:

Option (A) genetic material and capsid. The viruses are made up of genetic material, which is either DNA or RNA, the genetic material of the virus is enclosed within a protein membrane called capsid.

Explanation for incorrect answer:

Option (B) a nucleus, genetic material and capsid. The nucleus is the characteristic of eukaryotic cells. Inside the nucleus the genetic material of the cell is enclosed. Hence, it is an incorrect answer.

Option (C) a nucleus, genetic material, ribosomes and capsid. The viruses lack a nucleus and ribosome, these are characteristic of a cell and virus is acellular. Hence, it is not correct.

Option (D) a nucleus, genetic material, ribosome, plasma membrane and capsid. The virus is acellular and plasma membrane is the outer covering of cells. It is absent in viruses. Hence, it is an incorrect answer.