Chapter 21, Problem 2STP

Summary Introduction

Introduction :

A virus is a nonliving strand of genetic material within a protein coat. Most biologists don’t consider viruses to be living because they do not exhibit all of the characteristics of life. Viruses have no organelles to take in nutrients or use energy, they cannot make proteins.

Answer to Problem 2STP

Correct answer :

The correct answer is option (C) a particular shape that matches the proteins on the surface of the host

Explanation of Solution

Explanation/justification for the correct answer :

Option (C) a particular shape that matches the proteins on the surface of the host. Attachment is accomplished when certain proteins on the target cell’s membrane bind to similar proteins called receptor proteins in the viral capsid. So, the correct answer is option (C).

Explanation for incorrect answer :

Option (A) DNA or RNA sequence that is recognized by the ribosomes of the host cell. Once virus successfully attaches to the host cell, the genetic material of the virus enters the cytoplasm of the host. So, this is an incorrect answer.

Option (B) the enzymes to burst the host cell so that the host cell can be used as raw materials. Sometimes the entire virus enters the cell and the capsid is broken down quickly, exposing the genetic material. The viral genes instruct the host cell to make more viral protein capsids and enzymes needed for viral replication. So, this is an incorrect answer.

Option (D) the proper enzyme to puncture the membrane of the host cell. Virus attach to the host cell when certain proteins on the target cell’s membrane bind to similar proteins called receptor proteins in the viral capsid. So, this is an incorrect answer.