Microbiology Unit 4

Question 1

Genetic elements that replicate independently of a cell’s chromosome but require a living host in order to replicate; infect all cell types; acellular infectious agents; can contain DNA or RNA

Answer 1

Virus

Question 2

complete virus particle (nucleic acid surrounded by a protein coat, and possibly external layers); the actual particle that moves from one host cell to another

Answer 2

Virion

Question 3

What is the Virion size range?

Answer 3

~10-2300 nm

Question 4

nucleic acid (DNA or RNA) with a protein coat and sometimes additional components

Answer 4

Nucleocapsid

Question 5

projections on nucleocapsid made from something similar to peptidoglycan

Answer 5

fibrils

Question 6

term for when a virus does not have an envelope

Answer 6

naked

Question 7

Most ____________ are classified as naked viruses.

Answer 7

bacteriophages

Question 8

Most _____________ are classified as enveloped.

Answer 8

animal viruses

Question 9

Three types of virus symmetry

Answer 9

helical, icosahedral and complex

Question 10

What is binal symmetry?

Answer 10

A virus with both icosahedral and helical symmetry (ex. T4 bacteriophage)

Question 11

what type of virus has positive sense and negative sense?

Answer 11

ssRNA viruses

Question 12

Positive Sense (+, plus strand)

Answer 12

genome and mRNA are the same sequence

Question 13

Negative sense (-, negative strand)

Answer 13

genome and mRNA are compliments

Question 14

what viruses consist of both ssRNA and dsDNA

Answer 14

animal viruses

Question 15

outer, flexible membranous layer; lipids and carbohydrates are host-derived

Answer 15

viral envelopes

Question 16

functions of the viral envelope

Answer 16

viral attachment to host cell, enzymatic activity, role in nucleic acid replication, identification of virus