Microbiology

Question 1

Bacteriphage

Answer 1

A virus that infects a bacteria

Question 2

Capsid

Answer 2

Provides the external morphology that is used to classify viruses

Question 3

Hydrolase

Answer 3

A hydrolytic enzyme that degrades the entire host genome

Example of an early gene

Question 4

Early gene

Answer 4

Genes that are expressed immediately after injection and includes any special enzymes required to express viral genes

Question 5

Lysozyme

Answer 5

Destroys bacterial cell walls

Question 6

Steps of the lytic cycle

Answer 6

1. Attachment of phage to E.Coli and injection of phage chromosome
2. Breakdown of bacterial chromosomes by phage-specific enzyme
3. Replication of phage chromosome using bacterial methods and phage enzymes
4. Expression of phage genes to produce structural components
5. Assembly of phage particles
6. Release of progeny phage by lysis of bacterial wall

Question 7

The Lytic Cycle

Answer 7

An efficient way for a virus to rapidly increase its numbers

Host cells are destroyed

Question 8

The lysogenic cycle

Answer 8

Phage genome is incorporated into the bacterial genome

Question 9

Steps of the lysogenic cycle

Answer 9

1. The phage binds to the bacterium
2. The phage DNA enters the host cell
3. The phage DNA integrates and becomes a noninfective prophage
4. Chromosome with integrated prophage replicates
5. In rare cases, the prophage may separate and the cell be induced to lyse

Question 10

Endocytosis

Answer 10

A process whereby the host cell engulfs the virus and internalizes it

Question 11

Productive cycle

Answer 11

The same as the lytic cycle but does not destroy the host cell