Lab 26, lab 30.1

Question 1

Bacteriophage infection pathways

Answer 1

lysis and lysogeny

Question 2

growing phages

Answer 2

plaques and cloudy vs clear

Question 3

(PFU)/ml meaning

Answer 3

Plaque- forming units

Question 4

Titer=

Answer 4

of plaques * 1 / dilution factor

Question 5

Viruses are:

Answer 5

unicellular, obligate intercellular parasites

Question 6

Viruses contain:

Answer 6

DNA or RNA which is their genetic material

Question 7

Genetic material is enclosed in a protein coat called

Answer 7

capsid

Question 8

the capsid may also contain a ____ or a ____

Answer 8

tail or a body through which genetic material is injected into the host.

Question 9

At the end of a virus there are tail fibers present which have the ability to attach to specific sites which are called

Answer 9

receptors

Question 10

Receptors are generally

Answer 10

proteins or glycoproteins

Question 11

viruses that infect bacteria are called

Answer 11

bacteriophage or simple phage ( phagein; to eat)

Question 12

phage which affects e.coli is called

Answer 12

coliphages

Question 13

Lytic phage:

Answer 13

causes lysis of the cell:
1. takes over the replicative machinery of the cell
2. uses those components to make a new phage -> mature phages
3. cell resources have been depleted
4. host cell burst
5. phage particles are released to infect bacterial cells

Question 14

lysogeny

Answer 14

Mostly follow the lysis cycle
Some do not form stable relationships with the host cell
phage incorporates into the genome of the host at a specific site

Question 15

Bacteriophage infections can be visualized by the

Answer 15

formation of plaques

Question 16

plaques are;

Answer 16

zones of clearing in bacterial lawns

Question 17

Lytic phages produce _____ plaques
why?

Answer 17

clear
due to the killing of the cells in the zone

Question 18

lysogenic phages give ____ plaques
why?

Answer 18

cloudy
growth of lysogens within the zone

Question 19

Plaques can be used to;

Answer 19

count the number of bacteriophage

Question 20

the number of bacteriophage in a sample is known as

Answer 20

titer

Question 21

Starch is a _____ _____ produced by _____

Answer 21

a complex carbohydrate , plants

Question 22

amylases:

Answer 22

enzymes which break down amylose and amylopectin to maltose, glucose and dextrins

Question 23

An indicator used is

Answer 23

iodine

Question 24

Eaten starch-clear area- no more starch

Answer 24

iodine will not turn the area black

Question 25

starch has not been metabolized

Answer 25

iodine will turn black