Quiz 1

Question 1

pure culture

Answer 1

a culture in which each cell is a direct descendent of a single cell from a culture containing cells of only one species

Question 2

purpose of a culture medium

Answer 2

to establish growth conditions which will selectively favour the microbe sought, obtaining an abundance of that microbe relative to other microorganisms present

Question 3

What is the yellow bacteria grown in this image of Experiment 1C?

Answer 3

Micrococcus luteus

Question 4

What is the red bacteria grown in this image of Experiment 1C?

Answer 4

Serratia marcescens

Question 7

agar

Answer 7

A complex polysaccharide, usually extracted from red algae, used as a solidifying agent in culture media.

Begins to harden around 40 - 42°C

Question 8

What gives Serratia marcescens its charachteristic red colour?

Answer 8

prodigiosin

Question 9

prodigiosin

Answer 9

Prodigiosin is the red pigment produced by many strains of the bacterium Serratia marcescens, other Gram-negative, gamma proteobacteria such as Vibrio psychroerythrus and Hahella chejuensis. It is in a family of compounds termed “prodiginines”, which are produced in some Gram-negative gamma proteobacteria, as well as select Gram-positive Actinobacteria (e.g. Streptomyces coelicolor). The name “prodigiosin” is derived from “prodigious” (i.e. something marvelous).

Question 10

punctiform

Answer 10

Question 11

entire

Answer 11

Question 12

undulate

Answer 12

Question 13

lobate

Answer 13

Question 14

filamentous

Answer 14

Question 15

serrate

Answer 15

Question 16

curled

Answer 16

Question 17

granular

Answer 17

Question 18

rhiziod

Answer 18

Question 19

punctiform

Answer 19

Question 20

flat

Answer 20

Question 21

raised

Answer 21

Question 22

convex

Answer 22

Question 23

pulvinate

Answer 23

Question 24

umbonate

Answer 24

Question 25

What colour is Serratia marcescens?

Answer 25

Normally red due to the pigment prodigiosin, but there are colourless mutants so colour should not be the sole basis for colony selection

Question 26

What is the purpose of flaming a tube opening?

Answer 26

Not sterilisation, but to warm the opening of the tube and create convection currents up and away from the opening. The warm air rising will help prevent the enterance of airborne contaminating bacteria.

Question 42

What adjectives are used to describe the surface of a colony?

Answer 42

Smooth, glistening

Rough

Wrinkled

Dry, powdery