Methods of Measuring Growth

Question 1

True or false. The higher the OD, lesser light is absorbed.

Answer 1

False. The more the light is absorbed.

Question 2

Reduces bacterial load

Answer 2

Serial dilution

Question 3

Method in viable count in which culture and media are mixed

Answer 3

Pour-plate method (microaerophilic: reduced need for oxygen)

Question 4

Medium used in 3rd phase of most probable no. technique

Answer 4

Eosin Methylene Blue (EMB)

Question 5

Where to get samples for most probable no. technique

Answer 5

Water, food, air

Question 6

Three phases in most probable no. technique

Answer 6

Presumptive, confirmatory, completed

Question 7

Downside of direct cell count

Answer 7

Reveal higher no. compared to viable as it considers both dead and alive (great plate count anomaly)

Question 8

Medium used in 1st phase of most probable no. technique

Answer 8

Lauryl Sulfate Tryptone Broth (LSTB)

Question 9

Optical density measures

Answer 9

the amount of light unscattered

Question 10

Durham tubes are used to

Answer 10

Check turbidity

Question 11

The standard range in serial dilution

Answer 11

30 - 300

Question 12

No. of cells in grids in counted

Answer 12

Direct cell count

Question 13

What is measured in spectrophotometer?

Answer 13

Optical density (OD)

Question 14

Downside of spread-plate method

Answer 14

Affected by the environment

Question 15

Method in viable count in which agar is in plate already

Answer 15

Spread-plate method

Question 16

In direct cell counting, sample is placed into a?

Answer 16

Petroff-Hauser counting chamber (haemocytometer)

Question 17

Downside of serial dilution

Answer 17

Tedious process

Question 18

Solution for great plate count anomaly

Answer 18

Use highly selective media (depending on goal), vary culture conditions

Question 19

Advantage and disadvantage of spectrophotomerer

Answer 19

ADV: Quick (~10 mins.)
DIS: Counts dead cells

Question 20

Basis for results of most probable no. technique

Answer 20

Gas production, turbidity

Question 21

Types of diluent

Answer 21

NSS, PBS

Question 22

True or false. Colony growth on plate reflects no. of cells in sample.

Answer 22

True

Question 23

Use of membrane filters w/ specific pores

Answer 23

Filtration

Question 24

Medium used in 2nd phase of most probable no. technique

Answer 24

Brilliant Green Lactose Bile Broth (BGLB) [45 deg. C, 24H, turbidity]