F2. Culture Media Preparation

Question 1

Solid, liquid or semi-solid [gelatinous in appearance] designed to support the growth of microorganisms

Answer 1

Culture Media

Question 2

Where to place?

Answer 2

1. Broth tube
2. Agar slant
3. Agar deep tube
4. Agar plate [petri plate]

Question 3

liquid
3 mL

Answer 3

Broth tube

Question 4

semi-solid
6 mL

Answer 4

Agar slant

Question 5

solidified
10 mL

Answer 5

Agar deep tube

Question 6

solid
15-20 mL

Answer 6

Agar Plate [Petri plate]

Question 7

Classification of agar according to consistency?

most commonly used as solidifying agent?

Answer 7

1. Solid
2. Liquid/ Broth
3. Semi-solid

Agar

Question 8

• 1.5-3% of agar
• solidifying agent is added
• will gelatinized once set in a room temperature

1. melting point?
2. resolidifying point?

Answer 8

Solid

1. greater than or equal to 95 degrees celsius
2. less than 50 degrees celsius

Question 9

Uses of solid agar?

Answer 9

1. surface growth of microorganisms to observe colony appearance
2. pure culture isolations
3. storage of culture [long-term storage]
4. To observe specific biochemical reactions

Question 10

completely dissolved in water & will never solidify

Answer 10

Liquid/ Broth

Question 11

Uses of liquid agar?

Answer 11

1. to propagate large numbers of microorganims in fermentation studies.
2. For various biochemical tests

Question 12

there is bacterial growth if it becomes?

Answer 12

turbid

Question 13

if the clarity is clear after you introduced the bacteria to a specimen then there is?

Answer 13

no bacterial growth

Question 14

• < 1.5% agar
• Solidify agent is added
• Has smaller concentration of agar compared to solid
• not as dense, do its purpose is to determine bacterial motility

Answer 14

Semi-solid

Question 15

Uses of semi-solid agar?

Answer 15

• fermentation studies
• determines bacterial motility
• promotes anaerobic growth

Question 16

Agar classification according to function?

Answer 16

1. enrichment media
2. selective media
3. enriched media
4. supportive/ nonselective medium
5. differential medium

Question 17

• Contains specific nutrients
• Used to enhance the growth of particular pathogen from a mixture of organism by using nutrient specificity

Answer 17

ENRICHMENT MEDIA

Question 18

• Favour the growth of a particular bacterium
• allow growth of desired bacteria
• inhibits the growth of undesired bacteria

Answer 18

SELECTIVE MEDIA

Question 19

Enriched usually by adding blood or eggs

Answer 19

ENRICHED MEDIUM

Question 20

Contain nutrients to support growth of most
nonfastidious organisms without giving any particular organism a growth advantage

Answer 20

SUPPORTIVE OR NONSELECTIVE MEDIUM

Question 21

Used to distinguish them from other bacteria growing on the same agar plate

Answer 21

DIFFERENTIAL MEDIUM

Question 22

Two types of container in culture media:

Answer 22

1. Tubed media
2. Plated media

Question 23

• semi-solid/ liquid
• steps for this culture media?

Answer 23

• tubed media
• Weigh, Dissolve, Dispense, Sterilize

Question 24

• solid
• steps for this culture media?

Answer 24

• plated media
• Weigh, Dissolve, Sterilized, Dispense

Question 25

• process of rendering a medium or material free of all forms of life

THREE BASIC WAYS OF STERILIZATION OF MEDIA?

Answer 25

STERILIZATION

1. autoclaving
2. ultraviolet radiation
3. ethylene oxide

Question 26

Exposure to steam at 121°C and 15 lbs of pressure of 15 minutes or longer, depending on the nature of the tem

will not survive longer than about 12 to 13 minutes

Answer 26

AUTOCLAVING

microorganisms & endospores

Question 27

Around 260nm is quite lethal to many organisms but does not penetrate glass, dirt films, water, and other substances very effectively

@ biosafety cabinet

Answer 27

ULTRAVIOLET (UV) RADIATION

Question 28

• Both microbicidal and sporicidal
• kills by covalently attaching to cell proteins
• particularly effective sterilizing agent because it rapidly penetrates packing materials, even plastic wraps

Answer 28

ETHYLENE OXIDE