Introduction: Culture Media Preparation and Sterilization

Question 1

What are the three types of media used according to consistency?

Answer 1

Liquid, semisolid, and solid media.

Question 2

What is the major difference between solid/semisolid media and liquid media?

Answer 2

Solid and semisolid media contain a solidifying or gelling agent (e.g., agar, gelatine), while liquid media do not.

Question 3

Give examples of liquid media.

Answer 3

Examples include nutrient broth, tryptic soy broth, and glucose broth.

Question 4

What are semisolid media used for?

Answer 4

Semisolid media are used in fermentation studies, determining bacterial motility, and promoting anaerobic growth.

Question 5

What are the main purposes of solid media?

Answer 5

Solid media are used for surface growth observation, pure culture isolation, bacterial enumeration and isolation, and observation of specific biochemical reactions.

Question 6

What are some examples of solid media?

Answer 6

Nutrient agar is a common example of solid media.

Question 7

How can solid media be poured?

Answer 7

Solid media can be poured into test tubes, Petri dishes, agar slants, agar deep tubes, or agar plates.

Question 8

What are the categories of media based on composition?

Answer 8

Media can be chemically defined/synthetic or complex/nonsynthetic.

Question 9

What are three commonly used components in complex media?

Answer 9

Beef extract, yeast extract, and peptone.

Question 10

What is the function of all-purpose media?

Answer 10

All-purpose media support the growth of most bacteria cultured in the laboratory without containing any special additives.

Question 11

What do selective media do?

Answer 11

Selective media enhance the growth of certain organisms while inhibiting the growth of others due to the inclusion of particular substrates.

Question 12

What is the purpose of differential media?

Answer 12

Differential media allow identification of microorganisms through visible physiological reactions unique to those bacteria.

Question 13

What are enrichment media used for?

Answer 13

Enrichment media allow metabolically fastidious microorganisms to grow due to the addition of specific growth factors.

Question 14

What is the function of enrichment culture?

Answer 14

What is the function of enrichment culture?

Question 15

What distinguishes agar slants from agar deep tubes?

Answer 15

Agar slants are tubes where the agar is allowed to harden in a slanted position, while agar deep tubes have agar hardened in an upright position.

Question 16

What is the designation for agar poured into a Petri dish?

Answer 16

Agar poured into a Petri dish is designated as an agar plate.

Question 17

What is the difference between chemically defined and complex media?

Answer 17

Chemically defined media are composed of known quantities of pure chemicals, while complex media are composed of complex materials with poorly defined chemical compositions.

Question 18

What are some examples of chemically defined media?

Answer 18

Examples include minimal media used in molecular biology and synthetic media used in industrial microbiology.

Question 19

What are the practical advantages of using media that both select for and differentiate common pathogens?

Answer 19

Such media allow for the identification of specific pathogens while inhibiting the growth of others, aiding in diagnostic processes.

Question 20

How do enrichment media differ from selective media?

Answer 20

Enrichment media provide specific growth factors to encourage the growth of fastidious microorganisms, whereas selective media contain substances to inhibit the growth of certain organisms while allowing others to thrive.