6d Culturing Microorganisms (triple only)

Question 1

Name the process used by bacteria to reproduce

Answer 1

Binary fission

Question 2

How frequently can bacteria reproduce given ideal conditions?

Answer 2

Every 20 minutes

Question 3

Name the two mediums that can be used in the lab to culture bacteria

Answer 3

Nutrient broth

Agar gel plate

Question 4

Describe how an uncontaminated couture of bacteria can be prepared using aseptic techniques

Answer 4

Sterilise petri dish

Sterilise culture media (agar gel or nurtient broth)

Sterilise inoculating loop by passing through a flame

Use inoculatinf loop to trasnfer micororganisms to the sterile medium

Secure the lid of Petri dish with adhesive tape

Store plate upside down

Incubate at 25^oC

Question 5

Why is the petit dish sealed with two pieces of adhesive tape?

Answer 5

Secures lid

Allows oxygen to diffuse into the Petri dish

Question 6

State the nutrients found in culture medium

Answer 6

Water
Glucose
Amino acids
Minerals

Question 7

The picture shows an incubated petri dish containing bacteria

What is the name given to the ‘dots’ of bacteria?

Answer 7

Colony

Question 8

Why are school unable to incubate bacterial cultures at 37^oC

Answer 8

Human pathogens would grow and increase in numbers

Question 9

What is the name of the clear area around the filter paper discs on the plate?

Answer 9

Zone of inhibition

Question 10

How could the area of the zone of inhibition labelled A be calculated?

Answer 10

Measure the diameter of the inhibition zone

Divide by 2 to get the radius

Use the equation

πr2