RP 6 Aseptic techniques

Question 1

Suggest why aseptic technique is necessary

Answer 1

• prevent contamination of cultures from environment which could nullify investigation
• environment not contaminated by potentially hazardous microorganisms

Question 2

Suggest why agar plate is labelled on underside

Answer 2

• lid could get lost

- culture is inverted during incubation so easier to identify is underside is labelled

Question 3

Suggest why the neck of bottle containing culture is flamed

Answer 3

• produces a convection current away from opening

- prevent entry of microorganisms

Question 4

Give ways in which aseptic conditions are maintained

Answer 4

• bench sprayed with disinfectant
• sterile pipette and spreader used
• Bunsen burner to flame inoculating loop and neck of bottle containing culture
• lid of agar plate lifted slightly and towards Bunsen burner
• wear gloves

Question 5

Suggest why two pieces of adhesive tape are used to seal agar plate as oppose to sealing around it

Answer 5

• allows free passage of air

- normal growth (rather than promoting growth of anaerobic bacteria)

Question 6

Suggest why agar plates are incubated upside down

Answer 6

Prevents droplets of moisture which form during incubation falling on culture

Question 7

Why would wearing gloves maintain sterile conditions

Answer 7

Prevents contamination of hands with bacteria