topic 6

Question 1

aseptic techniques

Answer 1

• all equipment (including agar + petri dishes) should be sterile
• flaming equipment in a bunsen flame ensures sterility
• inoculation should be done with a flamed instrument
• lids should be replaced as quickly as possible
• work near a bunsen burner flames
• disinfect surfaces

Question 2

why are aseptic techniques important

Answer 2

to prevent:
- potentially harmful microorganisms escaping from your cultures into air + infecting humans
- microorganisms in the air entering and contaminating your cultures

Question 3

what are the two types of culture techniques

Answer 3

• agar plate
• selective media

Question 4

agar plate

Answer 4

• contains nutrient agar
• molten agar is usually mixed with nutrient broth poured into a petri dish and allowed to set
• agar acts like a sponge to hold the nutrients in a solid block

Question 5

selective media

Answer 5

• can be used to grow specific types of organisms
• may rely on the addition or omission of a certain nutrient
• or include an antibiotic if the desired bacterium is known to be resistant