TOPIC 4 Practicals

Question 1

What is the purpose of aseptic techniques?

Answer 1

to avoid contamination of sample from outside substances (e.g. microorganisms)

Question 2

Give 6 aseptic techniques

Answer 2

1. Wipe down surfaces with antibacterial cleaner (before and after experiment)
2. Use a Bunsen burner in work space (so convection current draws microbes away from culture)
3. Flame the wire loop (before using it)
4. Flame the neck of any bottles used
5. Keep all vessels containing bacteria open for minimum amount of time
6. Close windows and doors to limit air currents

Question 3

What does an increased area of the inhibition zone (clear zone) mean?

Answer 3

antimicrobial/ antibiotic has killed more bacteria = no antimicrobial resistance

Question 4

How can chance be removed from sampling process?

Answer 4

• using a large sample size
• analysis of data is collected (stats tests)

Question 5

Of a normal distribution curve, the mean and standard deviation make up what characteristics of the curve?

Answer 5

mean = maximum height of the curve
standard deviation = width of curve

Question 6

How much of the data lies within 1 SDV of the mean?

Answer 6

68%

Question 7

How much of the data lies within 2 SDVs of the mean?

Answer 7

95%