Chapter 5

Question 1

Methods of measuring growth

Answer 1

MICROSCOPIC COUNTS (counting 123…) STANDARD PLATE COUNTS (serial dilutions) OPTICAL DENSITY (absorbance, uses light scattering to determine microbial population)

Question 2

Optical density and Absorbance

Answer 2

Optical density (OD) =Absorbance (ABS), OD600=OD595, more turbidity (cloudiness) more growth which means higher OD or absorbance value, does not distinguish between living or non living organisms

Question 3

Homogenize

Answer 3

Mix up

Question 4

Effects of pH on microbial growth

Answer 4

pH is the measure of hydrogen ion ACIDOPHILES (pH 5.5 below), ALKALIPHILES (8.5 above), NEUTROPHILES (pH 5.5-8.5)