BIO204 Midterm Slides

What is

Kinetics?

Growth → Change in state/number/ size/volume or in other sense it is the ratio between birth (B) and death (D).

What is

Kinetics?

Growth kinetics

refers to the change in number or size of organisms with respect to time. END

Turbiditimetric Method

•  A spectrophotometer is used to determine turbidity ("cloudiness") by measuring the amount of light that passed through a suspension of cells.
•  More cells→ more turbidity;
•  more turbidity→ less light passing through the suspension
•  %T is percent transmission - fewer cells present (less turbidity) will allow more light to pass through, the %T is higher when the cell number is lower.
•  Absorbance is the opposite of %T.

or

(Lambert-Beer Law)

Measure of Turbidity by using Spectrophotometer

•  Cell growth is also measured by counting total cell number of the microbes present in that sample. Total cells (both live and dead) of liquid sample

are · counted · by · using

a Haemocytometer/Neubauer Chamber.

•  If there is dilute culture, direct cell counting can be done. However, the cell culture of high density can be diluted. Otherwise clumps of cells would be formed which would create problem in exact counting of bacterial cells.