Ex20 - Determination of a Bacterial Growth Curve: The Role of Temperature

What determines the effect of temp on bacteria?

The population growth rate

During the log/exponential growth phase, what happens to the population?

The cells is increasing at the fastest rate possible under the conditions

Generation/Doubling Time

the time it takes for one cell to divide into 2 cells (or the time required for the cell population double)

The _ the generation time, the _ the growth

shorter, faster

What is the growth of bacterial population determined by?

inoculating a growth medium with a few cells and counting the cells over time

What causes the transparent broth to appear turbid?

bacteria in suspension in the broth scatter light

Turbidity is measured by what?

spectrophotometer

Increasing turbidity indicates what?

growth

What corresponds to the changes in the logarithmic absorbance scale on the spectrophotometer?

changes in the number of cells

Growth curve

absorbance (y-axis) vs time (x-axis)

The rate of growth is indicated by?

the slope of the lines (faster growth = steeper slope)

minimum growth temperature

the lowest temperature at which a species will grow

optimum growth temperature

the temp where the species grows the best and fastest

maximum growth temperature

the highest temp where growth can occur

Heat increases

the rate of collisions between molecules which increases enzyme activity

Temperatures near max growth temp, growth _

ceases because of enzyme denatauration