Patterns Of Growth

Question 1

What is growth?

Answer 1

The irreversible increase in dry mass that occurs when the rate of synthesis is greater than the rate of break down

Question 2

What is generation time?

Answer 2

The time taken for a population of unicellular organisms to double in number

Question 3

What are the 4 phases of growth

Answer 3

Lag
Log(exponential)
Stationary
Death

Question 4

Viable cell count

Answer 4

Number of cells alive and capable of reproduction

Question 5

Total Cell Count

Answer 5

All cells dead or alive

Question 6

Lag phase

Answer 6

Little or no increase in cell number

Cells adjust to growth medium

Enzymes are induced for use in metabolising new substrates

Question 7

Log Phase

Answer 7

Cells grow and multiply at maximum rate

Question 8

Stationary phase

Answer 8

Nutrients run out

Secondary metabolites produces by the microbes build up and can have a toxic effect

Rate of production of new cells = death rate of old cells

Question 9

Death phase

Answer 9

Number of cells dying exceeds the number of new cells being produced

Cells die at a constant rate and may undergo lysis (bursting)