MICROBIAL GROWTH I

Question 1

Explain all step in binary fission

Answer 1

1. DNA replicates
2. Cell elongation
3. Septum Formation
4. Completion of septum and with formation of distinct wall
5. Cell separation

Question 2

states all stages in growth curve

Answer 2

1. lag phase
2. exponential phase
   3.stationary phase
3. death phase

Question 3

what happen at lag phase

Answer 3

• cell adapt themselves to growth conditions and synthesising new components
  -no cell division occur
  -varies in length that even some are absent

Question 4

what happen at exponential phase

Answer 4

-known as log phase
-max rate of division and population growth
-doubling cell occurs at constant rate
-population is most uniform in terms of chemical properties and physical
-continuous growth will soon ceases when ran out of nutrients
-rate of growth is exponentially and constant

Question 5

what happen at stationary phase

Answer 5

• total number of viable cell remains constant because metabolically active cell stop reproducing or reproductive rate is balanced by death rate

Question 6

definition of doubling time

Answer 6

time required for the population to double in size (biomass) or number

Question 7

how to measure the microbial growth?

Answer 7

-measure changes:
i)in number of cells in a population
ii)in mass of population

Question 8

at which phase cell exhibit balanced growth

Answer 8

exponential phase

Question 9

reasons entry of stationary phase

Answer 9

1) limited O2
2) limited nutrients
3) accumulation of toxic cell
4) CRITICAL POPULATION DENSITY REACHED