Kinetics of Balanced Growth

Question 1

The rate of cell growth varies depending on the _______

Answer 1

growth phase

Question 1

The different phases of growth are more readily distinguished when the _______ of viable cell concentration is plotted against time

Answer 1

logarithm

Question 2

To find the relationship or graph of the cell concentration vs time, ______ plot is used

Answer 2

semi-log

Question 3

What are the six phases of cell growth

Answer 3

Lag phase, Acceleration, Growth phase, Decline phase, stationary phase, Death phase

Question 4

During the __________ immediately after inoculation of the culture, the rate of growth is
essentially zero

Answer 4

lag phase

Question 5

Lag phase refers to a period of time when the change of cell number is

Answer 5

zero

Question 6

Cells use the ________ to adapt to their new environment.

Answer 6

lag phase

Question 7

In this lag phase, new enzymes or structural components may be synthesized but the
concentration of cells ____________

Answer 7

does not increase

Question 8

The length of this lag period depends on many factors such as

Answer 8

the type and age of the microorganisms, the size of the inoculum, and culture conditions

Question 9

Growth starts for the inoculated cell culture

Answer 9

Acceleration phase

Question 10

At acceleration phase, the cell number starts to ______, and the division rate increases to reach a __________

Answer 10

increase, maximum

Question 11

During this period, growth achieves its maximum rate

Answer 11

Growth phase

Question 12

If growth is ___________ nutrient exhaustion or build-up of inhibitory products. (which is the most often case), the growth phase appears as a
straight line on a semi-log plot

Answer 12

exponential

Question 13

During decline phase, growth slows down due to____________

Answer 13

nutrient exhaustion or build-up of inhibitory products.

Question 14

During this period, cell growth ceases

Answer 14

Stationary phase

Question 15

No further cell growth can be observed.

Answer 15

Stationary phase

Question 16

The transition between the exponential phase and the stationary phase involves a period
of _____________

Answer 16

unbalanced growth

Question 17

cells in the stationary phase have a chemical composition _________ from that of cells in the exponential phase.

Answer 17

different

Question 18

At this phase, cells lose viability or are destroyed

Answer 18

Death phase

Question 19

During death phase, the cells are destroyed by _______

Answer 19

lysis

Question 20

Death occurs either because of

Answer 20

depletion of the cellular reserves of energy, or the accumulation of toxic products.

Question 21

cell growth is considered to be a

Answer 21

first-order autocatalytic reaction

Question 22

In a closed system where growth is the only process affecting cell concentration, the rate of growth 𝑟𝑁 is _______ to the rate of change of cell concentration

Answer 22

equal

Question 23

Cell growth rates are often expressed in terms of the _________

Answer 23

doubling time, 𝒕d

Question 24

time required for the cell population to double

Answer 24

doubling time, 𝒕d

Question 25

doubling time is a valid representation of the growth rate only when ____________

Answer 25

μ is constant.