Question

question 21 of 73 Testion 21 1.25 points Save A Figure 62 Figure 6.2 shows a typical bacterial growth curve with the y-axis indicating the log of the number of bacteria and the x-axis indicating time in culture. In the figure, which sections of the graph illustrate a logarithmic change in cell numbers? a and be band d a and d cand d a and c

Answer 1

Q.22. Answer- b and d

Explanation-

1. Bacterial growth curve shows four phase - lag phase(a), log phase(b), stationary phase(c) and death phase(d). In this graph section b and d shows logarithmic change in cell number.

2. In section "a" of graph lag phase shows no increase in cell number as cells are not dividing but they take time to adapt new media conditions. So that in this phase there is no logarithmic change in cell number.

3. In second section of graph, "b" shows sharp increase in curve shows logarithmic increase in cell number as growth is not limited due to presence of plenty of nutrients. Due to high growth rate this phase is also known as exponential phase.

4. In third section of graph, "c" shows horizontal linear part of graph indicates no change in cell number as nutrients are depleted after log phase. In this phase growth rate and death rate is same so that cell number remains constant. In this phase there is no logarithmic change in cell number.

5. In last phase of graph, "d" shows decline in curve indicates decrease in cell number due to death of cells. The sharp decline in curve shows logarithmic decrease in cell number due to lack of nutrients.

6. In this typical bacterial growth curve section b and c illustrates a logarithmic change in cell number.

Q. Answer-

Disinfectants	Respective groups
5. Soap	5. Surfactant	soap acts as surfactant that helps to remove dirt and bacteria from skin
3. Bleach	3. Halogens	sodium hypochloride is component of bleach used to disinfect water and chlorine is halogen present in bleach
1. Nitrite	1. Chemical food preservative	sodium nitrite Is used as chemical food preservative
2. Isopropanol	2. Alcohol	isopropanol is isopropyl alcohol has alcohol functional group
4. Copper sulfate	4. Heavy metals	In copper sulfate copper is heavy metal