17. List the four phases of growth that bacterial cultures undergo? Include what

Question

17. List the four phases of growth that bacterial cultures undergo? Include what is happening at each phase b. 2 ?.3. d. 4 18. What are some applications for using a growth curve? 19. List three ways to estimate the size of a population of bacteria a. b. 2 ?.3. 20. What does the increase in turbidity represent when using a spectrophotometer? 21. What is a drawback of the direct cell count? 22. How does a Coulter counter count the number of cells in a population? 23. Why is a viable plate count more accurate than a Coulter counter estimate? 24. When is counting bacteria by filtration used? 25. Give a real-life example of when counting bacteria by filtration is used?

Explanation / Answer

17.

a. 1. Lag phase: Bacterial cells adapt to the new environment after inoculation into the culture medium. They prepare essential enzymes and factor required for their division and growth. A very little or not growth is observed.

b. 2. Log/exponential phase: Bacterial cells start growing rapidly at thier maximum speed. The fastest increasing cell density or number is observed during this phase (growth rate is maximum). Primary metabolites are formed during this phase.

c. 3. Stationary phase: The cells start dying due to high dumebsuty and consumption of nutrients. In this phase growth rate equals death rate resulting in no net change in cell density (density remains constant during this phase). Secondary metabolites are formed during this phase.

d. 4. Death/decline phase: Nutrients are exhausted till this phase, and death rate becomes higher than growth rate resulting in decline in the cell culture density.

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.