Lecture 10

Question 1

What is exponential growth? generation? generation time? division rate?

Answer 1

Exponential growth - growth where the population doubles every unit of time
Generation (n)
generation time (g)
Division rate = 1/g

Question 2

What is the formulas to calculate the number of generations?

Answer 2

n = 3.3(logN - logN0); N = N02^n; g = t/n
N = number of cells at a given time
N0 = starting number of cells

Question 3

What are the four phases of growth (batch culture)?

Answer 3

1. Lag - cells are getting used to new environment
2. Exponential - rapid growth, generation time doubles every unit of time
3. Stationary - nutrients begin getting used up by cells, not much rapid growth
4. Death - no nutrient source left for cells to grow, number of cells begin to decline

Question 4

How is chemostat different from batch growth?

Answer 4

• used in labs that need cosntant supply of cell
• allow for control of growth rate, cell density, and extended growth
• there has to be the same vilume of medium being added and removed
• if not the cells could get washed out

washed out - too much nutrient

Question 5

What are the benefits of chemostats?

Answer 5

• constant supply of cells
• useful for ecological studues
• easy to enrich cells with different nutrients
• measure genetic variations/mutations
• steady state cells are the best cells to work within experiments