Homework 7 Bme260 s16 Key

Homework 7 Name

1.

BME 260L KEY

DUE Tues. April 12th

A cell culture is initially composed of 100 cells. After 12 hours the number number of cells is 1.5 times the number number in the initial population. a. If the rate of growth is proportional to the number of cells present, determine the time necessary for for the number of cells to triple.  b. What is the time required for a culture with 1 x 106 of the same cells to triple? Explain your results. c. Under what conditions would the answers obtained in part b) be invalid?

2. For a specific type of cell after 3 hours, the concentration of cells per milliliter of solution is about 400/mL. After 10 hours the concentration has gone up to 2000/mL. Determine the initial concentration of cells.

3. Researchers found that in order to produce a recombinant protein from an E. Coli  population they needed a cell density of 400 million cells/L. How long would it take to reach this cellular density if the initial inoculation density was 10,000 cells/L the glucose concentration was 100g/L and a small concentration of Apoptosis Inducing Factor was seen in the growth medium of 5g/L? Use the following information. -1 k  p,max=1.3hr  -1 =0.02hr  -5 g/L K s =2.2x10 1 cell= 1ng

4. A strain of mold was grown in a batch culture on glucose and the following data were obtained: Time (hr) Cell Concentration (g/L) Glucose Conc. (g/L) 0

1.25

100

9

2.45

97

16

5.1

90.4

23

10.5

76.9

30

22

48.1

34

33

20.6

36

37.5

9.38

40

41

0.6

a. Find the specific growth rate ().  b. Find the maximum cell concentration that may be obtained i f 150 g/l of glucose were used with the same initial inoculum (at t=0)