Answers to Growth Questions:

1. 1000 x 2⁶ = 1000 x 64 = 64000 cells

2. n1 = 5281 and log n1 = 3.723

n2 = 6.145 x 10⁷ and log n2 = 7.788 n2 - n1 = 7.788 - 3.723 = 4.065

4.065 / 0.301 = 13.51 600 min / 13.51 gen = 44.4 min/gen

3. n1 = 10 and log n1 = 1.0

n2 = 62380 and log n2 = 4.80 n2 - n1 = 4.80 - 1.0 = 3.80

3.80 / 0.301 = 12.62 gen 240 min / 12.62 gen = 19 min/gen

60 min more; 60 min / 19 min/gen = 3.15 gen

62380 x 2^3.15 = 553719 = 5.54 x 10⁵ cells

4. 0.1 mL of 3.2 x 10⁴ cells/mL = 3.2 x 10³ cells

240 min / 18.4 min/gen = 13 gen

3.2 x 10³ cells x 2¹³ = 26214400 or 2.62 x 10⁸ cells

5. 2⁶⁰ = 1.53 x 10¹⁸ cells

6. 1500 x 2⁸ = 384000 = 3.84 x 10⁵ cells

7. 1.0 mL of a 1:100 dilution = 136; 136 / 10^-2 d.f. = 1.36 x 10⁴ = n1

214 / 10^-4 d.f. = 2140000 = 2.14 x 10⁶ = n2

log n1 = 4.13 log n2 = 6.33 6.33 - 4.13 /0.301 = 7.31 gen

180 min / 7.31 gen = 24.6 min/gen

8. 0.1 mL of a 2.46 x 10⁵ cells/mL = 2.46 x 10⁴ cells

180 min / 30 min/gen = 6 gen

2.46 x 10⁴ cells x 2⁶ = 1.57 x 10⁶ cells in culture

9. control

n1 = 200 and log n1 = 2.30

n2 = 1000000 and log n2 = 6. n2 - n1 = 6.0 - 2.3 = 3.70

3.70 / 0.301 = 12.3 gen 1740 min / 12.3 gen = 141.4 min/gen

experimental

n1 = 700 and log n1 = 2.85

n2 = 61000000 and log n2 = 7.78 n2 - n1 = 7.78 - 2.85 = 4.93

4.93 / 0.301 = 16.38 gen 1920 min / 16.38 gen = 117.2 min/gen

Additive does not work and in fact seems to promote growth

10. 0.1 mL sample of the final dilution produces 56 colonies; 56/0.1 mL = 560 cells/mL

d.f. = 1:100 x 1:100 x 1:10 = 10^-5

560 / 10^-5 = 5.6 x 10⁷ cells/mL in orig culture