From TA: Dharshani Nanayakkara
Page 1 of 4
BIOL 251 Lab Practicum I – Study Guide Part II
Review the quizzes and the lab reports, especially the review questions!!!
1. If the initial cell concentration is 5 x 109 cells/ml and the final concentration is 5 x 104
cells/ml, what is the dilution factor?
2. Determine the individual and total dilution factors in the following dilution scheme.
1mL
2mL
1mL
2mL
0.1mL
0.5mL
1mL
0.1mL
1mL
1mL
1mL
99mL
18mL
99.9mL
4.5
mL
Individual DF
Total DF
3. Fill in the missing information in the following dilution scheme.
1mL
1mL
0.01mL
0.1mL
mL
2mL
0.1mL
1mL
1mL
1mL
9mL
4.5mL
mL
Individual DF
Total DF
10 -3
10 -1
9.9
mL
From TA: Dharshani Nanayakkara
Page 2 of 4
4. How many bacteria were there in 1 ml of the original sample?
2mL
1mL
0.1mL
2mL
1mL
1mL
0.5mL
0.1mL
1mL
1mL
1mL
18mL
9.9mL
99mL
4.5
mL
180
colonies
5. Use the following data to construct a bacterial growth curve by plotting absorbance against
time. Use semi-log graph paper.
a. Identify and label the growth phases on the graph.
b. Calculate the generation time/doubling time (g) from the graph.
Time in minutes
0
60
120
180
240
300
360
420
Absorbance at 600 nm
0.043
0.044
0.092
0.147
0.330
0.606
0.925
0.880
From TA: Dharshani Nanayakkara
Page 3 of 4
6. Use the following data to construct a bacterial growth curve by plotting absorbance against
time. Use the semi-log graph paper.
a. Identify and label the growth phases on the graph.
b. Calculate the generation time/doubling time (g) from the graph.
Time in hours
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
5.00
5.50
6.00
6.50
7.00
7.50
8.00
8.50
9.00
9.50
10.00
10.50
11.00
11.50
12.00
12.50
Absorbance at 600 nm
0.007
0.007
0.008
0.008
0.010
0.014
0.022
0.032
0.046
0.066
0.109
0.164
0.241
0.338
0.518
0.754
1.094
1.558
1.887
2.005
2.163
1.985
2.116
2.114
1.995
2.028
From TA: Dharshani Nanayakkara
Page 4 of 4
7. Use the following data to construct a bacterial growth curve by plotting absorbance against
time. Use the semi-log graph paper.
a. Identify and label the growth phases on the graph.
b. Calculate the generation time/doubling time (g) from the graph.
Time in hours
0.00
0.75
1.50
2.25
3.00
3.75
4.50
5.25
6.00
6.75
7.50
8.25
9.00
9.75
10.50
11.25
12.00
12.75
13.50
14.25
15.00
15.75
16.50
17.25
18.00
18.75
Absorbance at 600 nm
0.003
0.003
0.004
0.004
0.005
0.006
0.010
0.015
0.025
0.039
0.065
0.102
0.164
0.300
0.443
0.681
1.079
1.377
1.668
2.936
2.242
2.044
2.085
2.113
2.264
2.206