Alcohol Fermentation.Lab WKST 6 PDF

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Name:

Destinee Logan

Cellular Respiration/Alcoholic Fermentation Lab Worksheet 1.

Complete the following table based on the results obtained from the experiments. Actual values are the graduated pipette readings. To obtain the carbon dioxide (CO2) evolved values, subtract the initial reading (I) from the actual reading (A). This is the amount of CO2 accumulated over time.

Table 1 Total CO2 Evolved by Different Concentrations of Yeast CO2

Tube 2 (I)

CO2

Tube 3 (I)

CO2

Tube 4 (I)

CO2

Tube 5 (I)

CO2

Tube 6 (I)

CO2

Actual (A)

Evolved (A-I)

Actual (A)

Evolved (A-I)

Actual (A)

Evolved (A-I)

Actual (A)

Evolved (A-I)

Actual (A)

Evolved (A-I)

Actual (A)

Evolved (A-I)

2

0

1

0

1

.02

.98

0

1

.04

.96

.2

.8

4

0

1

0

1

.02

.98

.02

.98

.2

.8

.37

.63

6

0

1

0

1

.08

.92

.05

.95

.3

.7

.5

.5

8

0

1

0

1

.09

.91

.08

.92

.35

.65

.56

.44

10

0

1

0

1

.09

.91

.1

.9

.4

.6

.64

.36

12

0

1

0

1

.09

.91

.12

.88

.42

.58

.66

.34

14

0

1

0

1

.1

.9

.13

.87

.43

.57

.76

.24

16

0

1

0

1

.1

.9

.14

.86

.45

.55

.72

.28

18

0

1

0

1

.1

.9

.15

.85

.47

.53

.77

.23

20

0

1

0

1

.1

.9

.16

.84

.5

.50

.76

.24

Time (min)

2.

Tube 1 (I)

Use Excel to construct a graph illustrating your results. a. What is the independent variable? Which is the appropriate axis for this variable? i. The independent variable in terms of the results of the experiment should be the amount of time that the tubes sat for, and the appropriate axis for this variable is the x-axis. b. What is the dependent variable? Which is the appropriate axis for this variable? i. The dependent variable should be the amount of CO2 produced in the tubes. The appropriate axis for this variable is the y-axis. c. Choose an appropriate scale and label the x- and y-axes. i. See Table Below d. Compose a figure title. i. See Table Below

Name:

Destinee Logan

Cellular Respiration/Alcoholic Fermentation Lab Worksheet Insert graph here:

Name:

Destinee Logan

Cellular Respiration/Alcoholic Fermentation Lab Worksheet Review Questions 1.

State your hypothesis. Was your hypothesis supported? Explain.

The more yeast and glucose in the tube, the greater the end concentration of CO2 should be in the tube because the yeast consumes the glucose and produces the CO2. This hypothesis was supported because as the amount of glucose and/or yeast increased in each tube, a higher yield of CO2 was found. 2.

Which tube was the negative control? Which ones are the positive controls? Explain.

The negative control was clearly the first tube because of the fact that it only consisted of glucose and water. This made it the negative control because there was no yeast in the tube to consume the glucose. The positive controls were the last tubes (tubes 5&6) because they clearly had very high concentrations of glucose and yeast. Therefore, it should have been obvious that the last two tubes were meant to produce the CO2. 3.

What does the difference in CO2 levels in the tube containing 1 mL of yeast versus that containing 3 mL of yeast tell you about alcoholic fermentation?

The rate of fermentation is faster if the CO2 production is greater. This is observed in the form of greater displacement of water in this experiment, in the tubes containing yeast. 4.

If this experiment were to be repeated, name two variables that can be manipulated to change the rate of alcoholic fermentation?

The two variables within this experiment that could be manipulated to change the rate of alcoholic fermentation are the amount of glucose in the water and the amount of yeast. 5.

Why were different amounts of water added to each fermentation solution?

Different amounts of water were added to each fermentation solution to make up for the different amounts of solution in each tube so that there would be the same amount in the tube. 6.

Explain why alcoholic fermentation is not the most efficient process for producing Adenosine Triphosphate (ATP)?

Alcoholic fermentation is the most efficient process for producing Adenosine Triphosphate because it is a passive process rather than an active process which means that it does not require energy to produce ATP. 7.

Draw the possible pathways during glucose metabolism in both aerobic and anaerobic respiration. Explain your answer.

8.

Why can’t yeast use glycolysis without alcoholic fermentation when oxygen (O2) is not available?

Alcohol fermentation is needed to make electron carriers which are needed to produce ATP when O2 is not available....