Anaerobic Fermentation
Part 1: Introduction
Pre-Lab Questions
1. Why is cellular respiration necessary for living organisms?
Cellular respiration is vital as it converts nutrients into ATP, the energy currency of cells. ATP powers
essential processes like metabolism, growth, movement, and maintenance of homeostasis. Without
cellular respiration, living organisms couldn't generate the energy needed for survival and functioning.
2. What happens in glycolysis? Who does glycolysis?
Glycolysis is a central metabolic pathway that is used by all cells for the oxidation of glucose to generate
energy in the form of ATP (Adenosine triphosphate) and intermediates for use in other metabolic
pathways. Glycolysis is a universal process that takes place in almost all living things, including bacteria,
archaea, plants, and animals. It is a crucial stage in cellular respiration and offers the first energy output
from glucose metabolism.
3. How much ATP is made during oxidative phosphorylation?
Approximately 28 to 34 molecules of ATP are generated per molecule of glucose
4. How much ATP is made during fermentation?
Two molecules of ATP per molecule of glucose.
5. Why is fermentation less effective than respiration?
Fermentation is less effective than respiration because it produces fewer ATP molecules from glucose,
lacks the efficiency of the electron transport chain, and does not fully oxidize glucose, leading to less
energy production.
6. What do we mean when we say the testing conditions are “anaerobic”?
When testing conditions are "anaerobic," it means that the environment lacks oxygen. This term is used
to describe processes or experiments occurring in the absence of oxygen
7. What are two industrial applications for fermentation?
Fermentation has various industrial applications, and two notable examples are:
Production of biofuels: Fermentation is used to convert biomass (such as corn or sugarcane) into
biofuels like ethanol, which can be used as an alternative to gasoline.
Food and beverage production: Fermentation is essential in making products like bread, yogurt, beer,
and cheese by utilizing microorganisms to transform raw materials.
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, Anaerobic Fermentation
Part 2: Fermentation in Yeast
8. What is your hypothesis for this lab?
Carbon dioxide is produced when yeast ferments sucrose, there will be a noticeable shift in the amount
of air in the test tube. Compared to sucrose, artificial sweeteners like saccharin and stevia have a
reduced fermentability, thus when yeast interacts with them, the air space change will be modest. Since
yeast needs sugar to ferment, there won't be much of a change in the air space if it is exposed to warm
water without any sugar.
9. When yeast cells ferment, they split sugar into two products. What are those two products?
Ethanol and Carbon dioxide will be produced.
10. If fermentation is working, the little air space in the small test tube will start to grow and push the
yeast out into the larger test tube. What substance is in the growing air space?
If fermentation takes place, carbon dioxide will probably start to fill the expanding air space in the tiny
test tube. Given that it is a byproduct of yeast fermentation and that its creation causes the air space to
expand, the yeast mixture may be forced into the larger test tube.
Results
Table 1: Times at each interval for each experimental condition
Time Sugar Saccharin Stevia Water
Start time 3:30 3:35 3:40 3:45
15 minutes 5mm 0.5 mm 0 mm 0 mm
30 minutes 8.5 mm 1mm 0 mm 0 mm
Table 2: Air space size at each time interval, recorded in millimeters (mm)
This study source was downloaded by 1143875 from cliffsnotes.com on 08-10-2025 19:04:08 GMT -05:00
https://www.cliffsnotes.com//study-notes/3162431
Part 1: Introduction
Pre-Lab Questions
1. Why is cellular respiration necessary for living organisms?
Cellular respiration is vital as it converts nutrients into ATP, the energy currency of cells. ATP powers
essential processes like metabolism, growth, movement, and maintenance of homeostasis. Without
cellular respiration, living organisms couldn't generate the energy needed for survival and functioning.
2. What happens in glycolysis? Who does glycolysis?
Glycolysis is a central metabolic pathway that is used by all cells for the oxidation of glucose to generate
energy in the form of ATP (Adenosine triphosphate) and intermediates for use in other metabolic
pathways. Glycolysis is a universal process that takes place in almost all living things, including bacteria,
archaea, plants, and animals. It is a crucial stage in cellular respiration and offers the first energy output
from glucose metabolism.
3. How much ATP is made during oxidative phosphorylation?
Approximately 28 to 34 molecules of ATP are generated per molecule of glucose
4. How much ATP is made during fermentation?
Two molecules of ATP per molecule of glucose.
5. Why is fermentation less effective than respiration?
Fermentation is less effective than respiration because it produces fewer ATP molecules from glucose,
lacks the efficiency of the electron transport chain, and does not fully oxidize glucose, leading to less
energy production.
6. What do we mean when we say the testing conditions are “anaerobic”?
When testing conditions are "anaerobic," it means that the environment lacks oxygen. This term is used
to describe processes or experiments occurring in the absence of oxygen
7. What are two industrial applications for fermentation?
Fermentation has various industrial applications, and two notable examples are:
Production of biofuels: Fermentation is used to convert biomass (such as corn or sugarcane) into
biofuels like ethanol, which can be used as an alternative to gasoline.
Food and beverage production: Fermentation is essential in making products like bread, yogurt, beer,
and cheese by utilizing microorganisms to transform raw materials.
This study source was downloaded by 1143875 from cliffsnotes.com on 08-10-2025 19:04:08 GMT -05:00
https://www.cliffsnotes.com//study-notes/3162431
, Anaerobic Fermentation
Part 2: Fermentation in Yeast
8. What is your hypothesis for this lab?
Carbon dioxide is produced when yeast ferments sucrose, there will be a noticeable shift in the amount
of air in the test tube. Compared to sucrose, artificial sweeteners like saccharin and stevia have a
reduced fermentability, thus when yeast interacts with them, the air space change will be modest. Since
yeast needs sugar to ferment, there won't be much of a change in the air space if it is exposed to warm
water without any sugar.
9. When yeast cells ferment, they split sugar into two products. What are those two products?
Ethanol and Carbon dioxide will be produced.
10. If fermentation is working, the little air space in the small test tube will start to grow and push the
yeast out into the larger test tube. What substance is in the growing air space?
If fermentation takes place, carbon dioxide will probably start to fill the expanding air space in the tiny
test tube. Given that it is a byproduct of yeast fermentation and that its creation causes the air space to
expand, the yeast mixture may be forced into the larger test tube.
Results
Table 1: Times at each interval for each experimental condition
Time Sugar Saccharin Stevia Water
Start time 3:30 3:35 3:40 3:45
15 minutes 5mm 0.5 mm 0 mm 0 mm
30 minutes 8.5 mm 1mm 0 mm 0 mm
Table 2: Air space size at each time interval, recorded in millimeters (mm)
This study source was downloaded by 1143875 from cliffsnotes.com on 08-10-2025 19:04:08 GMT -05:00
https://www.cliffsnotes.com//study-notes/3162431
