Fermentation Activity

Cellular Respiration

Process of using glucose to make ATP for the cell

Aerobic Respiration equation

6O₂ + C₆H₁₂O₆ → 6CO₂ + 6H₂O + 28-38 ATP

Three stages of Aerobic Respiration

1) Glycolysis (cytoplasm) 2) Citric Acid Cycle (mitochondria) 3) Electron Transport Chain (mitochondria)

Where does glycolysis occur?

Cytoplasm

Where does the citric acid cycle occur?

mitochondrial matrix

Where does the electron transport chain occur?

inner mitochondrial membrane(cristae)

Anaerobic Respiration

Fermentation without oxygen, produces 2 ATP

Alcoholic Fermentation equation

C₆H₁₂O₆ → 2CO₂ + 2C₂H₅OH + 2 ATP

Lactic Acid Fermentation equation

C₆H₁₂O₆ → 2C₃H₆O₃ + 2 ATP

Organisms performing Alcoholic Fermentation

Yeast and some bacteria

Organisms performing Lactic Acid Fermentation

Muscle cells, Lactobacillus

Lab 10.1 Purpose

Measure CO₂ production during fermentation with activators/inhibitors

Activators

increase the activity of enzymes

Inhibitors

Used to slow down a chemical reaction

Null Hypothesis (Ho)

No difference in CO₂ production across treatments

Alternative Hypothesis (Ha)

Difference in CO₂ production across treatments

Key Activators

Glucose, Magnesium Sulfate, Pyruvate

Key Inhibitor

Sodium Fluoride

Control Tubes (1,7)

No CO₂ produced (water only or missing components)

Highest CO₂ Production

Tube 3 (high activators), then 2,4,6

Lowest CO₂ Production

Tube 5 (high inhibitor/water)

Fermentation Location

Cytoplasm (not mitochondria)

CO₂ Measurement Method

Gas column height in inverted test tube after 45min incubation

Conclusion

Activators increase CO₂ production, inhibitors decrease it

Pyruvate Oxidation

Pyruvate reduced to CO₂+ethanol or lactic acid during fermentation

Rate of Fermentation

Directly proportional to CO₂ gas produced

Key purpose of Lab 10.1

To measure how activators/inhibitors affect CO₂ production in yeast fermentation

Independent variable

Chemical treatments (pyruvate, MgSO₄, NaF, glucose)

Dependent variable

Height of CO₂ gas column

Control groups

Tubes 1 & 7 (no yeast/only water)

Positive result indicator

Taller CO₂ gas column in fermentation tube

Main activators

Glucose (substrate), Pyruvate (metabolite), MgSO₄ (cofactor)

Main inhibitor

Sodium fluoride (blocks enolase in glycolysis)

Experimental setup

7 test tubes with inverted fermentation tubes

Incubation conditions

45 minutes at optimal yeast temperature

Tube with most CO₂

Tube 3 (rich in activators)

Tube with least CO₂

Tube 5 (high inhibitor concentration)

Key conclusion

Activators increase fermentation rate, inhibitors decrease it

Scientific principle shown

Enzyme activity affects metabolic pathways

Why CO₂ measured?

Gas production indicates fermentation rate

Critical control

Tube with just yeast+water (shows baseline activity)

Real-world application

Understanding metabolic regulation in brewing/baking

Common exam question

Predict CO₂ production if [X] inhibitor was added

Graph interpretation

Expect positive correlation between activators and CO₂ height

Test tube 1,7

Control (no co2 made)

Test tube 2,3,4, and 6

Had more activators than inhibitors (showed increase of co2 production)

Test tube 5

Had more inhibitor and/or water than activator (didn't make a lot of co2)