Fermentation - Marblehead High School

O2 + C6H12O6  CO2 + H2O + ATP
What is it?
• The chemical pathway that provides living
organisms with energy by breaking down
• The process releases the energy from the
foods you eat or the calories you intake
calorie – the amount of energy needed to
raise the temperature of 1 gram of water 1
degree Celsius
Food labels - kilocalories (C)
1000 calories
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Three Main Steps:
1) Glycolysis
If oxygen is
2) Krebs Cycle
3) The Electron
Transport Chain
The “powerhouse” of the Cell
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
What is Glycolysis?
• The process that breaks glucose (6 carbon
sugar) apart into two 3 carbon sugars
called pyruvic acid
• It requires 2 ATP from the cell to start
• It produces 4 ATP and the electron carrier,
• Outcome: 2 ATP + 2 NADH molecules
NAD+ + 2e-  NADH
What was an electron carrier?
• NADPH in photosynthesis was used to
carry energy to the Calvin cycle
• NADH holds high energy electrons in
order to carry their energy to the Electron
transfer chain in respiration
A closer look at glycolysis…
• Where do you think it
• Does it require
oxygen to take place?
• It occurs quickly
• Does it generate a lot
of cell energy? How
• What happens next?
If no oxygen is present…
Fermentation – a method used to generate
energy for the cell even when no oxygen is
What does it need to do?
- Regenerate NAD+ so it can pick up more
electrons during glycolysis and continue
ATP production
This is why
NAD+ must be
regenerated in
order for
glycolysis to
Two Types of Fermentation:
1) Alcoholic Fermentation
Pyruvic acid + NADH  NAD+ + CO2 + alcohol
Occurs in yeast; used for bread rising (forming air
spaces in bread) and alcoholic beverage
Two Types of Fermentation
2) Lactic Acid fermentation
Pyruvic acid + NADH  lactic acid + NAD+
Occurs during strenuous exercise when you can’t
get enough oxygen to your muscles; causes
burning feeling in muscles
Occurs in bacterial cells during cheese, yogurt and
sour cream production
First, complete the Glycolysis and
Fermentation worksheet and then,
9-1 Section Assessment page 225, #1-6
1. Describe the process of cellular respiration
2. What are the products of glycolysis?
3. Name the two main types of fermentation.
4. What is a calorie? Calorie?
5. How is the function of NAD+ similar to that of
6. How are lactic acid fermentation and alcoholic
fermentation different? How are they similar?