O2 + C6H12O6 CO2 + H2O + ATP

What is it?

• The chemical pathway that provides living organisms with energy by breaking down foods

• 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)

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Kilocalorie

1000 calories

Three Main Steps:

1) Glycolysis

2) Krebs Cycle

3) The Electron Transport Chain

If oxygen is available

The “powerhouse” of the Cell

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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,

NADH• 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 occurs?

• Does it require oxygen to take place?

• It occurs quickly • Does it generate a lot

of cell energy? How much?

• What happens next?

If no oxygen is present…

Fermentation – a method used to generate energy for the cell even when no oxygen is available

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 occur

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 production

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

Classwork/HomeworkFirst, complete the Glycolysis and

Fermentation worksheet and then,9-1 Section Assessment page 225, #1-61. Describe the process of cellular respiration2. 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

NADP+?6. How are lactic acid fermentation and alcoholic

fermentation different? How are they similar?