O 2 + C 6 H 12 O 6  CO 2 + H 2 O + 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) 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

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 + + CO 2 + 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/Homework 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 NADP + ? 6.How are lactic acid fermentation and alcoholic fermentation different? How are they similar?