Cellular Respiration Chapter 9

Review  What is the equation for photosynthesis?  What are the two reactions for photosynthesis? Where do they occur?

Cellular Respiration  Location: Mitochondria (powerhouse of the cell)  Purpose: Turn chemical energy (food) into usable energy (ATP)  Chemical Equation: C 6 H 12 O O 2  6 CO H 2 O  Who needs this?: Eukaryotes

3 stages of Cellular Respiration in order  Glycolysis  Krebs Cycle  Electron Transport Chain

Glycolysis (stage one)  Means: Split glucose  Location: cytoplasm  Reactants (Input): Glucose  Products (Output): 2ATP and Pyruvates Note: pyruvates are often called pyruvic acid

Krebs or Citric Acid Cycle  Only occurs if oxygen is available (aerobic process)  Location: Mitochondria  Reactant: Pyruvate and oxygen  Product: 2ATP and CO 2

Electron Transport Chain  Location: Mitochondria  Reactant: Oxygen  Oxygen acts as an electron receptor.  Product: 32 ATP and H 2 O

Simplified Cellular Respiration Equation C 6 H 12 O O 2  6 CO H 2 O  How many ATP’s are created from one glucose molecule? 36  What is the relationship between photosynthesis and cellular respiration?

Relationship  Opposite processes

Relationship  Photosynthesis is about energy capture where cellular respiration is about energy release.  36% of energy from glucose is given off as ATP which leaves 64% given off as heat.

Review  What is the equation for cellular respiration?  What are the three reactions for cellular respiration? Where do they occur?  What are all the inputs for cellular respiration?  What are all the outputs for cellular respiration?  What is the relationship between photosynthesis and cellular respiration?

Fermentation

What is fermentation?  In the absence of oxygen there is no cellular respiration, fermentation occurs and small amounts of ATP (energy) will be created in order to keep the cell from dying.

Two kinds of fermentation  Lactic Acid Fermentation  Alcoholic Fermentation

Lactic Acid Fermentation  Produces lactic acid and 2 ATP  Example:  Muscle Cells: Fermentation occurs during heavy exercise  Bacteria: Some help to make yogurt and cheese

Alcoholic Fermentation  Produces alcohol, carbon dioxide, and 2 ATP  Example:  Bread/yeast: This process causes bread dough to rise and the carbon dioxide released causes the holes in bread.  This is how alcoholic beverages are created.

Energy/Exercise  Short, quick bursts of energy  Body uses ATP already in muscles as well as ATP made by lactic acid fermentation.  Once finished with exercise you “huff and puff” for several minutes to pay back the built up “oxygen- debt” and clear the lactic acid from the body.

Energy/Exercise  Longer exercises  Fermentation only makes enough energy to last 90 seconds  Exercise longer than this can only get the energy it needs from cellular respiration.  The body stores energy in the form of the carbohydrate glycogen. These glycogen stores are enough to last for 15 to 20 minutes of activity. After that, the body begins to break down other stored molecules, including fats, for energy. This is how animals can hibernate by living off of stored fats.

Review  When does fermentation occur?  What are the two types of fermentation?  For each type: What are the inputs? What are the outputs?