Cellular Respiration

ENERGY!!! You have got to get energy From what? Most of you eat to get energy – correct? What is in food to give you energy? The answer: GLUCOSE Wait, sugar only gives you a burst of energy, not full time energy. AHHH, but you convert it to something that sustains you. What’s that?

ATP ATP – Adenosine Triphosphate

Where does this happen? ATP is generated in your mitochondria of your cells You have more mitochondria in muscle cells than other organelles

Cellular Respiration Cellular Respiration – process that releases energy from food in the presence of oxygen It happens from the following chemical equation: Oxygen + Glucose  Carbon dioxide + Water + ENERGY 6O 2 + C 6 H 12 O 6 --> 6CO 2 + 6H 2 O + ATP

How does it happen? You undergo the process of cellular respiration by three steps. A. Glycolysis B. Krebs Cycle C. Electron Transport Chain But you start it all, by taking a breath of oxygen…

Glycolysis In Glycolysis 1 molecule of glucose is broken down into 2 molecules of pyruvic acid This releases about 10% of the energy found in glucose This is splitting the sugar into 2 separate 3 Carbon compounds It produces about 2 ATP It also gives 4 electrons to NAD+

Krebs Cycle Krebs Cycle – pyruvic acid is broken down into carbon dioxide in a series of energy extracting reactions Acetic acid is made first. The carbons rearrange to form acetyl-CoA. As Krebs continues, a 6 carbon molecule of citric acid is made 2 ATP are also made NAD +  NADH and FAD  FADH 2

Electron Transport Chain The high energy electrons from glycolysis and Krebs cycle is used to convert ADP (adensosine diphosphate) to ATP NADH and FADH 2 pass their high energy electrons to the electron transport chain. Each time they do this, 3 molecules of ATP are generated All in all with all the molecules in glucose, 32 molecules of glucose are made

How much ATP is produced? Glycolysis, Krebs Cycle and Electron Transport Chain all produce 36 molecules of ATP for every molecule of glucose used by them MORE energy than that produced by an automobile or burning gasoline 36% of you creates energy using food you eat. The other 64% of food is converted to heat to keep you at an even 37 C

Aerobic Respiration VS. Anaerobic Respiration All of this ATP is created by aerobic respiration Aerobic Respiration – in the presence of oxygen Anaerobic Respiration – respiration without the use of oxygen It happens sometimes when expected or unexpected (in you)

Fermentation Fermentation – cellular respiration that occurs in the absence of oxygen Two kinds are available: A. Alcoholic Fermentation – used by yeast and also to make alcoholic beverages B. Lactic Acid Fermentation – used by bacteria to make cheese, yogurt, buttermilk, sour cream, pickles, sauerkraut and kimchi