Cellular Respiration

ATP: adenosine triphosphate 3 phosphate groups Consists of: a) amino group = adenine b) sugar = ribose c) 3 phosphate groups

Energy is stored in the phosphate bonds Converting ATP to ADP releases energy Then the cell needs to “re- charge” its batteries by attaching phosphates to AMP & ADP to make ATP 1 phosphate 2 P 3 P

Formula for respiration: Reactants Products

Importance of respiration: Releases energy from breaking down food molecules Cells need Energy Occurs in mitochondria Occurs in the presence of oxygen

1. Glycolysis: means “sugar-breaking” Glucose is broken into 2 molecules of pyruvic acid (since glucose is 6 carbons, pyruvic acid has 3 carbons)

1. Glycolysis: means “sugar-breaking” Occurs in the cytoplasm Uses energy (2 ATPs) Produces a net gain of 2 ATPs Produces 2 pairs of high energy electrons Passed from NAD+  NADH

Overall Flow Chart 1. Glycolysis Krebs Cycle Fermentation No Oxygen Glycolysis Oxygen 2a. 2b. Krebs Cycle Fermentation 3. Electron Transport

2a. Fermentation: occurs ONLY in cells that lack oxygen Lactic Acid Fermentation Alcoholic Fermentation

a) Lactic acid fermentation: Produced in cells after glycolysis has occurred ONLY when there is NO oxygen present Occurs in muscles during vigorous exercise  muscles burn/sore

b) Alcoholic Fermentation After glycolysis when NO oxygen is present, pyruvic acid is broken down to produce alcohol and carbon dioxide instead of lactic acid. Occurs in yeast and causes bread dough to rise

2b. Krebs Cycle Chemical bonds in pyruvic acid are broken apart in the mitochondria Also called “citric acid cycle” Releases CO2 that you then exhale in your breath The electron carriers are NAD+ and FAD+

3. Electron Transport Chain (Occurs across membranes of mitochondria) The transfer of electrons is used to produce ATP from ADP  Electron carriers are NADH and FADH2  Oxygen is used to accept electrons to form H2O  This is why we need oxygen!

Cellular respiration occurs in BOTH plant AND animal cells *** Cellular respiration occurs in BOTH plant AND animal cells!!!! *** (This is different from external respiration – the inhalation and exhalation of air)

Total Breakdown of Glucose 2 ATP Glucose Occurs In Cytoplasm Glycolysis Glucose Pyruvic Acid

Total Breakdown of Glucose Krebs Cycle 2 ATP Occurs In Mitochondria Glucose Pyruvic Acid 32 ATP Total 36 ATP