5.2: Cellular Respiration (Aerobic Respiration)

 Plants—make food (sugar) through photosynthesis  Animals and other organisms—get food by eating plants and animals Energy Review

 Cellular respiration— glucose and food are broken down to make energy (ATP) in ALL organisms  Occurs in the mitochondria of eukaryotes  Occurs in the cytoplasm of prokaryotes Cellular Respiration

C 6 H 12 O 6 + O 2 CO 2 + H 2 O + energy C 6 H 12 O 6 + O 2 CO 2 + H 2 O + energy Cellular Respiration Equation

 Aerobic Respiration: breaking down of glucose molecules into smaller pieces in the presence of oxygen to produce ATP Cellular Respiration

 THREE STEPS OF AEROBIC RESPIRATION 1. Glycolysis 2. Kreb’s/Citric Acid Cycle 3. Electron Transport Chain (ETC) Cellular Respiration

1. Glycolysis: occurs in cytoplasm; glucose is split in half, forming a pyruvate molecule  2 ATP released  Electrons released and carried to mitochondria Cellular Respiration

Glycolysis quiz  Where does glycolysis take place?  What molecule is used in glycolysis?  What are the products of glycolysis?  What ultimately happens to each of these products?  Write an equation that represents glycolysis

2. Kreb’s/Citric Acid Cycle: occurs in the mitochondria; pyruvate is split into smaller pieces  CO2 gas released (we breathe it out)  2 ATP released  Electrons released and move to mitochondria Cellular Respiration

Krebs/Citric Acid Cycle Quiz  Where does the CAC occur?  What molecule is used in the CAC?  What are the products of the CAC?  What happens to each of these products?  Write an equation that represents the CAC

3. Electron Transport Chain (ETC): made of proteins in the mitochondrial membrane  Electrons dropped off at proteins  Electrons lose energy as get passed from protein to protein  Energy lost from electrons is used to make ATP  32 ATP made  Electrons finally passed to OXYGEN to make WATER Cellular Respiration

Mitchondrial Membrane ETC Proteins e- H2OH2O O2O2

TOTAL ENERGY: 36 ATP from 1 glucose Cellular Respiration

ETC quiz  What is the ETC?  What happens as the electrons get passed from protein to protein down the ETC?  What happens to the extra energy?  What happens to the electrons at the end of the ETC? CR Animation

Glycolysis Krebs Cycle (CAC) ETC Glucose Pyruvate Electrons CO 2 ATP O2O2 Electrons ATP H2OH2O

Cellular Respiration (Anaerobic Respiration)

 Anaerobic Respiration: breaking down glucose molecules into smaller pieces the ABSENCE of oxygen to produce ATP Cellular Respiration

 TWO STEPS OF ANAEROBIC RESPIRATION 1. Glycolysis: occurs in cytoplasm; glucose is split in half, forming a pyruvate molecule  2 ATP released  Electrons released and carried to mitochondria Cellular Respiration

 TWO STEPS OF ANAEROBIC RESPIRATION  2. Fermentation: breaking down pyruvate without oxygen Cellular Respiration

 Lactic acid fermentation: pyruvate is broken down to make lactic acid + ATP  2 ATP released  Lactic acid builds up as in muscle cells & causes burning sensation (muscle cramping) during strenuous exercises C-C-C +  H-C-C-+ ATP pyruvate  lactic acid energy Cellular Respiration

 Alcoholic fermentation: pyruvate is broken down into alcohol, carbon dioxide, and ATP in yeast and bacterial cells  2 ATP released  Used in making bread and alcohol beer C-C-C  C-C-OH + CO2 + ATP Pyruvate  alcohol + carbon + energy dioxide dioxide Cellular Respiration

Eat DigestionGlycolysis Citric acid cycle Electron transport chain Oxygen is present No oxygen is present Fermentation (anaerobic respiration) Lactic acid fermentation Alcoholic fermentation In animals In yeast Aerobic respiration Cellular Respiration

___________________________ _________ ____________ __________ __________ __________ _____________________ ____________________ ________ _______ _________ Cellular Respiration

Photosynthesis vs.Respiration food synthesized food broken down requires energyproduces energy Chloroplastmitochondria/cytoplasm Only autotrophs Autotrophs and heterotrophs (all living cells)