Cell Respiration

Consumers/ Heterotrophs• Autotrophs use sunlight to make ATP and Glucose• Heterotrophs – get glucose from eating other

organisms and using it to make ATP.

Cell Respiration• Cell Respiration-process by which the mitochondria break down

glucose to make ATP. (produces 36-38 ATP’s)• Opposite of photosynthesis (ATP to Glucose)

Reaction

• 6 O2 + C6H12O6 6 H2O + 6 CO2 + ATP

• Occurs in 3 Stages

e-e-

Mitochondria• Stage 1 in the cytoplasm

• Stage 2 in the matrix

• Stage 3 in the inner membrane

cytoplasm

Glycolysis (stage 1)All glucose molecules first go through glycolysis– Anaerobic- no oxygen needed– Occurs in the cytoplasm– Produces: -2 net ATP molecules -2 NADH molecules(electron carrier) -2 Pyruvic Acid molecules-Hydrogen is released

Glycolysis

1 Molecule of Glucose

2 Molecules of G3P

2 Molecules of Pyruvate*

Gained 2 net ATP’sGained 2 NADH’sHydrogen is released

Citric Acid Cycle/ Krebs Cycle-stage 2- Aerobic- requires oxygen-occurs in the mitochondrial matrix-a 3 carbon Pyruvate is converted into a molecule of 2

carbon acetyl-CoA.(CO2 is released)- This happens twice because there are two Pyruvates- 2 NADH’s are made

CoA = co-enzyme A

Citric Acid Cycle cont’d-two Acetyl-CoA’s go through the citric acid cycle

- CO2 is released

- 6 molecules of NADH are

made

-2 molecule of FADH2 (e- carrier)

are made

-Yields 2 molecules of ATP

Hydrogen is released*

Electron Transport ChainStage 3, Oxidative Phosphorylation-Aerobic- requires oxygen-occurs in inner membrane.-NADH delivers e-’s to the first protein in the ETC

-FADH2 delivers e-’s to the second protein in the ETC.

ETC Cont’d• Each NADH yields about 3 ATP’s (give or take)

• Each FADH2 yields about 2 ATP’s (give or take)

• As electrons flow down the chain they cause Hydrogens to get sucked out of the mitochondrial matrix into the inner membrane space.

ETC Cont’d• As the concentration of H+’s build up they are sucked

back into the mitochondrial matrix through ATP synthase

• Oxygen is the final e- acceptor, it bonds with H+ to make water (which is released)

• 32-34 ATP’s are produced*

Final ATP Count

Photosynthesis vs. Respiration

Fermentation• Fermentation - anaerobic ATP production that occurs after

glycolosis when oxygen is not available. (not efficient , 2 ATP’s)• Two Types

Lactic Acid Fermentation• Lactic Acid Fermentation- produces 2 ATP’s and lactic

acid (lactate). The lactic acid is stored in muscles and turned into pyruvate. (ex. when exercising)

Alcoholic Fermentation• Alcoholic Fermentation- produces 2 ATP’s, CO2, and

ethyl alcohol. (ex. yeast)

Glucose

Glycolysis

no oxygen oxygen

AnaerobicFermentation

Aerobic Respiration

Lactic Acid Fermentation

Alcoholic Fermentation

Electron Transport Chain

Kreb’s Cycle (Citric Acid Cycle)

32 ATP’s

2 ATP’s

2 ATP’s

2 ATP’s

2 ATP’s

You should now be able to:1. Explain in general terms how redox reactions

are involved in energy exchanges

2. Name the three stages of cellular respiration; for each, state the region of the eukaryotic cell where it occurs and the products that result

3. In general terms, explain the role of the electron transport chain in cellular respiration

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4. Explain where and how the respiratory electron transport chain creates a proton gradient

5. Distinguish between fermentation and anaerobic respiration

6. Compare and contrast respiration and photosynthesis in terms of location, reactants, products, what is oxidized, what is reduced.

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings