Cellular Respiration

2

• Hypothesize why there are more mitochondria in people with Luft syndrome. Explain your reasoning.

Aerobic Cellular Respiration• extracts energy from food in the presence of oxygen

• energy is used to synthesize ATP from ADP and Pi

• eukaryotes & prokaryotes that are obligate aerobes undergo Cellular respiration

The Overall Equation

5

Note the outline of the mitochondria in the background of the figure of the next slide…

1. Which step of cellular respiration takes place outside of the mitochondria?

2. Check your diagram and label of the mitochondria with the one found on slide 8.

Cellular Respiration

“The Powerhouse”

Aerobic Cellular Respiration4 stages: 1. Glycolysis 2. Pyruvate oxidation (Transition stage) 3. Citric acid cycle 4. Electron transport Chain & oxidative

phosphorylation

9

Note the graphic on the next slide and consider:

• What happens to all of the carbon molecules in sugar?

• At what stage of Cellular Respiration is most of the ATP made?

• Note how many carbon dioxide and water molecules are created and how many oxygen molecules are required. How do these numbers relate to the chemical equation?

6 Carbons Glucose sugar

C

C

C

C

C

C

C

C

C

C

C

C2 ATP

GlycolysisElectron

Transport Chain

32 ATP

6O2

6H2O

C

C

C

CPyruvate oxidation

CO2C2

Citric Acid Cycle

2 ATP

CO2C4

Overall view of C.R.

12

• Make note of where each stage of CR takes place. You may want to add that information to your diagram of the mitochondria.

1. Glycolysis• takes place in cytoplasm • enzymes break down one molecule of glucose into

two molecules of pyruvate • some ATP and NADH are produced

2. Pyruvate Oxidation (transition stage)

• occurs in the mitochondria • pyruvate is transported (via carrier protein) into

mitochondria and is oxidized, forming acetyl-CoA • CO2 and NADH are produced

3. Citric Acid (Krebs) Cycle• takes place in mitochondria • acetyl-CoA enters a cycle and is completely

oxidized to CO2

• ATP, NADH and FADH2 are produced

4. Electron Transport…• takes place in mitochondria • the NADH and FADH2 from the first 3 stages are

oxidized • H2O and a large amount of ATP is produced (32-34)

1. Substrate-level phosphorylation - catalyzed by a kinase - phosphate is transferred directly from a substrate

ATP can be produced in two ways:

2. Oxidative phosphorylation - catalyzed by ATP synthase - process uses energy transferred indirectly from a series of

redox reactions

What if there is no O2?• many organisms can extract energy from food

without using oxygen using anaerobic respiration and fermentation

• much lower amount of energy release in anaerobic pathways

Anaerobic Respiration

We know what obligate aerobes are… What about… • obligate anaerobes? • facultative anaerobes?

22

• Write a three sentence summary of Cellular Respiration.