Cellular Respiration

1
Cellular Respiration

• Chapter 9

2
Cellular Respiration

• Process by which mitochondria break down food
  molecules to make ATP
• C6H12O6 O2 ? CO2 H2O Energy
• Three Stages
• Glycolysis
• Citric Acid Cycle (Krebs Cycle)
• Electron Transport Chain

3
(No Transcript)
4
Anaerobic vs. Aerobic

• Anaerobic
• Without oxygen
• Glycolysis, Fermentation
• Obligate Anaerobe
• Cannot survive in the presence of oxygen
• Tetanus
• Facultative Anaerobe
• Can use oxygen, but can survive in its absence
• Yeast

• Aerobic
• Uses Oxygen
• Krebs and e- transport chain
• Produces a lot more energy

5
Glycolysis

• Occurs in the cytoplasm of the cell
• Breaks down glucose ( 6-Carbon) into 2 pyruvic
  acid (3-Carbon)
• Makes 4 ATP, but uses 2 ATP 2 ATP
• NAD accepts electrons to become NADH
• Those e- move to the e- transport chain

Summary Glycolysis makes 2 ATP, NADH, and 2
pyruvic acid.
6
Citric Acid Cycle

• Begins after pyruvic acid is transformed into
  acetyl-CoA (this rxn also makes NADH)
• Occurs in the matrix of the mitochondria
• For every turn of the cycle the following are
  made
• 1 ATP
• 2 CO2
• 3 NADH
• 1 FADH2
• This cycle happens twice for each glucose

7
Electron Transport Chain

• Located in the inner membrane of the mitochondria
• Similar to the e- transport chain in
  photosynthesis
• NADH and FADH2 supply the energized e-
• ATP is produced and H is pumped into the matrix
  of the mitochondria
• As the ATP moves out of the mitochondria more ATP
  is made
• Oxygen is the final e- acceptor at the end of the
  chain results in the formation of water
• Makes 32 ATP

8
(No Transcript)
9
Summary of Cellular Respiration
ATP NADH FADH2 Other Products
Glycolysis 2 net (4 total) 2 Pyruvate
Pyruvic acid to Acetyl-CoA 2 CO2 Acetyl-CoA
Krebs (In 2 turns) 2 6 2 CO2
Electron Transport Chain 32 H2O
10
The 36 ATP produced in cellular respiration
represent only about 38 of the energy stored in
the sugar the rest of the energy is released as
heat
11
What if no oxygen is available?

• Glycolysis will continue, but if NAD is not
  recycled it will stop, too.
• Less energy is produced only 2 ATP
• Fermentation cycles the NAD back to glycolysis,
  but does not produce energy

12
Fermentation

• Lactic Acid Fermentation
• Makes lactic acid, CO2, and NAD
• Occurs in muscles when an oxygen debt is created

• Alcoholic Fermentation
• Makes alcohol, CO2, and NAD
• Yeast and some bacteria