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Cellular Respiration Part 2 Glycolysis - Pages 93 to 95

Cellular Respiration Part 2 Glycolysis - Pages 93 to 95

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Page 1: Cellular Respiration Part 2 Glycolysis - Pages 93 to 95

Cellular Respiration Part 2Glycolysis - Pages 93 to 95

Page 2: Cellular Respiration Part 2 Glycolysis - Pages 93 to 95

Overview: Cellular Respiration

•Cellular Respiration takes place in three steps:▫Glycolysis – initial breakdown of glucose;

very little direct energy production; takes place in cytoplasm

▫Krebs Cycle – finishes the breakdown of glucose; very little direct energy production; takes place in the matrix of the mitochondria

▫Oxidative Phosphorylation – major energy producing process; takes place in the cristea of the mitochondria

Page 3: Cellular Respiration Part 2 Glycolysis - Pages 93 to 95

Fig. 9-6-3

Mitochondrion

Substrate-levelphosphorylatio

n

ATP

Cytosol

Glucose Pyruvate

Glycolysis

Electronscarried

via NADH

Substrate-levelphosphorylatio

n

ATP

Electrons carried

via NADH andFADH2

Oxidativephosphorylatio

n

ATP

Citric

acidcycle

Oxidativephosphorylation

:electron transport

andchemiosmosis

Page 4: Cellular Respiration Part 2 Glycolysis - Pages 93 to 95

Glycolysis

•Glycolysis (“splitting of sugar”) breaks down glucose into two molecules of pyruvate

•Glycolysis occurs in the cytoplasm and has two major phases:▫Energy investment phase▫Energy payoff phase

Page 5: Cellular Respiration Part 2 Glycolysis - Pages 93 to 95

Fig. 9-8

Energy investment phase

Glucose

2 ADP + 2

P 2 ATP used

formed

4 ATP

Energy payoff phase

4 ADP + 4 P

2 NAD+ + 4 e– + 4 H+

2 NADH

2 Pyruvate

2 Pyruvate GlucoseNet

4 ATP formed – 2 ATP used

2 ATP

2 NAD+ + 4 e– + 4 H+

2 NADH + 2 H+

Page 6: Cellular Respiration Part 2 Glycolysis - Pages 93 to 95

Glycolysis

•Takes place in the cytoplasm

•Believed to be the oldest metabolic process – shared by all organism

•ATP produced during the process via substrate level phosphorylation

Page 7: Cellular Respiration Part 2 Glycolysis - Pages 93 to 95
Page 8: Cellular Respiration Part 2 Glycolysis - Pages 93 to 95

Glycolysis – summarized in words• 2 molecules of ATP are used to start the process –

phosphorylating (energizing) the 6 carbon molecule– unstable 6C

• Unstable 6 C splits into to 3 C called G3P

• Oxidation of 2-3C (G3P) and reduction of 2 NAD+ to 2NADH releases enough energy to phosphorylate the 3C molecule

• Phosphates removed from 2-3C molecules in substrate level phosphorylation to produce 4 ATP; end with pyruvate

Page 9: Cellular Respiration Part 2 Glycolysis - Pages 93 to 95

Glycolysis Summary• Reactants

▫Glucose, 2ATP and 2NAD+• Products

▫Pyruvate, 4 ATP, and 2 NADH• Net gain of ATP

▫2 ATP• Do you need to know all of the intermediates

in the process?▫NO – understand that it occurs in several steps,

each step involves different enzymes & results in a different carbon compound