How Cells Harvest Chemical Energy

1
Chapter 6 How Cells Harvest Chemical Energy
2
What we (should) already know!
3
Cellular Respiration
4
How much energy is needed by our body?
5
(No Transcript)
6
Oxidation-Reduction Reactions (Redox)

• Occurs when electrons are moved from one molecule
  to another
• The molecule that loses the electron(s) is
  OXIDIZED (called oxidation)
• The molecule that gains the electron(s) is
  REDUCED (called reductions)
• They will always go together
• As electrons move, they lose potential energy

7
Redox in Cellular Respiration
8
Two key players in the oxidation of glucose

• Dehydrogenase removes hydrogen from glucose
• NAD coenzyme that picks up the electrons and
  carries them to oxygen (also a sister coenzyme
  called FAD)

9
Energy Staircase
10
Cellular Respiration 3 main stages

• Glycolysis
• Citric Acid Cycle
• Oxidative Phosphorylation

11
Glycolysis Overview

• Takes place in the cytoplasm
• Converts glucose into pyruvate
• Other important products are some NADH and some
  ATP

12
(No Transcript)
13
Citric Acid Cycle Overview

• Takes place in the mitochondrial matrix
• Converts pyruvate into CO2
• Other important products are LOTS of NADH (and
  FADH2) and some ATP

14
(No Transcript)
15
Oxidative Phosphorylation Overview

• Takes place across the inner mitochondrial
  membrane
• Uses the electrons picked up by NAD and FAD to
  create a hydrogen gradient across the membrane
• As the hydrogens diffuse across the membrane to
  reset equilibrium (chemiosmosis), ATP is produced
  (using ATP synthase)

16
(No Transcript)
17
Oxidative vs. Substrate Level Phosphorylation

• Substrate Level an enzyme transfers phosphate
  group from a substrate molecule directly to ADP
• Oxidative Phosphorylation energy released from
  redox reactions is used to phosphorylate ATP

18
Glycolysis In Depth
19
Glycolysis Energy Investment
Glycolysis Energy Payoff
20
Glycolysis Energy Payoff
21
Pyruvate gets groomed
22
(No Transcript)
23
Oxidative Phosphorylation
24
ATP
25
(No Transcript)
26
Lactic Acid Fermentation
27
Alcohol Fermentation
28
Energy Production Summary
Glucose
GLYCOLYSIS
NADH
Pyruvate
FADH2
CO2
Acetyl CoA
OXIDATIVE PHOSPHORYLATION
CITRIC ACID CYCLE
CO2
H2O
29
Energy Production Summary
Glucose
GLYCOLYSIS
NADH
Pyruvate
Lactic Acid OR Ethanol
30
(No Transcript)