Mitochondria
Cellular Respiration Glucose (C6H12O6) + 6O2 → Energy for ATP + H2O + CO2
ATP
Energy from Chemical bonds
Energy for ATP synthesis
Currency of Energy for cells
Triphosphate
Adenosine
Diphosphate
Adenosine
ATP
ADP
hydrolysis
Products: ADP + Phosphate + Energy
Phosphorylation of ADP resynthesizes ATP
ATP provides energy For metabolic reactions
Cell Respiration Regenerates ATP
Figure 4.8
Cell Respiration Anaerobic • No oxygen required • Yields little energy • Yields 2 ATP per glucose
Aerobic • Requires oxygen • Much greater energy yield • Up to 38 ATP per glucose
glycolysis Acetyl CoA synthesis Citric Acid Cycle Electron Transport Chain
Glycolysis • Series of 10 reactions • Breaks down glucose into 2 Pyruvic Acid molecules • Occurs in Cytoplasm of Cell • Anaerobic Reaction (no oxygen required) • Yields • 2 ATP (net gain) per glucose • 2 NADH molecule • 2 Pyruvic Acid molecules
• 2 Phosphates are added to end of glucose • Glucose is a 6-carbon sugar • Primes glucose for further reactions • Consumes
2 ATP
• 6-Carbon glucose is split into 2 3-carbon Pyruvic Acid molecules • Produces 4 ATP total • Produces 2 NADH molecules
+4 ATP produced - 2ATP consumed
•1
NADH
•2
FADH2 2 electrons attached to hydrogen
1. NAD+
+ 2H H+
2. FAD +
2H
2 electrons attached to NADH
NADH
FADH2
+ H+ 2 electrons attached to FADH2
NADH & FADH2 carry electrons to the electron transport chain
No oxygen to receive electrons from NADH
Without Oxygen, NADH donates its electrons to pyruvic acid This regenerates NAD+, which is used again for glycolysis Lactic Acid is formed as waste 2 electrons
Pyruvic Acid
+ NADH
Lactic Acid + NAD+
Once oxygen is available: Lactic Acid is converted back to glucose by the liver Anaerobic Respiration • Inefficient reaction; yields only 2 ATP • Consumes a great deal of glucose • Quick source of energy; for intense exercise