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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


Section 2, Chapter 4 Metabolism