Transcript Energy metabolism - Donald Edward Winslow

Energy metabolism
Introductory Biology, 9 September 2010
Donald Winslow
References:
Alberts et al. 2008. Molecular Biology of the Cell,
5th ed., Garland Science, NY; Ch. 2, Ch. 14.
Hoefnagels 2009. Biology, 1st ed., McGraw-Hill,
NY; Ch. 4 (pp 80-89), Ch. 5 (pp 102-106, 108110), Ch. 6 (pp 120-126).
Conservation laws
& thermodynamics
Conservation of matter
Conservation of energy
(1st law of thermodynamics)
Different forms of energy
Kinetic energy
Potential energy
Heat
Electromagnetic radiation
etc.
2nd law of thermodynamics
2nd Law of Thermodynamics
Entropy increases in closed systems.
Entropy is disorder.
A closed system does not exchange energy or matter
with anything outside it.
Transition of energy from one form to another
always results in a loss of useful energy.
Automobile engine
Incandescent light bulb
Objectives
Describe how photoautotrophs use solar radiation
to build organic molecules that store energy.
Explain how respiration and photosynthesis relate
to each other in terms of reactants, products,
and energy flow.
Describe a metabolic cascade, such as glycolysis,
and explain the roles of specific enzymes.
Explain the citric acid cycle, electron transport,
and oxidative phosphorylation.
Explain the roles of ATP, NADH, and NADPH.
Metabolism

Catabolism
–
Cellular respiration
6O2 + C6H12O6 --> 6CO2 + 6H2O + metabolic energy

Anabolism
–
Photosynthesis
6CO2 + 6H2O + solar radiation --> 6O2 + C6H12O6
Cellular respiration
Glycolysis
Citric acid cycle
Electron transport chain
Chemiosmotic phosphorylation
Glycolysis (a metabolic cascade)
Glucose --> Glucose-6-Phosphate
G6P --> Fructose-6-Phosphate
F6P --> Fructose-1,6-Bisphosphate
F16B --> Phosphoglyceraldehyde
PGAL --> 1,3-Bisphosphoglycerate
13BG --> Phosphoglycerate
PG --> Phosphoenolpyruvate
PEP --> Pyruvate
Cellular respiration

Glycolysis & fermentation

Citric Acid Cycle

Respiratory Electron Transport Chain
Mitochondria

Aligned along microtubules

Outer membrane, inner membrane

Matrix, intermembrane space, cristae

Respiratory electron-transport chain
Photoautotrophs
Plants
Algae
Cyanobacteria
Goat’s Rue in Door County, Wisconsin
Photosynthesis