BIOL 2051 Chapter : Chapters 13 And 14
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Chapter 13.3-13.7 Energetics & Catabolism
Chapter 14 Respiration, Lithotrophy, & Photolysis
Metabolism
• Catabolism
– Breaking down molecules for energy
– Catabolic pathways breakdown large molecules in a series of steps coupled to
reactions that store energy in small carriers such as ATP and NADH
• Anabolism
– Using energy to build cell components
• Metabolism
– Balance between catabolism and anabolism
– Central biochemical pathways used for both (amphibolic)
• TCA cycle, glycolysis, pentose phosphate shunt
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Metabolism
Sunlight
Reduced geological
compounds (rocks,
inorganic compounds)
(Reduced) biological
macromolecules
(starch, fats)
(First energy
source)
(Major energy
source today) (Energy source
for animals)
Energy
CATABOLISM
Phototrophy Lithotrophy Organotrophy
ATP
Short-term
energystorage
ANABOLISM
Carbon,
nitrogen,
water
Long-term
energy storage
Biosynthesis
Catalysis and Enzymes
• Activation energy
o Energy required to bring all molecules in a chemical reaction into the reactive state
• Enzymes
o Catalytic proteins
o Speed up biochemical reaction rates
o Lower activation energy by bringing substrates into proximity to each other and
correctly orienting them
• Active/catalytic site
o Portion of an enzyme to which substrate binds.
• Substrate ------------------→ product(s)
aldolase enzyme:
Fructose-1,6-bisphosphate → glyceraldehyde-3- phosphate + dihydroxyacetone phosphate
• Very specific for their substrate
– Cellulose vs. starch example
• Enzymes can have small non-protein components that help in catalysis but aren’t a part of
the enzyme or substrate
o Prosthetic groups - bound tightly to their enzyme, usually covalently or permanently
⎯ Example- heme group in cytochromes
Document Summary
Catabolic pathways breakdown large molecules in a series of steps coupled to reactions that store energy in small carriers such as atp and nadh: anabolism, metabolism. Central biochemical pathways used for both (amphibolic: tca cycle, glycolysis, pentose phosphate shunt. Reduced geological compounds (rocks, inorganic compounds) (reduced) biological macromolecules (starch, fats) (energy source for animals) (first energy source) Fructose-1,6-bisphosphate glyceraldehyde-3- phosphate + dihydroxyacetone phosphate aldolase enzyme: very specific for their substrate. Cellulose vs. starch example: enzymes can have small non-protein components that help in catalysis but aren"t a part of the enzyme or substrate, prosthetic groups - bound tightly to their enzyme, usually covalently or permanently. Example- heme group in cytochromes: coenzymes - loosely bound to their enzyme, may associate with different enxymes, Example- nad+, derivative of niacin: enzymes are named either for the substrate they bind or for the chemical reaction they catalyze with the addition of the suffix -ase, for example.
