Energy - Catabolic and Anabolic Pathways

• Energy is the ability to do work– The ability to do that work depends on catabolic process that

harvest the chemical potential energy found in organic molecules. • 2 basic strategies for harvesting energy

– Autotrophy– Heterotrophy

Autotrophs• Are organisms that produce energy from

inorganic compounds and fix (PLACE) it into organic compounds for later use.– Photoautotrophs (plants, algae, some

protists and bacteria)• Convert the sun’s energy into sugar through

photosynthesis

– Chemoautotrophs• Some bacteria use inorganic compounds to fix

energy– Methanogens use the energy found in methane

molecules

Heterotrophs

• Are organisms that consume organic compounds created by autotrophs to convert into the energy containing compound ATP– Although there are different strategies (herbivore,

carnivore, & omnivore) ALL energy consumed originally came from the sun.

Production of ATP– ATP is produced in the mitochondria yielding 32

to 38ATP per molecule of glucose from existing ADP & inorganic phosphate (Pi) in the body

– The chemical energy stored in the ATP can be later used by the body to power the reactions needed for survival» Growth, repair, energy production, reproduction, …

ATP = Energy• ATP is the primary molecule used in the

catabolic pathway to produce energy to power metabolic processes– ATP g ADP + Pi + energy