Metabolism
the totality of an organism’s chemical reactions
Catabolism
-Spontaneous process
-∆G<0
-Exergonic reaction
-Hydrolysis
-Breaking down larger molecules into smaller ones
Anabolism
-Non-spontaneous process
-∆G>0
-Endergonic process
-Dehydration
-Building up smaller molecules into larger ones
Free Energy (G)
Energy available to do work
∆G
G(final state) - G(initial state)
Energy Types
-Thermal
-Potential
-Kinetic
-Chemical
-Heat (Thermal in transfer)
Metabolic Pathway
begins with a specific molecule and end with product(s)
Law of Thermodynamics
1st- Energy is neither created nor destroyed (only transferred)
2nd- With every energy transfer, some is lost in the form of heat (every energy transfer increases entropy)
Energy may decrease in a system but…
the universe’s total entropy always increases
Entropy
a measure of randomness/disorder
Open Systems
energy and matter can be transferred between systems
Closed(Isolated) Systems
exchanges with organisms cannot occur
Are organisms open or closed systems?
open
ATP drives endergonic reactions by…
phosphorylation
Substrate
what an enzyme binds to
Active Site
region on enzymes where a substrate binds
Induced Fit
enzyme wraps around the substrate
The more Free Energy…
the greater the work capacity/instability
Activation Energy (Eᴀ)
initial energy needed to activate a reaction
Catalyst
lowers the Eᴀ(activation energy) needed for a reaction; speeds up the chemical reaction
Cofactors
nonprotein enzyme assisters
Coenzymes
organic cofactors
Energy Coupling
the use of an exergonic reaction to drive an endergonic one
Thermodynamic
the study of energy transformations
What can affect enzyme activity?
pH and temperature
Competitive Inhibitor
bind directly to the active site; compete with the substrate
Noncompetitive Inhibitor
bind to another part of the enzyme (NOT the active site); makes the enzyme change shape, which makes the active site less effective