METABOLISM AND ENZYMES Mader Biology Chapter 6 METABOLISM
METABOLISM AND ENZYMES Mader Biology Chapter 6
METABOLISM
ATP is the cell’s source of energy
Reactions can be endergonic or exergonic Exergonic (exothermic) Endergonic (endothermic) Releases energy Absorbs energy ATP ADP + P ATP
Coupling ◦ Living systems couple endergonic with exergonic reactions
Kinetic Energy vs Chemical Energy Kinetic Energy of movement Chemical Energy stored in bonds
ENZYMES
Enzymes ◦ Functional proteins ◦ Used to catalyze chemical reactions ◦ They do this by decreasing the amount of activation energy needed for the reaction to occur
Anatomy of an Enzyme ◦ Substrate binds at the active site
Enzymes ◦ Don’t get changed or used up in the reaction ◦ Work on highly specific substrates ◦ Substrate attaches to Active Site with of the enzyme and is converted to product
Competitive vs. Non-competitive Inhibition COMPETITIVE INHIBITOR: NON-COMPETITIVE INHIBITOR: ◦ Takes the place of the normal substrate ◦ Attaches to the allosteric site (different than the active site) ◦ Does not change the ‘shape’ of the active site ◦ Usually reversible ◦ Changes the shape of the enzyme, and thereby the active site. ◦ Many are non reversible.
Factors affecting Enzymes ◦ Many will not work properly without Cofactors (inorganic- ex: Zn, Fe) or Coenzymes (organic). Most coenzymes are vitamins or vitamin derivatives ◦ Denaturation: ◦ p. H ◦ Temp ◦ Salinity
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