Enzymes | AP Bio

Endergonic Reaction

• Products have more energy than reactants

• Requires energy input

• Not spontaneous

• ΔG is Positive

Exergonic Reaction

• IS spontaneous

• Products have less energy than reactant

• ΔG is negative

ΔG

• Change in energy

• Amount of energy to get reaction started

• Makes/breaks bond

To solve for ΔG

Product minus reactant

How to solve for activation energy

Activation complex minus reactant

Activtion energy

Energy required to start a chemical reaction

Catalyst (Enzyme)

Lowers amount of activation energy & speeds up chemical reaction

• Creates same amount of product but faster

Substrate Specificity

• Only one certain substrate the enzyme accepts

• Induced fit (snug fit)

Increasing rate of reaction will _____ rate of substance

Increase

Increasing rate of reaction will _____ rate of enzyme

Increase

Increasing rate of reaction will _____ rate of product

Decrease

When substrate fits into the enzyme…

It breaks the bond and creates a product

• If it doesn’t fit perfectly, it doesn’t get broken down

Competitive Inhibitor

Interacts with active site of enzyme so substrate can’t bind

• SOME product is produced

Allosteric Inhibitor (Non competitive)

Changes shape of enzyme so it can’t bind to substrate

• No product is produced

Cofactors

• Nonprotein inorganic compound/ion

• Bound within enzyme molecules

• Mg, K, Ca, Zn, Fe, Cu

Coenzyme

Nonprotein organic molecule

Anabolic (metabolic pathways)

Expend energy to make bonds

Catabolic (metabolic pathways)

Harvests energy by breaking (cutting) bond

Feedback Inhibition

• Enzyme gets shut down (a lot of final product) & starts again (when there’s not enough final product)

Affecting an enzymes Temperature affects chemical reaction

Above: Denatures structure → nothing is produced → lowest rate of reaction

Optimal: Perfect Structure → highest amount product produced → highest rate of reaction

Below: NOT denatured → low amount of product produced → lowest rate of reaction & low kinetic energy

Affecting an enzymes pH affects chemical reaction (H+ & OH- ions)

Above: Denatured structure → nothing produced → lowest rate of reaction

Optimal: Folds best → highest product produced → highest rate of reaction

Below: Denatured structure → nothing produced → lowest rate of reaction

Affecting an enzymes Ion Concentration affects chemical reaction (Na+ & Cl- ions)

Above: Denatured structure → nothing produced → lowest rate of reaction

Optimal: Folds best → highest product produced → highest rate of reaction

Below: Denatured structure → nothing produced → lowest rate of reaction