Biochemistry

Lecture 11

Common Biochemical Reaction Types

Electrophiles

Nucleophiles

Nucleophilic Substitution

Nucleophilic Substitution

Nucleophilic Acyl Substiution

(Group Transfer Reaction)

Nucleophilic Addition

Carbonyl Condensation

Carbonyl Condensation

Elimination

Oxidation and Reduction

Overview of Energy Metabolism

FATS POLYSACCHARIDES PROTEINS

Fatty Acids, Glucose and Amino Acids

Glycerol other sugars

Stage I Digestion

Acetyl CoA

Stage II Anaerobic

TCA cycle CO2

CoA

e-

ADPATP

O2Oxidative

Phosphorylation

Stage III Aerobic

Principles of Regulation• The flow of metabolites through the

pathways is regulated to maintain homeostasis

• Sometimes, the levels of required metabolites must be altered very rapidly– Need to increase the capacity of glycolysis

during the action– Need to reduce the capacity of glycolysis after

the action– Need to increases the capacity of

gluconeogenesis after successful action

Rates of a Biochemical Reaction

• Rates of a biochemical reaction depend on many factors• Concentration of reactants• Activity of the catalyst

– Concentration of the enzyme– Intrinsic activity of the enzyme

• Concentrations of effectors– Allosteric regulators– Competing substrates– pH, ionic environment

• Temperature

Reactions Far From Equilibrium are Common Points of Regulation