The Energy of Life Chapter 8.4

BIG Idea 2 Biological systems utilize free energy and molecular building blocks to grow, to reproduce, and to maintain dynamic homeostasis.

Molecular Building blocks Biological Atoms: Carbon Hydrogen Nitrogen Oxygen Phosphorus Sulfur Biological Molecules: Water (H2O) Carbohydrates Lipids Proteins Nucleic Acids

biochemical reactions Molecules rearrange within a living organisms for various processes essential for life. These biochemical reactions are facilitated by a type of protein called an enzyme.

Enzyme Structure The most structurally sophisticated molecules in existence Synthesized through gene expression (DNA  RNA  Protein)

Enzyme Function (beginning) Biochemical reactions are usually not spontaneous Initial investment of energy to start a reaction Enzymes lower the Ea of a reaction

Enzyme Function (middle) Enzymes and substrates interact at the active site: Induced Fit: enzyme changes shape Substrate is broken down or built up Every enzymes is substrate specific! Hexokinase (a) without (b) with glucose substrate

Enzyme Function (end) Enzymes are not used up in the reaction

Common Enzymes in your Body Amylase: in your mouth breaks down sugar Peptidase in your stomach break down proteins Lipase: in your small intestine break down lipids ~2000 enzymes in your body working right now!!!

Regulating Enzymes

Denaturing enzymes (limit range) Heat: Denatures enzymes pH: Acids or bases denature enzymes

Heat

pH

Inhibitors (Turn off) Competitive Noncompetitive Similar in shape and attach to active site disabling the enzyme Noncompetitive Bind to allosteric site of the enzyme altering the shape of the active site

Cofactors & Coenzymes (turn on) Helper molecules which regulate enzyme activity Cofactors: inorganic molecules Coenzymes: organic molecules