enzymes Flashcards
what do enzymes do?
biological catalysts that speed up chemical reactions without being used up during the reaction
what is the structure of enzymes?
3D globular proteins with specific tertiary structure
active site that is complementary to the specific substrate
what happens when the substrate binds with the active site?
an enzyme-substrate complex is formed
what does the induced fit model show?
substrate collides with active site
active site molds around substrate molecule
enzyme-substrate complex formed
change in enzymes 3D shape places a strain on substrate which weakens chemical bonds
enzyme-product complex formed
products no longer fit so are released
what is lysozyme?
enzyme found in tears and egg white
antibacterial
breaks down polysaccharides in bacterial cell walls
what does lysozyme do?
catalyses hydrolysis of glycosidic bonds
breaks chains of beta glucoses
what are catabolic reactions?
involve break down of larger molecules into smaller molecules (hydrolysis)
what are anabolic reactions?
involve larger molecules being made from smaller molecules (condensation)
where are enzymes made?
in cells by protein synthesis
what are intracellular enzymes?
enzymes which remain inside the cell
what are extracellular enzymes?
enzymes which are secreted from cells to function
what is the turnover number?
maximum number of substrate molecules an enzyme can convert to product molecules per unit of time
how does temperature affect enzyme activity FIRST PART OF GRAPH?
increases kinetic energy
more successful collisions
optimum temperature
how does temperature affect enzyme activity SECOND PART OF GRAPH?
vibrations in molecules breaks hydrogen bonds
active site changed
enzyme has become denatured
how does varying pH affect enzyme activity FIRST AND LAST PART OF GRAPH?
activity declines as pH moves away from optimum
hydrogen and ionic bonds broken
distorts enzyme shape