Regents Biology Enzymes – Chapter 2.4

Regents Biology A. Flow of energy  Life is built on chemical reactions

Regents Biology B. Chemical reactions of life  Processes of life  building macromolecules  Dehydration synthesis  breaking down macromolecules  Hydrolysis ++

Regents Biology C. Enzymes  How important are enzymes?  all chemical reactions in living organisms require enzymes to work  enzymes speed up reactions  Act as catalysts ++ enzyme We can’t live without enzymes!

Regents Biology D. Activation Energy  Is energy needed to get a reaction started  Enzymes act by lowering the activation energy

Regents Biology E. Enzymes are proteins  Each enzyme is the specific helper to a specific reaction  needs to be the right shape  are named for the reaction they help  sucrase breaks down sucrose  DNA polymerase builds DNA Oh, I get it! They end in -ase

Regents Biology F. Enzymes aren’t used up  Enzymes are not changed by the reaction  used only temporarily  re-used again for the same reaction enzyme substrateproduct active site

Regents Biology G. It’s shape that matters!  Lock & Key model  shape of enzyme & substrate must ‘fit’  specific enzyme for each reaction

Regents Biology 1 2 3

H. What affects enzyme action?  Correct protein structure (amino acid chain)  Temperature  pH (acids & bases)  why? enzyme has to be right shape

Regents Biology I. Temperature  Effect on rates of enzyme activity  Optimum temperature  greatest number of collisions between enzyme & substrate  human enzymes  35°- 40°C  Raise temperature (boiling)  denature protein = unfold = lose shape

Regents Biology 37° Temperature temperature reaction rate What’s happening here?! What is optimum temp for human enzymes?

Regents Biology J. pH  Effect on rates of enzyme activity  changes in pH changes protein shape  most human enzymes = pH 6-8  pepsin (stomach) = pH 3  trypsin (small intestines) = pH 8

Regents Biology 7 pH reaction rate stomach pepsin intestines trypsin What’s happening here?! Which environment does pepsin work best – acidic or basic?

Regents Biology How do cold-blooded creatures do it?

Regents Biology For enzymes… What matters? SHAPE!

Regents Biology Enzyme vocabulary  Enzyme  helper protein molecule  Substrate  molecule that enzymes work on  Products  what the enzyme helps produce from the reaction  Active site  part of enzyme that substrate molecule fits into

Regents Biology Order of amino acids  Wrong order = wrong shape = can’t do its job! DNA chain of amino acids folded protein right shape! wrong shape!

Regents Biology Examples  synthesis  digestion ++ enzyme