Flow of energy through life  Life is built on biochemical reactions

Important vocabulary  Catalyst  Speeds up chemical reaction  Enzyme  Type of catalyst aka helper molecule in living organisms  Substrate  molecule that enzymes work on  Enzyme-substrate complex  enzyme & molecule temporarily joined  Active site  part of enzyme that substrate molecule fits into

What do enzymes do?  Enzymes speed up reactions  Build molecules  synthesis enzymes  Break down molecules  digestive enzymes + enzyme + We can ’ t live without enzymes!

Enzymes are specific  Each enzyme is the specific helper to a specific reaction  each enzyme needs to be the right shape for the job  enzymes are named for the reaction they help  sucrase breaks down sucrose  proteases breakdown proteins  lipases breakdown lipids  DNA polymerase builds DNA Oh, I get it! They end in -ase

It’s shape that matters!  Lock & Key model  shape of protein allows enzyme & substrate to fit  specific enzyme for each specific reaction

Enzymes are re-usable  Enzymes are not changed by the reaction  used only temporarily  re-used again for the same reaction with other molecules  very little enzyme needed to help in many reactions enzyme substrateproduct active site

Let’s See It In Action!!! hill.com/sites/ /student_view0/ chapter2/animation__how_enzymes_wor k.html

What affects enzyme action?  Correct protein structure  Temperature  human enzymes = 35°- 40°C (body temp = 37°C)  pH (acids & bases)  most human enzymes = pH 6-8

Enzyme concentration  Effect on rates of enzyme activity  increase amount of enzyme = increase how fast the reaction happens  more enzymes = more frequently they collide with substrate

Enzyme concentration amount of enzyme reaction rate

Substrate concentration  Effect on rates of enzyme activity  increase amount of substrate = increases how fast the reaction happens  more substrate = more frequently they collide with enzyme

Substrate concentration amount of substrate reaction rate

Other important things about enzymes  Coenzymes  substrates for enzymes and do not form a permanent part of the enzymes' structures.  Competitive inhibitors  form of enzyme inhibition where binding of the inhibitor to the active site on the enzyme prevents binding of the substrate

For enzymes… What matters? SHAPE!

Let’s See It In Action!!! hill.com/sites/ /student_view0/ chapter2/animation__how_enzymes_wor k.html