U1B enzymes

what are enzymes

• biological catalyst

• speed up chemical reactions without being used up

• usually proteins

what is the enzyme structure

• protein molecules

• made up of amino acid residue joined together by peptide links

enzymes have either an alpha helix or beta pleated shape what makes there characteristic

• hydrogen bonds between amino acid

• protien molecules give molecules characteristic shape

enzymes have a tertiary strucutre why is this important

determines how enzyme works

what is the lock and key theory

• substrate has a specific shape

• fits exactly into the active site on enzyme molecules

what is specificity?

one enzyme reacting with a specific substrate

what is the collision theory

reaction takes place when 2 molecules collide with enough energy to overcome activation energy

what is meant by activation energy

the energy needed to get a reaction going

how do you form a enzyme-substrate complex

active site on the enzyme bind with a substrate

what are 3 factors affecting enzyme activity

• temperature

• pH

• concentration

why is temperature important during enzyme activity

1) temp increases

2) enzyme molecules vibrate

3) vibration breaks some of the bonds

4) active site changes shape

5) no longer an enzyme-substrate complex

6) denatured enzyme is non functional

why is concentration important during enzyme activity

• more enzymes= more collisions

• more collisions= more enzyme-substrate complexes

why pH important during enzyme activity

• enzyme optimum temp is pH 7

• pepsin works best at pH 2

what do acids and alkalis have in terms of ions

Acid= lots of H+ ions

Alkalis= few H+ ions