1.4 proteins Flashcards
how many different amino acids are there
20
where are amino acids made
made in the Golgi and then modified into glycoproteins
what three things does and amino acid have
- amino group
- carboxyl group
- R group (which is the thing that changes for each amino acid)
what bond bonds the amino and carboxyl group together
peptide bond
what are the 4 structures of a protein
primary
secondary
tertiary
quaternary
what is the primary structure
the sequence of amino acids
what are the two types of secondary structure
alpha helix
beta pleated sheet
what are the tree bonds that bond the tertiary structure
ionic
hydrogen
disulphide
what is the structure of a tertiary protein
3D
globular
fibrous
what is the quaternary structure
several polypeptide chains joined together sometimes with a non-protein molecule
what does an enzyme do
lowers the activation energy needed to start a reaction
describe the steps of the induced fit model
- the substrate gets close in proximity with the enzyme
- the active site changes shape slightly so it is complementary to the substrate
- this forms an E-S (enzyme-substrate) complex
- the enzyme then returns to its original shape to push out the two product molecules and is free to bind to another substrate
what are the 4 factors affecting enzymes activity
Temperature
pH
Enzyme concentration
Substrate concentration
how does temperature affect the enzymes activity
more temp = more kinetic energy leading to more successful collision
however if the temperature gets too high tertiary bonds are broken and the enzymes active site will denature so less E-S complexes as less successful collisions
how does pH affect the enzymes activity
rises with pH until reaches optimum and then decreases activity as enzymes denature at both too acidic and too alkali circumstances
how does enzyme concentration affect enzyme activity
the greater the amount of enzyme concentration the more likely there will be successful collisions
the rate will plateau when all active sites are full.
how does substrate concentration affect enzyme activity
as the reaction proceeds more and more enzymes active sites are filled until all the substrate molecules occupy the active sites
this is called saturation of the active sites
name the two types of inhibitors
competitive and non-competitive
describe how a competitive inhibitor works
a competitive inhibitor bonds to the active site of the enzyme preventing the substrate from bonding therefore stopping an E-S complex
describe how a non-competitive inhibitor works
the inhibitor binds to the enzyme (not at the active site) which then causes a conformational change to the active site making the enzyme and substrate no longer complementary to each other
