Proteins and Enzymes Flashcards
What is a protein?
A polymer built up of one or more amino acids
What is significant about an amino acids R group?
The R group is different in all amino acids
What groups does an amino acid contain?
- An amine group- A carboxylic acid group- A r group- A hydrogen
What is the bond called that forms between amino acids?
A peptide bond
What reaction forms a dipeptide?
A condensation reaction
What is a dipeptide?
Two amino acids joined by a peptide bond
What is the primary structure of a protein?
The sequence of amino acids
What is the secondary structure of a protein?
Coiling and folding of the polypeptide chain. A helixes and Beta pleated sheets
What is a proteins tertiary structure?
Its final 3D shape, Extensive Coiling and folding of the polypeptide chain with Peptide bonds(primary), hydrogen bonds(secondary) and ionic bonds and disulphide bridges
What is a proteins quaternary structure?
A protein made from multiple polypeptide chains
What is the test for proteins called?
The biuret test
How do you carry out the test for proteins?
Add the biuret reagent (Copper Sulphate), purple indicates protein present
How do you answer a protein shape question?
The tertiary structure of the active/binding site is complimentary to the shape of the substrate and can form an enzyme-substrate complex/an antibody-antigen complex
How do you answer a non-functional protein question? (mutation)
A change in the proteins primary structure causes changes in the proteins tertiary structure which changes the shape of the active site therefore the substate is no longer complimentary and cannot form an enzyme-substrate complex
Why does the rate of enzyme catalysed reactions increase up to the optimum temperature?
As temperature increases molecules vibrate more therefore more collisions will take place with a higher percentage being successful and colliding with the activation energy therefore more enzyme - substrate complexes are formed
What happens to enzymes as the pH increases/decreases away from the optimum?
enzyme rate of reaction decreases as the increase/decrease in OH- or H+ ions interact with the hydrogen and ionic bonds causing the tertiary structure to change and the active site will no longer be complimentary to the substrate and an enzyme-substrate complex won’t be able to form
Why does rate of reaction increase as enzyme concentration increases?
more successful enzyme-substrate collisions will take place at a quicker rate therefore more enzyme-substrate complexes will form
Why does rate of reaction increase as substrate concentration increases?
more successful enzyme-substrate collisions will take place at a quicker rate therefore more enzyme-substrate complexes will form
How do competitive inhibitors work?
They have a similar shape to the substrate and can bind to the active site, preventing enzyme-substrate complexes from forming
How do non-competitive inhibitors work?
They bind to the enzyme at an alternative location to the active site which changes the shape of the active site so that enzyme-substrate complexes can no longer form
