proteins and enzymes Flashcards
describe the induced-fit model of enzyme action and how an enzyme acts as a catalyst (3)
•substrate binds to the active site
•active site changes shape
•reduces activation energy
a competitive inhibitor decreases the rate of an enzyme controlled reaction
explain how (3)
•inhibitor similar shape to substrate
•binds to active site
•prevents enzyme-substrate complex forming
describe how the structure of protein depends on the amino acids it contains (5)
•structure determined by the position of the R group.
•primary structure is the order of amino acids.
•secondary structure is formed by hydrogen bonding.
•tertiary structure is formed by interactions.
•creates an active site in enzymes.
describe how amino acids join to form a polypeptide so there is always NH2 at one end and COOH at the other end (2)
•NH2 joins to COOH group to form a peptide bond.
•there is a free NH2 group on one side.
•there is a free COOH group on another side.
explain how the active site of an enzyme causes a high rate of reaction (3)
•lowers activation energy
•induced fit causes site to change shape
•enzyme substrate complexes causes bond to form/break
describe how a non-competitive inhibitor can reduce the rate of an enzyme-controlled reaction (3)
•attaches to the enzyme at a site other than the active site.
•changes active site.
•no longer complementary so no substrate can fit.
describe how a peptide bond is formed between two amino acids to form a dipeptide (2)
•condensation
•between NH2 and COOH
the secondary structure of a polypeptide is produced by bonds between amino acids
describe how (2)
•hydrogen bonds
•between NH and C=O
two proteins have the same number and type of amino acids but different tertiary structures
explain why (2)
•different sequence of amino acids
•form hydrogen bonding in different places
formation of an enzyme-substrate complex increases the rate of reaction
explain how (2)
•reduces activation energy
•due to bending bonds
