3.1.4 Proteins Flashcards
(27 cards)
What are the monomers of proteins?
Amino Acids
What do two amino acids form?
Dipeptide
What do lots of amino acids form?
Polypeptide
What are the 4 main structures of Proteins?
Primary structure
Secondary structure
Tertiary structure
Quaternary structure
What is the structure of an amino acid?
H2N - CHR - COOH
What is the bond that holds together multiple amino acids together?
Peptide bond
What is the R group in an amino acid?
The variable group which is different in the 20 amino acids
What is the primary structure of a protein?
The sequence of amino acids in a polypeptide chain which is determine by DNA
How does the order of amino acids in the primary structure affect its other structures?
The specific order of amino acids will alter where bonds occur and how the protein therefore folds
What is the secondary structure of a protein?
Bending of the primary structure will form alpha-helix or beta-pleated sheets
How does alpha-helix or beta-pleated sheets form?
Hydrogen bonds form between the carboxyl group of an amino acids and the amine group of another
What is the tertiary structure of a protein?
The further folding of the secondary structure
To create a unique 3D structure
Held in place by hydrogen, ionic and disulfide bonds
How is the tertiaty structure held in place?
Hydrogen bonds, Ionic bonds and sometime disulfide bridges if sulur is present in that amino acid
What is the quaternary structure of a protein?
A protein that is made up of more than one polypeptide chain has a quaternary strucutre - Haemogobin is an example
What is the strucutre of an enzyme?
Enzymes are tertiary structure proteins which have an active site.
How do enzymes work?
Enzymes have a specific active site which is complementary to an substrate. They bind together and lower the activation energy required for the reaction to occur.
What are the two models of enzyme action and which one is most;y accepted?
Lock and Key
Induced Fit model - most accepted
What is the lock and key model?
Suggest that the enzyme acts as a lock and the substrate acts as a key which are complementary to each other.
They bind to form an enzyme-substrate complex whch lowers the AE
What is the induced fit model?
Suggesst that the enzyme’s active site is like a glove and is not exactly complenmentary to the substrate which allows for the active site to mould around the substrate so its completely complementary
What are the 5 factors that affect enzyme activity>?
Temperature
pH
Concentration of Substrate
Concentration of enzyme
Inhibitors
How does temperature affect enzyme activity?
If the temperature is to low there is not enough kinetic energy for successful collisions to occur between the enzyme and the substrate but if it is too high then the enzyme denatures
How does pH affect enzyme activity?
Too high or too low of a pH will interfer with the charges of the amino acids which can break the H-bonds or ionic bonds holding the teritiary structure which could lead to it denaturing
Therefore fewer enzyme-substrate complexes form
How does substrate concentration effect enzyme activity?
Insufficent substrate will lead to a slower rate as there will be fewer collions between the enzymes and substrate
How does enzyme concentration effect enzyme activity?
Insufficent enzymes will lead to all active sites being SATURATED so it will be unable to work any faster
