[Unit 1.4] Proteins Flashcards
Biological Molecules
why will ROR never peak with non competitive inhibitors present
the effect of inhibitor cannot be overcome by adding more substrate
how do non competitive inhibitors work
binds to a site other than the active site.
other site changes shape
-changes tertiary structure
-changes active site shape
substrate can no longer fit
what is the dilution effect
for competitive inhibitors: the effect of the inhibitor can be overcome by adding more substrate
how do competitive inhibitors work
they have a similar shape to the substrate. and they compete for active site.
what is an inhibitor
substance that interferes with functionality of active site. reducing activity. prevents formation of e-s complexes
they have a temporary effect.
how does increasing the concentration of substrate increase the ROR
as the amount of substrate increases, there are more substrates so more e-s complexes formed, but not all active sites are OCCUPIED. ROR increases until all active sites are occupied and the maximum e-s complexes have been formed. after this point the substrate conc. is no longer a limiting factor. increasing it makes no effect on ROR. all active sites are occupied
what is an enzyme substrate complex
when the active site has changed shape to accommodate for substrate; when they have bound together
How do enzymes lower activation energy?
Induced Fit Model:
active site changes shape to as it binds to substrate
Mechanical pressure stresses and breaks bonds
What is the induced fit model
active site changes shape as it binds to substrate due to bonds forming between R groups.
This forms enzyme-substrate complex
What are enzymes?
globular tertiary proteins that lower activation energy (biological catalyst)
describe the structure of protein [5]
-protein is a polymer of amino acids
-joined by peptide bonds
-formed by condensation
-primary structure is type, order and number of amino acids
-secondary structure is folding of polypeptide chain due to hydrogen bonding
-tertiary structure is 3d folding due to disulphide bridges and ionic bonds
-quaternary structure is 2 or more polypeptide chains usually with prosthetic group
functions of fibrous proteins
extended structure
insoluble in water
tendons
bones
muscle
hair
skin
functions of globular proteins
compact
soluble in water
enzymes
hormones
transport
immune response
Different bonds in secondary and tertiary
hydrogen bonds
disulphide bridges
ionic bonds
hydrophobic interactions
quaternary structure
2+ polypeptide chains. often has non-protein groups associated with (prosthetic group)
tertiary structure
molecule bends and folds into a 3d globular shape. Variety of bonds stabilising structure
beta pleated sheet secondary structure
amino acid chain folds back on itself. forming anti parallel chains. structure stabilised with hydrogen bonds
alpha helix secondary structure
coiled into right handed helix. hydrogen bonds stabilise structure
secondary structure
spatial arrangement of atoms. either alpha helix or beta pleated sheet
primary structure
number, type and sequence of amino acids
what bond do two amino acids form
peptide bond
Whats the name of the bond that amino acids form
peptide bond
via condensation
state all the possibilities (with examples) and ergo properties of the variable groups in amino acids [4]
non polar (hydrocarbon chain), hydrophobic
polar (hydroxyl group), hydrophilic
acidic (carboxylic acid group), negatively charged
basic (amine group) positively charged
uses of proteins
antibodies
antigens
hormones
haemoglobin
enzymes
In general, SHAPE is vital for function
chemical structure of an amino acid
amine group is basic
carboxyl group is acidic
together, the molecule is neutral
Test for proteins
add bieurets solution. will turn from blue to purple/lilac
