proteins Flashcards
name basic protein synthesis
DNA - transcription to RNA - translation to protein
name some classes of amino acid
acidic, aromatic, aliphatic(hydrocarbon), basic(nitrogen group), sulphur-containing, uncharged polar
what is a peptide bond
Formation of a covalent bond with the loss of 1 molecule of water
what is the primary structure
The sequence of amino acids in a polypeptide chain
what is the secondary structure
Is the spatial arrangement of amino acid residues that are near each other in the linear sequence
alpha helixes and beta sheets
what is tertiary structure
The spatial arrangement of amino acid residues that are far apart in a linear sequence
what is secondary structure held together by
h bonds
what is tertiary structure held together by
van der Waals Ionic interactions Hydrogen bonds Disulphide bridges Hydrophobic interactions
where and what are disulphide bonds
These are strong covalent bonds between two cysteine residues
They are common in extra-cellular proteins.
also bind the light and heavy chains in antibodies
what is quaternary structure
Refers to the spatial arrangement of individual polypeptide chains in a multi- subunit protein
what happens when a protein is denatured
Decreased solubility
Altered water binding capacity
Loss of biological activity
Improved digestibility
what are the 3 other types of proteins
Glycoproteins
Lipoproteins
Metalloproteins
what are glycoproteins
examples?
Compound composed of protein and carbohydrate
Immunoglobulins
what is glycosylation
post translation modification - where a sugar molecule binds to the protein
what dose glycosylation do/ effect
Protein stabilisation Affect solubility Protein Orientation Signalling Cell recognition
what are lipoproteins
what do they do
examples
Protein and lipids are either covalently or non-covalently bonded together
transport of water-insoluble fats and cholesterol in the blood
HDL, LDL
what are metalloproteins
what are the functions
Protein molecule with a bound metal ion help protein to be/do Enzymes Storage Signalling Transport
what are the 3 structures of proteins
globular , fiborius and membranpous
what do globular proteins do
Enzymes Messengers (hormones) Transporters Stock of amino acids Structural function e.g. actin and tubulin
what do fiborous proteins do
Bone matrices
Muscle fibre
Tendons
Connective tissue
what do membranous do
Relay signals
Membrane transporters
Membrane enzymes
Cell adhesion molecule
what is co-operative binding
the alteration of a proteins shape and assecsibility due to the binding of a molecule
what is collagen
25 percent of proteins in humans (most in humans)
high tensile strength
what type of proteins is a LDL receptor
where is it what dose it do
Glycoprotein
Present on the surface of all cells
Causing the internalisation of LDL - leading to the breakdown of LDL by lysosomes
