Proteins Flashcards
How to test for proteins
Biuret test
add sodium hyroxide and copper sulphate
lilac (present)
Transcription
DNA helicase attaches to the DNA double helix to unwind and break the hydrogen bonds
RNA polymerase lines up free nucleotides along the template using complementary base pairing and forms hydrogen bonds between them
Once a stop codon is reached the RNA polymerase stops and the antisense strand and the mRNA strand are separated
DNA recoils and mRNA leaves the nucleus
proteins definition
long chains of amino acids
carboxyl group, amine group attached to carbon, R group and H
what bond joins amino acids together
peptide bonds
4 structures of proteins
primary
secondary
tertiary
quaternary
primary structure
sequence of amino acids
(one amino acid could change the whole protein)
3 bases of DNA are degenerate (code for the same amino acid)
secondary structure
hydrogen bonding
coil into alpha helix or beta pleated sheets
tertiary structure
folded further
3D structure
ionic bonding, disulfide bonds, hydrogen bonds, hydrophobic and hydrophilic reactions
quaternary structure
the way that the polypeptide chains assemble together
haemoglobin is made up of four polypeptide chains
examples of globular proteins
(hydrophilic r groups are pushed to the outside making them insoluble)
haemoglobin
insulin
amylase
haemoglobin
contains prosthetic haem groups which contain iron for oxygen to bind to
red pigament
insulin
2polypeptide chains held by disulfide bonds
regulates blood glucose levels
amylase
breaks down starch
fibrous proteins
insoluble and strong
collagen
keratin
elastin
collagen
bone
skin
muscle
