proteins Flashcards
what are proteins made from?
amino acid monomers - they join through a condensation reaction forming a peptide bond
how is a dipeptide made?
by joining two amino acids
what are the four structures of proteins?
primary, secondary, tertiary and quaternary structure
what is the primary structure?
sequence of amino acids in a polypeptide chain joined by peptide bonds.
what is the secondary structure?
initial folding of the polypeptide chain due to hydrogen bonding between amino acids.
two main types are alpha helices and beta pleated sheets.
what is the tertiary structure?
further folding of the secondary protein (polypeptide) due to interactions between the variable groups.
protein becomes functional and 3D, forming hydrogen and ionic bonds and disulfide bridges.
what is the quaternary structure?
this is where multiple polypeptide chains are joined together.
what are the two types of protein?
globular and fibrous
describe globular proteins.
round and ball shaped.
have metabolic functions.
example - haemoglobin.
describe fibrous proteins.
long and narrow.
have a structural function.
example - collagen, keratin.
describe the test for proteins?
add biuret reagent, positive result would be lilac.
describe the structure of an amino acid.
COOH = carboxyl group
R = variable group
H2N = amine group
describe how amino acids join together.
via a condensation reaction between carboxyl group and amine group, removing water forming a peptide bond.
