Amino Acids and protein structure Flashcards
(24 cards)
amino acids
monomers of all proteins, and all amino acids have the same basic structure
what is a peptide bond
a bond formed when two amino acids are joined by a condensation reaction
what is a protein
large polymers comprised of long chains of amino acids
why are proteins good enzymes
they have a tendency to adopt specific shapes
what are the roles of proteins
- form components in animals, muscles are made of protein
- act as enzymes, antibodies, some hormones
-proteins act as carriers for active transport across the membrane and facilitated diffusion
what is the structure of amino acids
each amino acid contains the elements CHON
amino group
carboxyl group
R group
central carbon
describe the R GROUPS
r groups arent a particular element they are different in each amino acid.
vary in polarity
charge
some are hydrophilic and hydrophobic
what is the r group in glycine
H atom
what is the most simple amino acid
glycine
r group- hydrogen atom
what does protease do
enzymes which catalyses breaking peptide bond
protease in intestine break peptide bonds in digestion.
can break down protein hormones so there effects arent permanent
what is a dipeptide
two amino acids are joined together
polypeptide
when multiple (more than
2) amino acids are joined together by a peptide bond.
what is a primary structure
the sequence of amino acids found in a protein
a change to just one amino acid changes the function
peptide bonds
what is the quaternary structure
more than one polypeptide chain
how many amino acids are there.
20
what is the tertiary structure
coils and pleats fold
3d arrangement
disulphide bonds
ionic bonds
weak hydrophobic interactions between non polar r groups
secondary structure
a helix
b pleated sheets
held by hydrogen bonds
stability
can be broken by hydrogen bonds and high temperature
what is the highest level of protein structure for fibrous proteins-
secondary protein structure is the highest protein level for collagen and keratin
what bonds are only in tertiary structure
disulphide
ionic
hydrophobic interactions
hydrogen
peptide
what bonds are in secondary structure
hydrogen
peptide
what bonds are in primary structure
peptide
how do hydrogen bonds form
between a slight positive charge and atoms with a slight negative charge
between one amino group of one and the carboxyl group of another
disulfide links
r group of one amino acid cytesiene contains sulfur
disulfide bonds formed between the r groups of two cysteines.
STRONG bonds
how do hydrophobic and hydrophilic protein interactions occur
hydrophobic r groups associate together in the centre of the polypeptide avoiding water
hydrophilic r groups are found at the edge of the polypeptide to be close to the water
causing a twisting in the chain and controlling the shape
Tertiary structure
