Proteins 2.1.2 (k,l,m,n,o) Flashcards
monomer of a protein?
amino acids
what is formed with two amino acids?
a dipeptide
what is an amino acid chain?
a polypeptide
what is the general structure of an amino acid?
what bonds link amino acids together?
peptide bonds
what reaction forms peptide bonds?
condensations
a molecule of water is produced
what reaction destroys peptide bonds?
hydrolysis
what are the levels to protein structure?
primary
secondary
tertiary
quaternary
what is the primary structure of a protein?
the sequence of amino acids in a polypeptide chain
what bonds are present in the primary structure?
peptide bonds
what is the secondary structure of a protein?
the coiling of the polypeptide chain into:
- alpha helix
- beta pleated sheet
alpha helix
beta-pleated sheet
what bonds are present in the secondary structure?
peptide bonds
hydrogen bonds
what is the tertiary structure of a protein?
the further folding of a polypeptide chain into it’s 3D structure
what bonds are present in the tertiary structure?
ionic
disulfide bridges
hydrophobic-hydrophilic interactions
hydrogen bonds
in the tertiary structure what are the bonds formed between?
the R-groups of a protein
ionic bonding
between oppositely charged R-groups
disulfide bridges
between two R-groups which both contain cysteine
hydrophobic-hydrophilic interactions
between hydrophobic and hydrophilic R-groups
hydrogen bonds
between delta +ve and delta -ve R -groups
what is the quarternary structure?
the interactions between more than one polypeptide chain
the final 3D structure
what are the two types of protein?
globular
fibrous
properties of globular proteins
compact
spherical
water soluble
how are globular proteins water soluble?
they have their hydrophobic R-groups pointing inwards
they have their hydrophilic R-groups pointing outwards
why is water solubility important for globular proteins?
they have to be able to be dissolved in water to be transported
examples of globular proteins
insulin
haemoglobin
catalase
role of insulin
hormone which decreases the blood glucose level
structure of insulin
two polypeptide chains
joined together by disulfide bridges
what is a conjugated protein?
a protein which contains a non-protein element called a prosthetic group
example of a conjugated protein
haemoglobin
what is the prosthetic group in haemoglobin?
Fe2+
structure of haemoglobin
4 polypeptides
with 2 alpha and 2 beta subunits
each subunit contains a prosthetic group of Fe2+
what does the Fe2+ do?
binds to oxygen or carbon dioxide which allows haemoglobin to transport it around the body
why does haemoglobin have to be water soluble?
it needs to be able to dissolve in the blood to be transported around the body
role of catalase
breaks down hydrogen peroxide
structure of catalase
four prosthetic groups
each have their own haem grou[
properties of fibrous proteins
long
insoluble
strong - high tensile strength
properties of fibrous proteins
long
insoluble
strong - high tensile strength
examples of fibrous proteins
collagen
keratin
elastin
properties of collagen
strong
flexible
insoluble
what makes collagen strong?
presence of cysteine means that disulfide bridges are formed which require a lot of energy to overcome
properties of elastin
flexible
