biological molecules Flashcards
roles of proteins
catalytic - makes up enzymes
signalling
immunological
hormones and receptors and antibodies
structural - hair, muscle and body tissue
amino acid parts
C in middle
R group
carboxylic acid group
amino group - NH2
H
how many naturally occurring amino acids are there
20
How are proteins formed?
condensation reaction (with loss of water)
forming peptide bonds between individual AA molecule
polypeptide is a long chain of AA
primary structure of protein
simple long chains with no IMF
secondary structure of proteins
hydrogen bonds form causing molecule chain to fold/coil
tertiary structure of proteins
hydrophilic/phobic interactions, H bonds, ionic bonds, disulphide bridges hold molecules together in shape
Quaternary structure of proteins
2 separate polypeptide chains
what bonds do AA form between each other?
hydrophobic - between non-polar sections
where are disulphide bonds formed in proteins?
between 2 cysteine AA
happens if there is a sulphur R group
where are ionic bonds formed in proteins?
between carboxyl and amino group
easily broken by changes in pH
How is the secondary structure of a polypeptide produced by bonds between amino acids?
hydrogen bonds help form secondary structure between NH group and C=O group forming alpha helix and beta pleated sheets
why do proteins with the same number of amino acids have different tertiary structures?
different sequence of AA forms ionic, hydrogen, disulphide bonds in different places
globular protein
in bloodstream
compact, spherical- tightly folded polypeptide chains
transport proteins, enzymes, hormones
soluble e.g insulin
conjugated protein
red blood cells
type of globular protein
haemoglobin - 4 polypeptide chains with ion group
soluble
