Proteins Flashcards
Protein elements
Carbon, hydrogen, oxygen, nitrogen and sometimes sulfur
Protein general formula
R-CH(NH2)-COOH
Amino acid
Has an amine group(basic) and carboxyl group (acidic)
R group
Variable group- 20 types of amino acids
Protein
polymer of amino acids
Dipeptide
Two amino acids joined together by condensation with a peptide bond
Primary structure
Sequence of AAs in a polypeptide chain by peptide bonds
Secondary structure
folding of the polypeptide chain into an alpha helix or beta pleated sheet
What bonding in alpha helix
Hydrogen bonding between the =O on -CO groups and the -H on -NH
Tertiary structure
Folding of the alpha helix to form specific 3D shapes
Bonds in tertiary structure
Hydrogen
Ionic
Hydrophobic interactions
Enzymes are examples of what structure
Tertiary
Quaternary structure
2 or more polypeptide chains joined together
Globular proteins
Fold into a ball shape
Hydrophobic R groups in, hydrophilic out
Globular proteins functions
Water soluble
Metabolic role- enzymes, hormones, antibodies. eg. haemoglobin carries o2 with 4 tertiary structures
Fibrous proteins
long fibres of regular repetitive sequences and cross links
Fibrous proteins functions
Insoluble
structural roles, eg. collagen triple helix in tendons, bones, cartilage
ALSO myosin and keratin