proteins Flashcards
1
Q
what is an amino acid?
A
a monomer which makes up proteins
2
Q
what does the shape/function of a protein depend on?
A
sequence, type and number of amino acids
3
Q
how many amino acids are there?
A
20
- 12 non-essential
- 8 essential
4
Q
describe the structure of an amino acid
A
- central carbon
- NH2 amine group on left
- COOH carboxylic acid group on right
- H on bottom
- R group on top
5
Q
how are proteins joined?
A
by peptide bonds
6
Q
describe how a peptide bond forms
A
- hydroxyl from carboxyl and hydrogen on amine bond and release molecule of water
- remaining carbon and nitrogen of adjacent amino acid bond forming peptide bond
- condensation reaction
7
Q
describe the primary structure of a protein
A
- sequence of amino acids
- peptide bonds
8
Q
describe the secondary structure of a protein
A
- initial folding of polypeptide chain
- alpha helix
- beta pleated
- hydrogen bonding
9
Q
describe the tertiary structure of a protein
A
- further coiling of secondary structure
- 3D
- ionic, disulphide, hydrophilic/hydrophobic, hydrogen
10
Q
describe the quaternary structure of a protein
A
- 2+ polypeptide chains
11
Q
breakdown of peptides
A
- proteases
- hydrolysis reaction
12
Q
what are the two types of proteins?
A
globular
fibrous
13
Q
globular protein
A
- roughly spherical
- irregular amino acid sequence
- soluble in water
14
Q
fibrous protein
A
- long strands
- repetitive amino acid sequence
- insoluble in water
15
Q
insulin
A
- globular
- regulation of blood glucose concentration
- specific shape
16
Q
haemoglobin
A
- globular
- four polypeptides
- 2 alpha and 2 beta subunits
- conjugated
- iron haem group
17
Q
enzymes
A
- globular
- catalyses chemical reactions
18
Q
conjugated protein
A
- globular
- contain non-protein prosthetic group
19
Q
keratin
A
- fibrous
- support and protection for hair, skin, nails
- insoluble
20
Q
elastin
A
- fibrous
- found in elastic fibres
- present in vessel walls and alveoli
21
Q
collagen
A
- fibrous
- has flexibility
- connective tissue found in skin, tendons, ligaments
