Proteins Flashcards
1
Q
proteins are..?
A
multipurpose molecule
2
Q
function of proteins?
A
- enzymes: pepsin, DNA polymerase
- structure: keratin, collagen
- carriers and transport: hemoglobin, aquaporin
- signals cells: insulin
- receptors
- defense: antibodies
- movement: actin and myosin
- storage: bean seed protein
3
Q
structure of proteins?
A
- monomer: amino acids (20 different)
- polymer: polypeptide
- can be one or more polypeptide folded and bonded together
- large complex molecules
4
Q
three molecules in the structure of proteins?
A
- hemoglobin
- rubisco
- growth hormones
5
Q
structure of amino acids?
A
- central carbon
- amino group
- carbonyl group
- r group, side chain
6
Q
r group?
A
- variable group
- different for each amino acid
- unique chemical properties to each amino acid
7
Q
effects of different r groups and why?
A
- non polar: hydrophobic
- -why? bc of hydrocarbons
- polar: charges and hydrophilic
- -why? bc of oxygen and nitrogen
8
Q
amino acids can be?
A
H+ donors: acids
OR
H+ acceptors: bases
9
Q
sulfur containing amino acids..?
A
- disulfide bridges
- covalent cross between sulfhydryls
- stabilizes 3D
10
Q
peptide bonds?
A
- covalent between NH2 (amine) and COOH (carboxyl)
- C-N bond
- repeated sequence: N-C-C
- can only grow in one direction
11
Q
2 amino acids form a polypeptide chain by…?
A
dehydration synthesis
12
Q
C-N?
A
peptide bond
13
Q
N-C-C
A
amino acid
14
Q
protein function and structure?
A
-3D: twisted folded and coiled
15
Q
primary (1°) structure
A
- order of amino acids in chain
- sequencing of amino acids by DNA
- covalent bonds
16
Q
secondary structure (2°)
A
- localized folding along polypeptide
- H bonds
- a helix (coil)
- b pleated sheet (pleated)
17
Q
tertiary structure (3°)
A
- whole molecule folding
- interactions between distant amino acids
- hydrophobic interactions (nonpolar amino acids cluster away from water)
- h bonds and ionic bonds
- disulfide bridges (S-H)
18
Q
quaternary structure (4°)
A
- more than one polypeptide chain bonded together
- hydrophobic interactions, h bonds, ionic bonds and disulfide bridges
19
Q
denaturation
A
-unfolding a protein
20
Q
conditions that disrupt denaturation?
A
- temp
- pH
- salinity
21
Q
denaturation alters which structures?
A
2°, 3°, 4°
