Chapter 4- amino acids and proteins Flashcards
(28 cards)
1
Q
proteins are made of_______
A
aa linked together into polymers
2
Q
aa differ in________
A
the R group/ side chain
- what gives the aa the physical and chem properties to distinguish it from the others
same in the backbone of the struc
3
Q
4 broad categories of aa
A
- acidic
- basic
- non polar
- polar
4
Q
physiological pH=
A
7.4
5
Q
A
- Aspartic Acid
- Asp
- D
- acidic amino acid
- has carboxylic acid functional group/ R group (pKa= 4)
- side chain is acidic
aspartate; how this is at physiological pH. At physiological pH it is deprontonated and negative charge
6
Q
A
- Glutamic Acid
- Glu
- E
- acidic amino acid
- has carboxylic acid functional group/ R group (pKa= 4)
- side chain is acidic
Glutamate; how this is at physiological pH. At physiological pH it is deprontonated and negative charge
7
Q
A
- Lysine
- Lys
- K
- basic amino acid bc has basic R group side chains
- pKa side chain= 10
- protonated at physiological pH
- positively charged at physiological pH
8
Q
A
- Arginine
- Arg
- R
- basic amino acid bc has basic R group side chains
- pKa side chain= 12
- protonated at physiological pH
- positively charged at physiological pH
9
Q
A
- Histidine
- His
- H
- basic amino acid bc has a basic R group side chain
- pKa side chain= 6.5, therefore close to physiological pH
- at pH=7.4, can be protonated or unprotonated; acts as both an acid and a base
- readily available to be a proton acceptor or donor, therefore it is found at protein active sites
- positive charge
10
Q
A
- Glycine
- Gly
- G
- smallest aa
- non polar aa
- aliphatic side chains meaning have hydrocarbon side chains with a removed H atom (CH3)- methyl group
- neutral charge at physiological pH
- hydrophobic residues tend to associate with eachother, rather than with water. Therefore they are found in the interior of globular proteins away from water
11
Q
A
- Alanine
- Ala
- A
- non polar aa
- aliphatic side chains meaning have hydrocarbon side chains with a removed H atom (CH3)- methyl group
- neutral charge at physiological pH
- hydrophobic residues tend to associate with eachother, rather than with water. Therefore they are found in the interior of globular proteins away from water
12
Q
A
- Valine
- Val
- V
- non polar aa
- aliphatic side chains meaning have hydrocarbon side chains with a removed H atom (CH3)- methyl group
- neutral charge at physiological pH
- hydrophobic residues tend to associate with eachother, rather than with water. Therefore they are found in the interior of globular proteins away from water
13
Q
A
- Leucine
- Leu
- L
- non polar aa
- aliphatic side chains meaning have hydrocarbon side chains with a removed H atom (CH3)- methyl group
- neutral charge at physiological pH
- hydrophobic residues tend to associate with eachother, rather than with water. Therefore they are found in the interior of globular proteins away from water
14
Q
A
- Isoleucine
- Ile
- I
- non polar aa
- aliphatic side chains meaning have hydrocarbon side chains with a removed H atom (CH3)- methyl group
- neutral charge at physiological pH
- hydrophobic residues tend to associate with eachother, rather than with water. Therefore they are found in the interior of globular proteins away from water
15
Q
A
- Phenylalanine
- Phe
- F
- non polar aa
- aromatic
- neutral charge at physiological pH
- hydrophobic residues tend to associate with eachother, rather than with water. Therefore they are found in the interior of globular proteins away from water
16
Q
A
- Tryptophan
- Trp
- W
- largest aa
- non polar aa
- aromatic
- neutral charge at physiological pH
- hydrophobic residues tend to associate with eachother, rather than with water. Therefore they are found in the interior of globular proteins away from water
17
Q
A
- Serine
- Ser
- S
- Polar aa
- hydroxyl group are modified by attachment of a phosphate group by kinases
- neutral charge at physiological pH
- hydrophilic
18
Q
A
- Threonine
- Thr
- T
- Polar aa
- hydroxyl group are modified by attachment of a phosphate group by kinases
- neutral charge at physiological pH
- hydrophilic
19
Q
A
- Tyrosine
- Tyr
- Y
- Polar aa
- hydroxyl group are modified by attachment of a phosphate group by kinases
- neutral charge at physiological pH
- hydrophilic
20
Q
A
- Asparagine
- Asn
- N
- Polar aa
- neutral charge of physiological pH
- hydrophilic
21
Q
A
- Glutamine
- Gln
- Q
- Polar aa
- neutral charge
- hydrophilic
22
Q
A
- Cystine
- Cys
- C
- Polar aa
- neutral charge
- hydrophilic
- contains a thiol (sulfhydryl)
- disulphide bonds
23
Q
A
- Methionine
- Met
- M
- non polar aa
- neutral charge
- contains a thioester
24
Q
A
- Proline
- Pro
- P
- non polar aa
- neutral charge
- has consequences for protein folding bc the side chain secondary amino group and distinctive ring structures
- makes sharp turns
25
Nine essential aa that cannot be synthesized by humans and must be obtained from the diet
- Lysine
- Histidine
- Threonine
- Valine
- Leucine
- Isoleucine
- Phenylalanine
- Tryptophan
- Methionine
" PVT TIM HALL"
26
Zwitterion
-molecule where positive and negative charges balance is called a dipole ion/ zwitterion
27
Isoelectric point (pI)
- pH where the molecule is uncharged
- where the charge is zero
28
consequences of proline
- forces a kink in the polypep chain
- removes the H bonded to the N, on the proline. This disrupts the pattern of the backbone
