Amino Acids Flashcards
(110 cards)
1
Q
What are the structures of typical amino acids found in proteins?
A
Carbon atom (a-carbon atom) covalently linked to:
(a) amino group (-NH2)
(b) carboxyl group (-COOH)
(c) variable side chain (R-group)
(d) hydrogen (-H)
2
Q
How many amino acids are there?
A
20
3
Q
Amino acids consist of what 4 groups connected to the central alpha carbon?
A
(a) amino group (-NH2)
(b) carboxyl group (-COOH)
(c) variable side chain (R-group)
(d) hydrogen (-H)
4
Q
At physiological pH, the amino group is _______
A
Protonated. (-NH3+)
5
Q
At physiological pH, the carboxyl group is ______
A
Unprotonated. (-COOH-)
6
Q
What makes up a tetrahedral amino acid structure?
A
- 4 equilateral triangles
- Alpha carbon in the middle
- 4 vertices (amino group, carboxyl group, R side chain, alpha carbon)
7
Q
How many Nonpolar/Hydrophobic Amino Acids are there?
A
8
8
Q
What are the 8 nonpolar/hydrophobic amino acids?
A
Alanine (Ala)
Valine (Val)
Leucine (Leu)
Isoleucine (Ile)
Proline (Pro)
Methionine (Met)
Phenylalanine (Phe)
Tryptophan (Trp)
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9
Q
ALA
A
Alanine
10
Q
VAL
A
Valine
11
Q
LEU
A
Leucine
12
Q
ILE
A
Isoleucine
13
Q
PRO
A
Proline
14
Q
MET
A
Methionine
15
Q
PHE
A
Phenylalanine
16
Q
TRP
A
Tryptophan
17
Q
A
A
Alanine
18
Q
V
A
Valine
19
Q
L
A
Leucine
20
Q
I
A
Isoleucine
21
Q
P
A
Proline
22
Q
M
A
Methionine
23
Q
F
A
Phenylalanine
24
Q
W
A
Tryptophan
25
Why are amino acids nonpolar/hydrophobic?
They are made of just carbons & hydrogens. Either in forms of chain, cyclic structures, or linear
26
Alanine (Ala, A) R chain
alkyl chain R group
(linear chain of carbon & hydrogens)
(short with branches)
27
Valine (Val, V) R chain
alkyl chain R group
(linear chain of carbon & hydrogens)
(short with branches)
28
Leucine (Leu, L) R chain
alkyl chain R group
(linear chain of carbon & hydrogens)
(short with branches)
29
Isoleucine (Ile, I) R chain
alkyl chain R group
(linear chain of carbon & hydrogens)
(short with branches)
30
Proline (Pro, P) R chain
unusual cyclic structure
31
Methionine (Met,M) R chain
sulfur containing
32
Phenylalanine (Phe, F) R chain
aromatic
(6 sided ring structure)
33
Tryptophan (Trp, W) R chain
aromatic
(6 sided ring structure)
34
What makes prolines structure unique?
It has two linkage points to the central carbon from the R-Side chain
35
How many polar/hydrophilic amino acids are there?
8
36
What are the polar/hydrophilic amino acids?
Asparagine (Asn)
Glycine (Gly)
Histidine (His)
Glutamine (Gln)
Threonine (Thr)
Serine (Ser)
Tyrosine (Tyr)
Cysteine (Cys)
As Gly hits glutes, threo seriously types cysts
37
Gly
Glycine
38
Ser
Serine
39
Threonine
Thr
40
Tyr
Tyrosine
41
Asn
Asparagine
42
Gln
Glutamine
43
His
Hisidine
44
G
Glycine
45
S
Serine
46
T
Threonine
47
Y
Tyrosine
48
C
Cysteine
49
N
Asparagine
50
Q
Glutamine
51
H
Histidine
52
Glycine (Gly, G) R chain
Simplest R group (H)
* Doesn't fit with polar or nonpolar *
53
Threonine (Thr, T) R chain
Hydroxyl (OH) at end of R side chain
Branched
53
Serine (Ser, S) R chain
Hydroxyl (OH) at end of R side chain
Linear
54
Tyrosine (Tyr, Y) R chain
Hydroxyl (OH) at end of R side chain
Ring
55
Cysteine (Cys, C)
Sulfur containing (SH)
56
Asparagine (Asn, N)
Amide in R group (NH2)
Linear
57
Glutamine (Gln, Q)
Amide in R group (NH2)
Branched
58
Histidine (His, H)
Amide in R group (NH2)
Ring
59
What are the R side chains of polar amino acids?
-OH -NH or -SH
60
What are the R side chains of nonpolar amino acids?
-CH2 -CH3 - S
61
How many acidic amino acids are there?
2
62
What are the acidic amino acids?
Aspartic Acid (Asp, D)
Glutamic Acid (Glu, E)
63
Aspartic acid (Asp, D) R chain
carboxyl (COOH) in R group
64
Glutamic Acid (Glu, E)
carboxyl (COOH) in R group
65
What does acidic amino acid mean?
Net negative charge at PH 7.0
66
How many basic amino acids are there?
2
67
What are the basic amino acids?
Lysine (Lys,K)
Arginine (Arg, R)
68
Lysine (Lys,K) R chain
positively charged nitrogen-containing
69
Arginine (Arg, R) R chain
positively charged nitrogen-containing
70
What does basic amino acid mean?
net positive charge at neutral PH
71
What are the 3 groups in the charged amino acids?
- COO-
- NH3+
= NH2+
72
Hydroxylysine is a modified ____ found in ____
lysine, collagen
73
Acetyllysine is a modified ____ found in _____
lysine, histone proteins
74
Thyroxine has added ____ and lost other atoms
4 iodines
75
Carboxyglutamic acid is modified ____ involved in ____
glutamic acids, blood clotting
76
Carboxyglutamic acid has two added ___
carboxyl groups
77
Thyroxine makes ____
thyroid hormones
78
Acetyllysine has an added ___ linked through the amino acid
acetyl
79
Acetyllysin allowed for ___ and the modification is later removed to allow histones to rebind to DNA
DNA seperation
80
Acetyllysin ____ lysine to allow for DNA strand seperation
neutralized
81
The cationic form of an amino acid is at ___ pH
low
82
What group is neutral when the amino acid is in cationic form?
carboxyl
83
What group is positively charged when the amino acid is in cationic form?
amino
84
What is released when going from cationic form to zwitterion form (neutral)?
H+
85
What is negatively charged when the amino acid is in neutral/zwitterion form?
carboxyl
86
What group is positively charged when the amino acid is in neutral/zwitterion form?
amino
87
What is lost when going from zwitterion form to anionic form?
H+
88
What group is negatively charged in anionic form?
carboxyl
89
What group is neutral in anionic form?
amino
90
Charge of cationic form
+1
91
pH of cationic form
pH = 1
92
Charge of zwitterion form
0
93
pH of zwitterion form
pH = 7
94
Charge of anionic form
-1
95
pH of anionic form
pH = 13
96
The 1 + and 1 - charged groups on the zwitterion atom makes it ______
neutral
97
How is a peptide bond formed?
Reaction of the
1. carboxyl group of one amino acid
&
2. amino group of another
98
Reaction of forming a peptide bond results in the ___ of a water molecule
water
99
CO-NH is a ____ bond
peptide/amide
100
Formation of a peptide bond
1. Two amino acids
2. Removal of a water molecule
3. Formation of the CO-NH
101
What are the two terminal ends of peptide bonds?
1. N (amino end)
2. C (carboxyl end)
102
What are two reactions of amino acids
1. peptide bond
2. disulfide bridge
103
Disulfide bridges involve the _ __ ____ of an amino acid
R side chain
104
What does the formation of a disulfide bridge hekp with?
Folding of protein chains
Forms loops
Stabilizes the 3D protein structure
105
What configuration are proteins naturally in?
L
106
Are disulfide bridges essential?
NO
107
Lab technique of seperating amino acids/proteins
Ion exchange chromatography
108
What amino acid can form a disulfide bridge?
Cysteine
109
Bead used in ion exchange chromatography is ____
negatively charged
