Module 4: Amino Acids Flashcards
1
Q
polymers of amino acids, with each amino acid residue joined to its neighbor by a specific type of covalent bond.
A
Proteins
2
Q
The term _______ reflects the loss of the elements of water when one amino acid is joined to another
A
“residue”
3
Q
How many different amino acids are commonly found in proteins
A
20
4
Q
the first to be discovered in 1806
A
Asparagine
5
Q
the last of the 20 to be found in 1938
A
Threonine
6
Q
was first found in asparagus
A
Aspargine
7
Q
in wheat gluten
A
glutamate
8
Q
was first isolated from cheese (its name is derived from the Greek tyros, “cheese”)
A
tyrosine
9
Q
(Greek glykos,“sweet”) was so named because of its sweet taste
A
glycine
10
Q
Proteins are naturally-occurring, unbranched polymer in which the monomer units are ______
A
Amino Acids
11
Q
what percentage of a cell’s overall mass do Amino Acids account for?
A
15%
12
Q
What elements make up the composition of proteins?
A
Carbon, Hydrogen, Nitrogen, Oxygen, Sulfur
13
Q
an organic compound that contains both
an amino (-NH2) group and a carboxyl group ((-COOH)
A
amino acid
14
Q
The amino acid found in CHON are always
A
α-amino acid
15
Q
an amino acid which the amino group and the carboxyl group are attached to the α-carbon atom
A
α-amino acid
16
Q
the side chain is also called
A
R group
17
Q
The R group is called the
A
side chain
18
Q
how many possible stereoisomers can amino acids have
A
2
19
Q
Are the following non-polar, acidic, basic, or neutral?
Alanine, Glycine, Isoleucine, Leucine, Methionine, Proline, Valine
A
NON-POLAR
20
Q
Are the following non-polar, acidic, basic, or neutral?
Aspartic Acid, Glutamic Acid
A
ACIDIC
21
Q
Are the following non-polar, acidic, basic, or neutral?
Arginine, Histidine, Lysine
A
BASIC
22
Q
Are the following non-polar, acidic, basic, or neutral?
Asparagine, Cysteine, Glutamine, Serine, Threonine, Tyrosine
A
NEUTRAL
23
Q
What type of amino acids are Phenylalanine & Tryptophan?
A
Non-Polar Aromatic
24
Q
has the simplest structure. Although it is formally nonpolar, it’s very small side chain makes no real contribution to hydrophobic interactions
A
Glycine
25
________ has an aliphatic side chain with a distinctive cyclic structure. The secondary amino (imino) group of ________ residues is held in a rigid conformation that reduces the structural flexibility of polypeptide regions containing ________
Proline
26
__________ one of the two sulfur containing amino acids, has a nonpolar thioether group in its side chain
Methionine
27
Can be viewed as a benzyl group
substituted for the methyl group of
alanine, or a phenyl group in place of terminal H of alanine
Phenylalanine
28
The –OH group can form H-bonds, an important functional group in some enzymes
Tyrosine
29
Is a borderline member of aromatic R groups because water can
weakly interact through
H-bonding with the NH ring
Tryptophan
30
2nd primary amino group at terminal position on its aliphatic chain
Lysine
31
Positively charged guanidino group. The guanidine group on side chain contains 3-Natoms of which 2 can easily undergo condensation reaction with carbonyl compounds
Arginine
32
Has imidazole group. Five membered
heterocyclic moiety.
Histidine
33
–carboxyl group has lost its acidic hydrogen atom
Negatively Charged (Acidic) R Groups
34
more polar than phenylalanine due to –OH of tyr and N of try indole ring
Tyrosine & Tryptophan
35
what groups are nonpolar and hydrophobic
R groups
36
what amino acids are positively charged R groups
Lysine, Arginine, Histidine
37
what amino acids are negatively charged R groups
Aspartate and Glutamate
38
what amino acids are polar, uncharged R groups
Serine, threonine, cysteine, Asparagine and Glutamine
39
the only standard amino acid that has a side chain that contains a sulfhydryl group
Cysteine
40
What are the two types of amino acids
essential and non essential
41
what type of amino acids is not produced in the body
essential
42
what type of amino acids are produced by the body
non-essential
43
What amino acids are essential
Phenylanine, Valine, Threonine, Tryptophan, Isoleucine, Methionine, Histidine, Arginine, Leucine, Lysine
44
What amino acids are non-essential
Alanine, Aspartic Acid, Glutamic Acid, Glutamine, Cysteine, Glycine, Tyrosine, Proline, Serine
45
The amino acids found in nature as well as in proteins are
L isomers
46
The –NH2 group is in a ________ position
horizontal
47
_______ and ________ possess two chiral centers
Isoleucine and Threonine
48
usually formed by an enzyme-facilitated reaction on a common amino acid after that amino acid has been incorporated into a protein structure
Uncommon Amino Acids
49
Derivative of 4 Lys residues
Desmosine
50
found in elastin
Isodesmosine
51
constituent of myosin
6-N-methyllysine
52
found in collagen
hydroxyproline and
hydroxylysine
53
found in prothrombin
𝛾-carboxyglutamate
54
Compounds like the basic structure of amino acids, but do not
occur in proteins
Non-Standard Amino Acids
55
Found in coenzyme A
β-alanine
56
found in bile acids
Taurine
57
intermediates in urea cycle
ornithine and citrulline
58
thyroid hormones synthesized from
tyrosine
thyroxine (T4) and tri-iodo thyronine (T3)
59
a neurotransmitter produced from
glutamic acid
𝛾-aminobutyric acid (GABA)
60
End-product of pyrimidine metabolism
β-amino isobutyric acid
61
intermediate in heme synthesis
δ-aminolevulinic acid (δ-ALA)
62
methyl donor formed from L-methionine
S-adenosyl methionine (SAM)
63
a precursor of melanin pigment
3,4-dihydroxyphenylalanine
(DOPA)
64
constituents of bacterial cell walls
D-glutamic acid and D-alanine
65
found in certain antibiotics, e.g., gramicidin-S, Actinomycin-D
D-amino acids
66
have been found in brain tissue
D-aspartate and D-serine
67
– Contains an essential dietary micronutrient- selenium) as a
constitutive component.
Selenocysteine
68
found in mammalian blood. It has an antioxidant function, and its concentration falls in selenium deficiency
Selenoprotein P
69
− 22nd amino acid
− used for biosynthesis of proteins in some methanogenic archaea and bacteria
Pyrrolysine (Pyl, O)
70
Some amino acids are converted to carbohydrates and are called as
glucogenic amino acids
71
forms hormones such as thyroid hormones (T3 and T4), epinephrine and
norepinephrine, and a pigment called
melanin
Tyrosine
72
can synthesize a vitamin called niacin Formed serotonin
Tryptophan
73
synthesize creatine
Glycine, arginine and methionine
74
help in synthesis of bile salts
Glycine and cysteine
75
Synthesize glutathione
Glutamate, cysteine, & glycine
76
Changes histamine on decarboxylation
Histidine
77
Is used for the synthesis of heme
Glycine
78
Pyrimidine uses these amino acids for their
synthesis
Aspartate & Glutamine
79
Purine synthesis
Glycine, aspartic acid, glutamine, & serine
80
In neutral solution, the –COOH group of an amino acid donates a proton to the –NH2 of the same amino acid. This is called an ________ reaction
internal acid–base reaction
81
– a molecule with positive and negative charges on the same molecule, but has no net charge
zwitterions
82
Substances that have a dual (acid-base) nature are _____ and often called ______
amphoteric, ampholytes
83
pH at which an amino acid exist primarily in its zwitterion form (net charge is zero)
Isoelectric point (pI)
84
True or False?
At isoelectric points, amino acids are attracted towards an applied electric field
because they carry net zero charge.
False, amino acids are NOT attracted towards an applied electric field
because they carry net zero charge
85
are composed of only a small number of
amino acids joined as peptide bonds
Peptides
86
made up of two amino acids
Dipeptides
87
made up of three amino acid
Tripeptides
88
refers to peptides with 10 to 20 amino acid residues
Oligopeptide
89
a long unbranched chain of amino acids
Polypeptide
90
True or False?
Under proper conditions, amino acids can bond together to produce an unbranched chain of amino acids
True
91
if an amino acid chain has 5 amino acids how many peptide bonds exist?
4 peptide bonds
92
The structure of peptides is represented beginning with the amino acid whose amino group is free
N-terminal end
93
The other end contains a free carboxyl
group and is the
C-terminal end
94
The amino acid at one end of amino
acid sequence has a free _____ group,
and the amino acid at the other end with
a free ______ group
H3N+, COO-
95
The individual amino acids within a peptide chain are called
amino acid residues
96
– best-known peptide hormones: oxytocin and vasopressin
– produced by the pituitary gland
– nonapeptide (nine amino acid residues) with six of the residues held in the form of a loop by a disulfide bond formed between two cysteine residues. Differ in the amino acid present in positions 3 and 8 of the peptide chain
Small peptide hormones
97
* Enkephalins are pentapeptide neurotransmitters produced by the brain and bind receptors within the brain
* help reduce pain
Small peptide neurotransmitters
98
Best-known enkephalins
1. Met-enkephalin: Tyr–Gly–Gly–Phe–Met
2. Leu-enkephalin: Tyr–Gly–Gly–Phe–Leu
99
The action of the prescription painkillers morphine and codeine is based on the actions of __________
enkephalins
100
Unusual structural feature – Glu is bonded to Cys through the side-chain carboxyl group
Small peptide antioxidants
101
− dipeptide sold under trade names Equal and Nutrasweet
− ~180x as sweet as sucrose
Aspartame (Asp-Phe)
102
ONE LETTER: A
THREE LETER: Ala
Alanine
103
ONE LETTER: R
THREE LETTER: Arg
Arginine
104
ONE LETTER: N
THREE LETTER: Asn
Asparagine
105
ONE LETTER: D
THREE LETTER: Asp
Aspartic acid
106
ONE LETTER: C
THREE LETTER: Cys
Cysteine
107
ONE LETTER: Q
THREE LETTER: Gln
Glutamine
108
ONE LETTER: E
THREE LETTER: Glu
Glutamic Acid
109
ONE LETTER: G
THREE LETTER: Gly
Glycine
110
ONE LETTER: H
THREE LETTER: His
Histidine
111
ONE LETTER: I
THREE LETTER: Ile
Isoleucine
112
ONE LETTER: L
THREE LETTER: Leu
Leucine
113
ONE LETTER: K
THREE LETTER: Lys
Lysine
114
ONE LETTER: M
THREE LETTER: Met
Methionine
115
ONE LETTER: F
THREE LETTER: Phe
Phenylalanine
116
ONE LETTER: P
THREE LETTER: Pro
Proline
117
ONE LETTER: S
THREE LETTER: Ser
Serine
118
ONE LETTER: T
THREE LETTER: Thr
Threonine
119
ONE LETTER: W
THREE LETTER: Typ
Tryptophan
120
ONE LETTER: Y
THREE LETTER: Tyr
Tyrosine
121
ONE LETTER: V
THREE LETTER: Val
Valine
122
ONE LETTER: O
THREE LETTER: Pyl
Pyrrolysine
123
ONE LETTER: U
THREE LETTER: Sec
Selenocysteine
124
ONE LETTER: B
THREE LETTER: Asx
Aspartic acid or Asparagine
125
ONE LETTER: Z
THREE LETTER: Glx
Glutamic acid or Glutamine
