AMINO ACIDS Flashcards
1
Q
from the Greek word proteios meaning “first”, is
a complex biomolecule, which does most of the work in
cells.
A
Proteins
2
Q
All proteins in humans are large molecules made up from ________________
A
20 different amino acids
3
Q
contains about 9,000 different kinds
of proteins
A
typical human cell
4
Q
contains about 100,000
different proteins.
A
human body
5
Q
FUNCTIONS OF PROTEIN
A
- Provide structure in membranes.
- Build cartilage and connective tissue.
- Transport oxygen in blood and muscle.
- Direct biological reactions as enzymes.
- Defends the body against infection.
- Controls metabolic processes as hormones.
- Can be used as a source of energy.
6
Q
building blocks of protein.
A
amino acids
7
Q
organic compounds, consisting of socalled elements of life
A
Amino acids
8
Q
Amino acids’ components
A
carbon, hydrogen, oxygen, and nitrogen along with a variable side chain or R-group
9
Q
what renders chemical
distinctiveness to the individual amino acid molecule.
A
variable side chain or R-group
10
Q
a molecule that can be
bonded to other identical molecules to form a polymer.
A
monomers
11
Q
are amino acids monomers?
A
yes
12
Q
Amino acids are chained or joined together by amide (C –
N bonds) also known as ____.
A
peptide linkages
13
Q
What are the alpha carbon of the amino acids
A
COO- group
14
Q
Attached to the alpha carbon are four different groups:
A
amino group (- NH3+ or ammonium cation), a
carboxylate anion (COO-
), hydrogen, and an R-group
15
Q
Proteins account for __% of the dry weight of the
human body
A
50
16
Q
Unlike lipids and carbohydrates, proteins are not
stored,
A
they must be consumed daily.
17
Q
Amino acids contain two functional groups
A
amino
group (NH2) and a carboxyl group (COOH).
18
Q
simplest amino acid, where R = H.
A
glycine
19
Q
called the side chain, determines the
identity of the amino acid
A
R-group
20
Q
If R = an additional COOH group
A
acidic amino
acid.
21
Q
If R = a basic N atom
A
basic amino acid
22
Q
Since amino acids contain a base (NH2) and an acid
(COOH), a proton transfers from the acid to the base to
form a
A
zwitterion.
23
Q
NEUTRAL COMMON AMINO ACIDS
A
Alanine
Asparagine
Cysteine
Glutamine
Isoleucine
Leucine
Methionine
Phenylalanine
Proline
Serine
Threonine
Valine
Tryptophan
Tyrosine
24
Q
Acidic Amino Acids
A
Aspartic acid
Glutamic acid
25
Basic Amino acids
Arganine
Histidine
Lysine
26
an atom that has four different groups bonded to it such a
manner that it has a non-superimposable four image
chirality center
27
ALIPHATIC NON-POLAR SIDE CHAINS
Alanine
Glycine
Isoleucine
Leucine
Valine
28
AROMATIC SIDE CHAINS
Phenylalanine
Tyrosine
Tryptophan
29
HYDROXYL SIDE CHAINS
Serine
Threonine
30
a functional group with one
hydrogen and one oxygen atom.
Hydroxyl groups (-OH)
31
Sulfur-containing Side Chains
Cysteine
Methionine
32
Acidic Amino Acids
Aspartate
Glutamate
33
Amidic Side Chains
Asparagine
Glutamine
34
Basic Amino Acids
Arginine
Histidine
Lysine
35
Imino Acid
Proline
36
NON-POLAR AMINO ACIDS
1. Alanine Ala A
2. Isoleucine Ile I
3. Leucine Leu L
4. Methionine Met M
5. Phenylalanine Phe F
6. Proline Pro P
7. Tryptophan Trp W
8. Tyrosine Tyr Y
9. Valine Val V
37
POLAR AMINO ACIDS
10. Asparagine Asn N
11. Cysteine Cys C
12. Glutamine Gln Q
13. Glycine Gly G
14. Serine Ser S
15. Threonine Thr T
38
ACIDIC AMINO ACIDS
16. Aspartic acid Asp D
17. Glutamic acid Glu E
39
BASIC AMINO ACIDS
18. Arginine Arg R
19. Histidine His H
20. Lysine Lys K
40
essential to the
normal functioning of the human body.
Since the body is not capable of
synthesizing them, they must be supplied in
our diets.
standard amino acid needed for protein synthesis that must be obtained from dietary sources because the human body cannot synthesize it in adequate amounts from other substances.
Essential amino acids
41
ESSENTIAL AMINO ACIDS FOR
HUMANS
1. Phenylalanine 9. Histidine*
2. Valine 10. Arginine*
3. Tryptophan
4. Threonine
5. Isoleucine
6. Methionine
*relatively essential
7. Leucine PVT TIM HALL
8. Lysine
42
supplies all the
essential amino acids; usually from animal
sources (except gelatin - absence of
tryptophan HC Test)
complete protein
43
deficient in one or
more essential amino acids; usually from
plant sources.
incomplete protein
44
HYDROLYSIS OF PROTEIN:
Protein
Protein <=======> proteoses <======>
H2O H2O
peptones <======> polypeptides <=======>
H2O H2O
tripeptides <======> dipeptides <======>
amino acids
45
a protein that contains all of the essential amino acids in the same relative amounts in which the body needs them. may or may not contain all of the nonessential amino acids.
complete dietary protein
46
protein that does not contain adequate amounts, relative to the body’s needs, of one or more of the essential amino acids.
incomplete dietary protein
47
an essential amino acid that is missing, or present in inadequate amounts, in an incomplete dietary protein.
limiting amino acid
48
Protein from animal sources
a complete dietary protein.
49
one common incomplete dietary protein that comes from animal sources.
gelatin, a protein in which tryptophan is the limiting amino acid.
50
incomplete dietary protein example
Protein from plant sources
lysine (wheat, rice, oats, and corn)
methionine (beans and peas)
tryptophan (corn and beans)
51
two or more incomplete dietary proteins that, when combined, provide an adequate amount of all essential amino acids relative to the body’s needs
Complementary dietary proteins
52
Amino acids are _____when they can
react either as an acid or a base.
amphoteric
53
An amino acid exists as a neutrally charged
zwitterion (dipolar) at a certain pH,
isoelectric pH
54
pH at which there is no migration
toward either electrode is called the
_____;
✓pH when an amino acid in solution has
equal + and – charges;
✓electrically neutral;
✓does not migrate toward either the positive
or negative electrode when placed in an
electrolytic cell.
Isoelectric Point
55
pI of Amino Acids
Alanine 6.00
Leucine 5.98
Arginine 10.76
Lysine 9.74
Asparagine 5.41
Methionine 5.74
Aspartic Acid 2.77 Phenylalanine 5.48
Cysteine 5.07
Proline 6.30
Glutamic Acid 3.22
Serine 5.58
Glutamine 5.65
Threonine 5.60
Glycine 5.97
Tryptophan 5.89
Histidine 7.59
Tyrosine 5.66
Isoleucine 6.02
Valine 5.96 5
56
When the pH < isoelectric pH, the carboxylate
anion gains a proton, and the amino acid has a
net positive charge.
57
When the pH > isoelectric pH, the ammonium
cation loses a proton, and the amino acid has a
net negative charge.
58
a short chain of amino acids.
are generally considered to be short chains of two or more amino acids.
peptide
59
The amino acids in a peptide are connected to one another in a sequence by bonds called
peptide bonds
60
Proteins can be digested by enzymes (other proteins) into
peptide fragments
61
Peptides and proteins are formed when amino acids are joined together by _______.
amide bonds
62
has two amino acids joined together
by one amide bond.
dipeptide
63
The amide bond is called
peptide bond.
64
has three amino acids joined together
by one amide bond
tripeptide
65
have many amino acids, while
proteins have more than 40 amino acids.
Polypeptides
66
The amino acid with the free –NH3+ group is the
N-terminal amino acid and is written on the
left
67
The amino acid with the free –COO− group is the
C-terminal amino acid and it written on the
right.
68
pentapeptides made in the brain,
act as pain killers and sedatives by binding
to pain receptors.
Enkephalins
69
Addictive drugs that bind to these
same pain receptors, thus producing a similar
physiological response, though longer lasting.
morphine and heroin
70
Enkephalins belong to the family of polypeptides
called ______
endorphins
71
which are known for their
pain reducing and mood enhancing effects.
endorphins
72
cyclic nonapeptide
hormones, which have identical sequences
except for two amino acids.
Oxytocin and vasopressin
73
stimulates the contraction of uterine
muscles, and signals for milk production; it is
often used to induce labor.
Oxytocin
74
antidiuretic hormone (ADH) targets
the kidneys and helps to limit urine production to
keep body fluids up during dehydration.
Vasopressin
75
To maximize hydrogen bonding with water, the
nonpolar side chains are stabilized _______________ in the interior of the structure.
London
dispersion forces
76
form covalent bonds that
stabilize the tertiary structure.
Disulfide bonds
77
the 3D shape adopted by
the entire peptide chain.
tertiary structure
78
is the
shape adopted when two or more folded poly-
peptide chains come together into one complex.
quaternary structure of the protein
79
consists of two separate polypeptide chains
linked by intermolecular disulfide bonds
Insulin
80
consists of four subunits held
together by intermolecular forces into a compact
3D shape.
Hemoglobin
81
composed of long linear
polypeptide chains that are bundled together to
form rods or sheets.
insoluble in water and serve
structural roles.
Fibrous proteins
82
coiled into compact shapes
that are water soluble.
Enzymes and transport proteins are ______.
*Globular proteins
83
he proteins found in hair, hooves,
nails, skin, and wool
They are made of two mainly a-helix chains coiled
around each other in a superhelix.
-Keratins
84
requires three chains in a superhelix.
Collagen
85
helps stabilize the chains, and, when
missing, poorly formed collagen fibers result.
Vitamin C
86
Both _____ and _____ are globular
and conjugated proteins, meaning they contain
both a protein and non-protein component.
hemoglobin and myoglobin
87
non-protein unit of hemoglobin and myoglobin, an organic complex surrounding a Fe^+2 ion
heme
88
poisonous because it
binds 200 times more strongly to the Fe+2
than does O2.
Carbon monoxide (CO)
89
disease where a single
amino acid is different in two of the subunits
of hemoglobin.
*Red blood cells containing these mutated
hemoglobin units become elongated and crescent
(sickle) shaped.
*These red blood cells will rupture capillaries,
causing pain and inflammation, leading to organ
damage, and eventually a painful death.
Sickle cell anemia
90
inhibits the enzyme that forms cell
walls of bacteria, destroying the bacterium.
Penicillin
91
causes
blood vessels to narrow, increasing blood pressure.
ACE (angiotensin-converting enzyme)
92
are given to those with high blood
pressure to prevent ACE’s synthesis from it’s
zymogen.
ACE inhibitors
93
an essential enzyme that allows
the virus to make copies of itself.
HIV protease
94
interfere with this copying,
decreasing the virus population in the patient.
HIV protease inhibitors
95
involves the disruption and possible destruction of both the secondary and tertiary structures.
disrupts the normal alpha-helix and beta sheets in a protein and uncoils it into a random shape
Denaturation of proteins
96
The most common observation in the denaturation process is the precipitation or coagulation of the protein.
Heat - increases the kinetic energy and causes the molecules to vibrate so rapidly and violently that the bonds are disrupted.
Alcohol (Disrupts Hydrogen Bonding) - disrupting the side chain intramolecular hydrogen bonding
Acids and Bases Disrupt Salt Bridges - disrupt salt bridges held together by ionic charges
- A type of double replacement reaction occurs where the positive and negative ions in the salt change partner with the positive and negative ions in the new acid or base added.
Heavy Metal Salts - usually leads to an insoluble metal protein salt.
Reducing Agents Disrupt Disulfide Bonds
