Chapter 4 Flashcards
(109 cards)
1
Q
What are the 5 General structures of amino acids?
A
Amino group Carboxyl Group a- carbon hydrogen R group
2
Q
It is located in the center with the other four groups bonded to it
A
a-group
3
Q
It is the chiral center in all amino acids
A
a-carbon
4
Q
a group has four different bonded into it and it gives rise to two nonsuperimpossible mirror image forms which are?
A
Stereoisomers and Enatiomers
5
Q
a group has four different bonded into it and it gives rise to two nonsuperimpossible mirror image forms which are?
A
Stereoisomers and Enantiomers
6
Q
enantiomer display a special property called?
A
optical activity
7
Q
it is the ability to rotate the plane of polarization of plane-polarized light
A
optical activity
8
Q
what behavior have feature of clockwise rotation of incident light which displays D-configuration
A
Dextrorotatory behavior
9
Q
what behavior have a feature of counterclockwise rotation which displays L-configuration
A
Levorotatory behavior
10
Q
Amino acids that occur in protein
A
L-form
11
Q
Amino acids that occurs in nature, but they are not found in proteins
A
D form
12
Q
What is the most used classification of amino acids?
A
polarity and side chains
13
Q
what are the four types of amino acids based on the feature of the side chain?
A
nonpolar or hydrophobic amino acids
neutral (uncharged) but polar amino acids
acidic amino acids
basic amino acids
14
Q
this amino acids is critically important for the processes that drive protein chains to fold to their natural or functional series
A
nonpolar amino acids
15
Q
this non polar amino acids has a benzene ring and a secondary amine
A
proline
16
Q
phenylalanine and tryptophan are both?
A
aromatic
17
Q
its a sidechain that contains a sulfur atom in its hydrogen group
A
methionine
18
Q
sidechains that is just hydrocarbon group
A
alanine, valine, leucine, and isoleucine
19
Q
type of amino acids that have polar side chain that are uncharged at neutral pH
A
neutral but polar amino acids
20
Q
it can form hydrogen bonds with water and play as a variety of nucleophilic role in enzyme reactions
A
r group
21
Q
what amino acids that are usually more soluble in water than the nonpolar amino acids
A
neutral / polar amino acids
22
Q
the polar group is hydroxyl bonded to hydrocarbon groups
A
serine and threonine
23
Q
The hydroxyl group is bonded to an aromatic
hydrocarbon group, which is a phenol.
A
tyrosine
24
Q
Have amide groups that are derived from carboxyl
groups in their side chains.
A
Glutamine and asparagine
25
Have carboxyl groups in their side chains in addition to
the one present in all amino acids
acidic amino acids
26
Because of the presence of the _____ the side chain of acidic amino acids is negatively charged at neutral pH
carboxylate
27
Have basic side chains, and the side chain in all three is
positively charged at the neutral pH
basic amino acids
28
the side-chain amino group is
bonded to a hydrocarbon tail
lysine
29
the side-chain guanidino group is
also bonded to a hydrocarbon tail.
arginine
30
histidine has an ____ side chain
imidazole
31
what amino acids are important biological buffers?
histidine
32
An amide bond formed in a head-to-tail
fashion between the -COO– group of one
amino acid and the -NH+
3 group of another
amino acid
Peptide bond
33
The molecule formed by condensing two amino
acids
Dipeptide
34
The amino acid with a free -NH+
3 group
N-terminus
35
Amino acids without charged groups on their side
chains exist in neutral solution with no net charge.
Zwitterions
36
Biologically active proteins are polymers consisting of
amino acids linked by
covalent peptide bonds
37
The order in which the amino acids are covalently linked
together through the peptide bond
Primary stricture
38
One of the most striking examples of the importance of
primary structure is found in the hemoglobin associated
with
sickle-cell anemia
39
s is the
hydrogen-bonded arrangement of the polypeptide chain
backbone.
secondary structure
40
These structures tend to form in cooperative fashion and
involve substantial portions of the peptide chain
secondary structure
41
stabilized by hydrogen bonds parallel to the
helix axis within the backbone of a single
polypeptide chain
a-helix
42
Because these N-H and C-O groups are all
aligned along the helix axis, the helix itself has
a
substantial dipole moment
43
Counting from the N-terminal end, the C-O group of
each amino acid residue is hydrogen bonded to the N-H
group of the amino acid _________ from it in the
covalently bonded sequence
four residues away
44
If the peptide chains run in the same direction, a ______ is formed
parallel pleated sheet
45
When the peptide chains run in opposite directions,
an _______is formed
antiparallel pleated sheet
46
are typically large structures; those
composed of fewer than five strands are rare
parallel sheets
47
are usually arranged with
all their hydrophobic residues on one side of the
sheet
antiparallel sheet
48
of a protein is the three dimensional arrangement of all the atoms in a single
polypeptide.
tertiary structure
49
subtle changes in structure at
one site of the protein molecule may cause dramatic
changes in properties at a distant site is known as
allosteric modulation
50
what can be unfolded and
refolded without the assistance of such chaperones
proteins in dilute solutions
51
contain polypeptide chains organized
approximately in parallel along a single axis, producing
long fibers or large sheets
fibrous proteins
52
proteins that are mechanically strong and resistant to solubilization in water
fibrous proteins
53
The structure of the α-keratin is dominated by?
a-helical segments
54
is a rigid, inextensible fibrous protein that is
composed of three intertwined polypeptide chains and
is a principal constituent of connective tissue in
animals, including tendons, cartilage, bones, teeth,
skin, and blood vessels.
collagen
55
are named for their approximately
spherical shapes and are the most abundant proteins in
nature
globular proteins
56
globular proteins contains mostly of
a-helices and b-sheets
57
what side chains lie on the surface
of the globular proteins exposed to the water
hydrophilic amino acids
58
proteins composed of how many amino acids
250 amino acids
59
These are compact, folded protein structures that are
usually stable by themselves in aqueous solution.
Globular proteins
60
are found in association with the
various membrane systems of cells.
membrane proteins
61
are usually bound to the charged
head groups of the lipid bilayer by polar interactions,
electrostatic interactions, or both
Peripheral proteins
62
are insoluble in aqueous solutions
but can be solubilized in detergents
integral proteins
63
help move substances
in and out of the cell, and receptor proteins are
important in the transfer of extracellular signals
transport proteins
64
membrane proteins responsible for aerobic
oxidation reactions are tightly bound to
mitochondrial membrane
65
primary structure proteins arises from the?
covalent bonds
66
secondary, tertiary, and quaternary structures are maintained by?
weak or non covalent bonds
67
tends to disrupt hydrophobic interactions and electrostatic interactions
SDS
68
form hydrogen
bonds with the protein that are stronger than those
within the protein itself.
urea and guanidine hydrochloride
69
is
often used to reduce disulfide bridges to two sulfhydryl
groups.
b - mercaptoethanol
70
it is a dramatic
demonstration of the relationship between the primary
structure of the protein and the forces that determine
the tertiary structure
denaturation and refolding
71
is written in linear form, using the
ribonucleotides that compose mRNA molecules as
letters
genetic code
72
is derived from the
complementary nucleotide bases in the DNA template
strand
ribonucleotide sequence
73
a genetic code is a ____ in which sequence of three bases is needed to specify one amino acid
triplet code
74
what rule states All 64 codons have been assigned meaning, with 61 of
them coding for amino acids and the remaining 3
serving as the termination signals, also called
nonsense codons
wobble rules
75
The bases that are common to several codons are
usually the first and second bases, with more room for
variation in the third base, which is called the
wobble base
76
indicate that a first-base anticodon U
could recognize either an A or G in the codon third base position, and a first-base anticodon G might
recognize either U or C in the third-base position of the
codon
wobble rules
77
it is the biological polymerization
of amino acids into polypeptide chains
translation of mRNA
78
translation of mRNA requires?
mRNA, tRNA, and a ribosome
79
holds amino acids
in proximity to each other so that a peptide bond can be
formed
Hydrogen bonding of tRNA to mRNA
80
it is a complex molecular machine
and it consists of two subunits, one large and one small.
Both subunits consist of one or more molecules of rRNA
and ribosomal proteins.
bacterial ribosome
81
, two-thirds of the mass of the ribosome is
made up of?
rRNA
82
The subunit and rRNA components are most easily
isolated and characterized on the basis of their
sedimentation behavior in?
sucrose gradient
83
The velocity
of sedimentation has been standardized in units
svedbergs (S)
84
he large subunit in prokaryotes consists of a
23S rRNA molecule, a 5S rRNA molecule, and 34 ribosomal
proteins
85
he small subunit consists of a
16S rRNA
component and 21 ribosomal proteins
86
the large subunit in eukaryotes
consists of a
28S rRNA, a 5.8S rRNA, an 5S rRNA, and
46 ribosomal proteins
87
the small subunit consists of
18S rRNA and 33 ribosomal proteins
88
what subunit mediates the interactions between
mRNA and tRNA?
small subunit
89
what subunit catalyzes peptide bond formation
large subunit
90
are formed by 16S rRNA, in
which just under half of the sequence is base paired
four general domains
91
serves as
the decoding center is composed only of 16S rRNA. 16S
rRNA molecules fold into characteristic secondary
structures as a consequence of intramolecular base pairing interactions
the central domain of the 30s
92
catalytic center and located at the bottom of a deep cleft
peptidyl transferase
93
the two subunits come
together to form the 70S (80S in eukaryotes) ribosome
and launch the elongation cycle
during translation initiation
94
The tRNA is composed of
75 to 90 nucleotides
95
is the linear sequence of bases in the
RNA
Primary structure
96
is the stem-loops structure derived
from the base pairing between different regions of the
sequence
Secondary structure
97
is the overall three-dimensional shape
of the molecule
tertiary structure
98
The first, seen at the top of the diagram, is the
acceptor stem
99
The acceptor arm has both
50 and 30 ends of the tRNA
100
On the left is the _____________. This is
named for the modified uracil bases in this region
dihydrouracil loop
101
This region base pairs with an mRNA codon and therefore allows decoding
of the mRNA.
anticodon loop
102
The region between the anticodon loop and T loop is
called the
variable loop
103
what are the two steps of the translation?
generate supply of aminoacyl-tRNA
dissociation of ribosomes
104
is the code by which each
aminoacyl-tRNA synthetase matches up its amino acid
with tRNAs that can interact with codons specifying its
amino acid
second genetic code
105
The aminoacyl-tRNA synthetases display an overall error
rate of about?
one in 10,000
106
is the ubiquitin-activating enzyme. It becomes
attached via a thioester bond to the C-terminal Gly
residue of ubiquitin.
E1
107
he ubiquitin-carrier protein. In protein
degradation, E2-S-ubiquitin transfers ubiquitin to
free amino groups on proteins selected by E3, the
ubiquitin-protein ligases.
E2
108
plays a central role in recognizing
and selecting proteins for degradation.
E3
109
Highly conserved proteins and are covalently
ligated to target proteins by a three-enzyme
conjugating system
Small ubiquitin like protein modifiers
