Chem 221 - Biochemistry for Science Majors » Fall 2021 » L5 3D Structure of Proteins Part 1 of 2
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Question #1
Gobular proteins
A.
are roughly spherical in shape
B.
All of these are correct
C.
have their hydrophilic side chains are on the outside, exposed to the solvent, water.
D.
have their hydrophobic amino acid side chains are in the interior of the molecule
E.
are water soluble
Question #2
The linear arrangement of amino acids in a protein is called primary structure
A.
TRUE
B.
FALSE
Question #3
The sequence of amino acids in a protein is listed from the C-terminus to the N-terminus.
A.
TRUE
B.
FALSE
Question #4
Proteins channels within membranes, have hydrophobic amino acid side chains oriented outward.
A.
FALSE
B.
TRUE
Question #5
Membrane proteins characteristically have a larger number of hydrophilic amino acids than cytosolic proteins.
A.
FALSE
B.
TRUE
Question #6
Sickle cell anemia is an important example of conservative mutation.
A.
TRUE
B.
FALSE
Question #7
At physiological pH, the N-terminal and C-terminal residues can form salt bridges.
A.
FALSE
B.
TRUE
Question #8
During the formation of the peptide bond which of the following takes place?
A.
Hydroxyl group is lost from its carboxyl group of one amino acid and a hydrogen atom is lost from its amino group of another amino acid
B.
Hydroxyl group is lost from its carboxyl group of one amino acid and a hydroxyl group is lost from its amino group of another amino acid
C.
Hydrogen atom is lost from its carboxyl group of one amino acid and a hydroxyl group is lost from its amino group of another amino acid
D.
Hydrogen atom is lost from its carboxyl group of one amino acid and a hydrogen atom is lost from its amino group of another amino acid
Question #9
Peptide bond is a _________
A.
Metallic bond
B.
Covalent bond
C.
Hydrogen bond
D.
ionic bond
Question #10
A tripeptide has _________
A.
3 amino acids and 4 peptide bonds
B.
3 amino acids and 3 peptide bonds
C.
3 amino acids and 1 peptide bond
D.
3 amino acids and 2 peptide bonds
Question #11
The peptide bond in proteins is
A.
nonpolar, and fixed in a trans conformation
B.
nonpolar, but rotates to three preferred dihedral angles.
C.
not cleavable by hydrolysis.
D.
planar, and usually found in a trans configuration.
E.
planar, but rotates to three preferred dihedral angles.
Question #12
The resonance structures that can be drawn for the peptide bond indicate that the peptide bond
A.
still isn't completely understood by chemists.
B.
is weaker than an ordinary single bond.
C.
has partial double bond character.
Question #13
How many water molecules are lost from the condensation of 100 amino acids into a polypeptide?
A.
101
B.
99
C.
100
D.
98
E.
102
Question #14
Amino acids are connected via __________ bonds, which occur between the carboxyl group of one amino acid and the amino group of another.
A.
double
B.
amino
C.
hydrogen
D.
ionic
E.
peptide
Question #15
Condensation of 3 amino acids
A.
requires 2 molecules of water
B.
releases 2 molecules of water
C.
releases 3 molecules of water
Question #16
In how many different ways can the amino acids leucine, glutamate, and glycine be arranged?
A.
2
B.
3
C.
6
D.
4
E.
5
Question #17
What accounts for peptide bond planarity within a polypeptide?
A.
Hydrogen bonding between amino acid side chains and water
B.
The fully double bonded peptide bond
C.
Electronegativity differences between nitrogen and carbon
D.
Partial double bond character of the peptide bond
E.
The peptide bond is not planar, it can actually rotate relatively freely
Question #18
What does N-terminus refer to?
A.
The end of a protein with a free carboxylic acid group
B.
The end of a protein with a free amine group
C.
A protein chain
D.
The first amino acid with the abbreviation 'N' in the protein
Question #19
Which of the following statements is true about protein structure?
A.
A protein’s function depends on its spatial conformation
B.
pH does not change the protein conformation
C.
All proteins have a quaternary structure
D.
Disulfide bridges primarily maintain secondary structures, as opposed to tertiary
Question #20
The six atoms of the peptide group lie in a single plane and the configuration around the peptide bond is cis.
A.
FALSE
B.
TRUE
Question #21
Sickle cell anemia is an example of a genetic disease due to a problem with
A.
the primary structure of the myoglobin protein
B.
the secondary structure of a protein
C.
the function of all proteins in an organism
D.
the primary structure of the hemoglobin protein
Question #22
In the peptide Ser-Cys-Glu-Ala, the C-terminal end is ________.
A.
cysteine
B.
glutamic acid
C.
alanine
D.
glycine
Question #23
Uncharged side chains may experience ionic interactions in a protein structure.
A.
TRUE
B.
FALSE
Question #24
N-terminal and C-terminals may experience the formation of salt bridges
A.
FALSE
B.
TRUE
Question #25
In a soluble protein that resides in the cytoplasm, where is the majority of the nonpolar amino acids found in its three-dimensional structure?
A.
Randomly interspersed throughout to protein
B.
Localized to the C-terminus of the protein
C.
Buried in the center of the protein
D.
Localized to the N-terminus of the protein
E.
On the surface of the protein
Question #26
The formation of a tetrapeptide.
A.
Requires 3 water molecules
B.
Releases 4 water molecules
C.
Requires 4 water molecules
D.
Releases 3 water molecules
Question #27
The ability of a particular protein to carry out its function is determined by its overall three-dimensional shape, or conformation.
A.
FALSE
B.
TRUE
Question #28
In the peptide Ala-Try-Gly-Phe, the N-terminal amino acid is ________.
A.
alanine
B.
phenylalanine
C.
tryptophan
D.
aspartic acid
E.
glycine
Question #29
If, in a protein there is a change of an amino acid for another one, for instance a leucine is changed for lysine, the function of the protein most likely
A.
will be affected
B.
won't be affected
Question #30
A peptide bond is formed by hydrolysis reaction between the carboxyl group of one amino acid and the amino group of another.
A.
TRUE
B.
FALSE
Question #31
Where in a globular protein is the amino acid valine likely to be located?
A.
The hydrophilic exterior
B.
The hydrophobic interior
C.
The hydrophilic interior
D.
The hydrophobic exterior
Question #32
Which proteins are generally water-soluble?
A.
Globular proteins
B.
Both globular fibrous proteins
C.
Neither globular nor fibrous proteins
D.
Fibrous proteins
Question #33
To hydrolyze a pentapeptide you need
A.
4 molecules of water
B.
5 molecules of water
C.
2 molecules of water
D.
3 molecules of water
Question #34
A peptide bond is
A.
an amide bond
B.
a covalent ether bond
C.
a covalent bond
D.
a covalent amide bond
E.
an ether bond
Question #35
The peptide bond of proteins resembles the bond found in
A.
alkenes
B.
hydrocarbons
C.
alkanes
D.
alkynes
Question #36
What type of interaction would occur between glutamic acid and lysine?
A.
Ionic
B.
Hydrophobic
C.
disulfide
D.
hydrogen bonding
Question #37
A.
hydrogen bonding
B.
peptide bonds
C.
Ionic
D.
Hydrophobic
Question #38
Which of the following best describes the quaternary structure of a protein?
A.
The four parts of a protein's amino acid sequence
B.
The sequence of nucleic acids
C.
The layout of alpha-helices and beta-sheets
D.
How the polypeptide chains arrange in space
E.
A polypeptide chain 3-D structure
Question #39
A protein's primary structure is determined by which of the following?
A.
R-group interactions
B.
Alpha-helices
C.
The hydrophobic effect
D.
The linear sequence of specific amino acids
E.
Beta-pleated sheets
Question #40
Where, in a globular protein, is the amino acid glutamine likely to be located?
A.
The hydrophilic exterior
B.
The hydrophilic interior
C.
The hydrophobic exterior
D.
The hydrophobic interior
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