Revision Flashcards
(23 cards)
what do leucine, isoleucine and valine have in common?
A) they are positively charged at neutral pH
B) they are negatively charged at neutral pH
C) they are aromatic
D) they have nonpolar aliphatic side chains
E) they contain sulfur
F) they have an amide group in their side chain
G) they have a hydroxyl group in their side chain
D) they have nonpolar aliphatic side chains
Which of the following amino acid residues would most likely be
buried in the interior of a water-soluble, globular protein?
A) aspartate
B) glutamate
C) phenylalanine
D) lysine
C) phenylalanine
How many of the 20 common amino acids have rings in their structures?
A) 2
B) 3
C) 4
D) 5
E) 6
D) 5
Which statement is correct?
A) Proteins contain only D amino acids
B) Proteins contain only L amino acids
C) Proteins contain both D and L amino acids
D) None of the above
B) Proteins contain only L amino acids
What is the definition of the isoelectric point?
A) pH at which a molecule is fully protonated
B) pH at which the net charge of a molecule is zero
C) pH at which the concentration of an acid
and its conjugate base is the same
D) pH at which a molecule is fully deprotonated
B) pH at which the net charge of a molecule is zero
What is the net charge of glycine at pH 1?
A) -2
B) -1
C) 0
D) +1
E) +2
D) +1
Which of the following amino acids has a pKR?
A) Proline
B) Aspartic acid
C) Valine
D) Leucine
B) Aspartic acid
Below are the pKR values of several amino acids. Which amino acid
has the side chain with the strongest base?
A) histidine (6.0)
B) lysine (10.5)
C) arginine (12.5)
D) The strength of a base cannot be determined from the pKR value.
C) arginine (12.5)
Protein folding to a native conformation is highly dependent upon all of the following, except:
A) rotation about the alpha-carbon, carbon bond in the backbone.
B) the polar character of sequences of amino acids.
C) the relative size of amino acid R-groups.
D) the rotation about the peptide bond.
E) the rotation about the alpha-carbon,
nitrogen bond
D) the rotation about the peptide bond.
In the alpha helix the hydrogen bonds:
A) are roughly parallel to the axis of the helix
B) are roughly perpendicular to the axis of the helix.
C) occur mainly between electronegative atoms of the R groups.
D) occur only between some of the amino acids of the helix.
E) occur only near the amino and carboxyl termini of the helix.
A) are roughly parallel to the axis of the helix
Which of the following best describes the arrangement of amino acid
side chains in an alpha helix?
A) The side chains point outward away from the helical axis.
B) The side chains point inward toward the centre of the helix.
C) The side chains point toward the N-terminal end of the helix.
D) The side chains point toward the C-terminal end of the helix.
E) The side chains point toward the nearest beta sheet.
A) The side chains point outward away from the helical axis.
Which gel material is used for DNA gel electrophoresis?
Agarose for large DNA fragments
Polyacrylamide for small DNA fragments
Which gel material is used for protein gel electrophoresis?
Polyacrylamide gel electrophoresis (PAGE)
What is a monosaccharide?
The simplest carbohydrates, contain a carbonyl group, each carbon usually bound to a hydroxyl group
Important pentoses?
Ribose and deoxyribose
Important hexoses?
Glucose, fructose and galactose
How does a nucleotide differ from a nucleoside?
A) A nucleotide is a nucleoside with a phosphate ester-linked to the sugar.
B) Nucleosides are found in DNA, whereas nucleotides are found in RNA.
C) Nucleosides contain only deoxyribose sugars.
D) Purines are only found in nucleotides.
E) None of the answers is correct
A) A nucleotide is a nucleoside with a phosphate ester-linked to the sugar.
The difference in RNA bases compared to DNA bases is
A) RNA contains A instead of T.
B) RNA contains A instead of U.
C) RNA contains U instead of G.
D) RNA contains U instead of T.
E) None of the answers is correct.
D) RNA contains U instead of T.
The difference between a ribonucleotide and a deoxyribonucleotide is:
A) a deoxyribonucleotide has an —H instead of an —OH at C-2.
B) a deoxyribonucleotide has an —H instead of an —OH at C-3.
C) a ribonucleotide has an extra —OH at C-4.
D) a ribonucleotide has more structural flexibility than deoxyribonucleotide.
E) a ribonucleotide is a pyranose, deoxyribonucleotide is a furanose.
A) a deoxyribonucleotide has an —H instead of an —OH at C-2.
The feature(s) of DNA deduced by Watson and Crick included
A) The bases are nearly perpendicular to the axis.
B) The pyrimidine and purine bases lie on the inside of the helix.
C) Two antiparallel polynucleotide chains coiled in a helix around a
common axis.
D) All of the answers are correct.
E) None of the answers is correct.
D) All of the answers are correct.
In which direction does mRNA synthesis by RNA polymerase occur?
A) 3’ → 5’
B) 5’ → 3’
C) A → U
D) C → N
E) N → C
B) 5’ → 3’
The low incidence of protein or lipid flip-flop in a membrane preserves
A) membrane fluidity.
B) membrane melting temperatures.
C) membrane asymmetry.
D) membrane fluidity and membrane melting temperatures.
E) All of the answers are correct.
C) membrane asymmetry.
Which of the following membranes would be the most fluid?
A) a bilayer made of lipids with polyunsaturated 18 carbon-fatty acids
B) a bilayer made of lipids with saturated 18 carbon-fatty acids
C) a bilayer made of lipids with saturated 16 carbon-fatty acids
D) a bilayer made of lipids with polyunsaturated 16 carbon-fatty acids
E) All of the above are equivalent in fluidity.
D) a bilayer made of lipids with polyunsaturated 16 carbon-fatty acids
