MCB 250 Pre-Lecture Questions With
Complete Solutions
Weak non-covalent bonds make a major contribution to all of the following
EXCEPT:
A. Protein:DNA interactions
B. Holding together two chains of the DNA double helix
C. Protein:protein interactions
D. Peptide bonds that link amino acids within a protein
E. Three-dimensional structure of proteins - ANSWER Peptide bonds that link
amino acids within a protein
Which of the following statements is true of van der Waals bonds?
A. Require a hydrogen donor and a hydrogen acceptor
B. Only occur between electrically charged molecules
C. Only occur in aqueous solutions
D. Can occur between any two closely spaced atoms
E. A single van der Waals bond can hold two molecules together stably at room
temperature - ANSWER Can occur between any two closely spaced atoms
Which one of the following statements is true of hydrogen bonds?
A. A hydrogen nucleus (H+) is physically transferred from the donor molecule to
the acceptor molecule
B. In cells, the most biologically significant hydrogen bonds involve O and/or N
atoms
C. Account for the crystalline structure of ice, but have little influence on the
chemical properties of liquid water
D. Can occur between polar or nonpolar molecules
E. Are nondirectional, i.e. bond strength does not depend on angle - ANSWER In
cells, the most biologically significant hydrogen bonds involve O and/or N atoms
Which one of the following statements is true of 'hydrophobic bonds'?
A. Result from the electrical attraction of polar molecules
B. Do not involve van der Waals bonds
C. Result in the destruction of water by hydrolysis
D. Occur in aqueous solutions from the tendency of water to exclude nonpolar
groups
, E. Are equally strong in aqueous and non-aqueous solutions - ANSWER Occur in
aqueous solutions from the tendency of water to exclude nonpolar groups
In a linear DNA molecule, the two ends of a single strand are designated as
A. 5' and 3'
B. A and T
C. pyrimidine and purine
D. N and C
E. phosphate and sugar - ANSWER 5' and 3'
Which of the following statements is NOT correct?
A. In the double helix, complementary base pairs are stabilized by hydrogen
bonds
B. Pyrimidines have two rings; purines have one
C. The radius of the double helix is relatively constant because A-T and C-G base
pairs are the same length
D. The bases of DNA are aromatic rings containing both carbon and nitrogen
atoms
E. The ratio of A-T to G-C base pairs varies in different organisms. - ANSWER
Pyrimidines have two rings; purines have one
In 1928, Frederic Griffith showed that
A. The relative content of the four bases in DNA differed between organisms, but
the amount of G is always equal to C and the amount of A is always equal toT
B. The bacteriophage T2 introduces DNA, not protein, into the bacterium it
infects
C. DNA replication is semiconservative
D. Different alleles of the same gene can be either dominant or recessive in their
influence on phenotype
E. A chemical derived from dead bacteria can produce heritable changes in the
traits of living cells - ANSWER A chemical derived from dead bacteria can
produce heritable changes in the traits of living cells
In 1953, James Watson and Francis Crick accurately predicted the structure of
DNA. They based their prediction on experimental data obtained by which
technique?
A. Stoichiometry of elements
B. DNA sequence analysis
C. Gel electrophoresis
D. Electron microscopy
E. X-ray diffraction - ANSWER X-ray diffraction
Complete Solutions
Weak non-covalent bonds make a major contribution to all of the following
EXCEPT:
A. Protein:DNA interactions
B. Holding together two chains of the DNA double helix
C. Protein:protein interactions
D. Peptide bonds that link amino acids within a protein
E. Three-dimensional structure of proteins - ANSWER Peptide bonds that link
amino acids within a protein
Which of the following statements is true of van der Waals bonds?
A. Require a hydrogen donor and a hydrogen acceptor
B. Only occur between electrically charged molecules
C. Only occur in aqueous solutions
D. Can occur between any two closely spaced atoms
E. A single van der Waals bond can hold two molecules together stably at room
temperature - ANSWER Can occur between any two closely spaced atoms
Which one of the following statements is true of hydrogen bonds?
A. A hydrogen nucleus (H+) is physically transferred from the donor molecule to
the acceptor molecule
B. In cells, the most biologically significant hydrogen bonds involve O and/or N
atoms
C. Account for the crystalline structure of ice, but have little influence on the
chemical properties of liquid water
D. Can occur between polar or nonpolar molecules
E. Are nondirectional, i.e. bond strength does not depend on angle - ANSWER In
cells, the most biologically significant hydrogen bonds involve O and/or N atoms
Which one of the following statements is true of 'hydrophobic bonds'?
A. Result from the electrical attraction of polar molecules
B. Do not involve van der Waals bonds
C. Result in the destruction of water by hydrolysis
D. Occur in aqueous solutions from the tendency of water to exclude nonpolar
groups
, E. Are equally strong in aqueous and non-aqueous solutions - ANSWER Occur in
aqueous solutions from the tendency of water to exclude nonpolar groups
In a linear DNA molecule, the two ends of a single strand are designated as
A. 5' and 3'
B. A and T
C. pyrimidine and purine
D. N and C
E. phosphate and sugar - ANSWER 5' and 3'
Which of the following statements is NOT correct?
A. In the double helix, complementary base pairs are stabilized by hydrogen
bonds
B. Pyrimidines have two rings; purines have one
C. The radius of the double helix is relatively constant because A-T and C-G base
pairs are the same length
D. The bases of DNA are aromatic rings containing both carbon and nitrogen
atoms
E. The ratio of A-T to G-C base pairs varies in different organisms. - ANSWER
Pyrimidines have two rings; purines have one
In 1928, Frederic Griffith showed that
A. The relative content of the four bases in DNA differed between organisms, but
the amount of G is always equal to C and the amount of A is always equal toT
B. The bacteriophage T2 introduces DNA, not protein, into the bacterium it
infects
C. DNA replication is semiconservative
D. Different alleles of the same gene can be either dominant or recessive in their
influence on phenotype
E. A chemical derived from dead bacteria can produce heritable changes in the
traits of living cells - ANSWER A chemical derived from dead bacteria can
produce heritable changes in the traits of living cells
In 1953, James Watson and Francis Crick accurately predicted the structure of
DNA. They based their prediction on experimental data obtained by which
technique?
A. Stoichiometry of elements
B. DNA sequence analysis
C. Gel electrophoresis
D. Electron microscopy
E. X-ray diffraction - ANSWER X-ray diffraction
