324 MHR • Unit 3 Molecular Genetics
REVIEW
UNIT 3
Multiple Choice
In your notebook, write the letter of the best
answer for each of the following questions.
1.Friedrich Miescher is known for being the first
scientist to
(a)isolate nuclein from white blood cells
(b)show the link between nuclein and
Mendel’s “factors of inheritance”
(c)argue that protein, not DNA, is the material
of heredity
(d)distinguish between DNA and RNA
(e)propose that DNA is the material of heredity
2.The experiments of Avery, MacLeod, and
McCarthy were significant because they
demonstrated that
(a)bacteria can remain pathogenic even after
they have been killed
(b)transformation takes place when the
pathogenic bacteria are treated with a
protein-destroying enzyme, but not when
they are treated with an RNA-destroying
enzyme
(c)transformation takes place when pathogenic
bacteria treated with a DNA-destroying
enzyme are cultured with non-pathogenic
bacteria
(d)transformation takes place only when the
DNA of the pathogenic cells is intact
(e)treating pathogenic bacteria with a DNA-
destroying enzyme has the same effect as
heat-killing the cells
3.Which of the following did not contribute to
Watson and Crick’s work to determine the
structure of the DNA molecule?
(a)Chargaff’s findings about the nucleotide
composition of DNA
(b)Franklin’s study of X-ray diffraction images
of DNA
(c)Levene’s findings about the arrangement of
nucleotides in nucleic acids
(d)knowledge of the molecular properties of
nitrogenous bases
(e)Franklin’s observations about the way DNA
reacts to water
4.In a strand of DNA, each nitrogenous base is
(a)bound to a phosphate group and to a
deoxyribose molecule
(b)connected to the next nitrogenous base
through a phosphate bridge(c)connected to a deoxyribose molecule
through a phosphate bridge
(d)capable of forming a hydrogen bond with
another nitrogenous base
(e)(a) and (d)
5.Which of the following statements is not correct?
(a)Proteins play an important role in packing
DNA in eukaryotes, but not in prokaryotes.
(b)Prokaryotic cells may contain more than
one molecule of DNA.
(c)All living cells use DNA as their genetic
material.
(d)DNA may be packed to different degrees
within the same eukaryotic cell.
(e)The packing of DNA plays a role in
regulating gene expression.
6.Which of the following statements about the
eukaryotic genome is true?
(a)The best functional definition of a gene is
that one gene codes for one polypeptide.
(b)Most of the DNA is usually found in a
supercoiled form, although it will condense
further during replication.
(c)The size of the genome is loosely related
to the organizational complexity of the
organism.
(d)The removal of exons determines the
polypeptide product of a gene.
(e)Over 90 percent of the genome may be
made up of non-coding sequences.
7.Which of the following is not evidence in
support of the triplet hypothesis?
(a)Four nucleotides can code for 20 nucleic
acids.
(b)The insertion of three nucleotides into a
strand of DNA causes a slight change to
the protein product.
(c)More than one codon can code for a
particular amino acid.
(d)The insertion of a single nucleotide into
a strand of DNA causes a major disruption
to the coding sequence.
(e)Three codons do not code for any amino
acid.
8.Which of the following statements about gene
expression is incorrect?
(a)A molecule of mRNA will have a nucleotide
sequence similar to that on the antisense
strand of the DNA molecule, except that it
will have U nucleotides in the place of the
antisense strand’s T nucleotides.UNDERSTANDING CONCEPTS