Molecular Genetics Test
1. The genetic specifications for assembling a protein are in the DNA. The first
step in protein
synthesis is for that code to be: (1.) transcribed to tRNA (2.) transcribed to
mRNA
(3.) translated to tRNA (4.) translated to mRNA
2. Which molecule hauls amino acids to the ribosomes? (1.) rRNA (2.) tRNA
(3.) DNA (4.) mRNA
3. Which is found in RNA but not in DNA? (1.) adenine (2.) cytosine (3.)
guanine (4.) uracil (5.) phosphate groups
4. Which of the following is TRUE of tRNA?
(1.) It functions in carrying the code from messenger RNA from the nucleus to
the ribosomes.
(2.) It consists of a single strand of nucleotides.
(3.) It is necessary for translation. (4.) all of the previous are true statements
5. Which statement about DNA is false?
(1.) The sugar in DNA has one less oxygen molecule than that in RNA.
(2.) DNA is a double stranded molecule.
(3.) In DNA, the base uracil replaces thymine.
(4.) DNA is a polymer made of nucleotide subunits.
6. The process of synthesizing mRNA along a DNA template is called
(1.) transcription (2.) translation (3.) transformation (4.) translocation (5.)
crossing over
In questions 7 and 8 below, a segment of DNA has one strand with the
following sequence of bases.
AGCGCATAGCAA
7. The complementary strand of DNA is
(1.) U C G C G U A U C G U U
(2.) T C G C C G A T C G T T
(3.) T C G C G T A T C G T T
(4.) T C G C A T T A C A U U
(5.) T C G W R O N G A C U U
8. The mRNA molecule coded for by the original strand is
(1.) T C G C G T A T C G T T
(2.) U C G C G U A U C G U U
(3.) T C A C M R N A T C C C
(4.) U A C A T T U C A G G G
(5.) U C G G C A T T U G G C
9. Which is true of a codon?
(1.) It consists of 64 nucleotides.
(2.) It may code for the same amino acid as another codon does.
(3.) It never codes for more than one amino acid.
(4.) It extends from one end of a tRNA molecule
(5.) It is the basic unit of the genetic code.
10. Which structure is coded for by the shortest (or smallest) sequence of
DNA?
(1.) a tRNA having 75 nucleotides
(2.) a mRNA having 75 codons
(3.) a polypeptide composed of 75 amino acids
(4.) a protein composed of 2 polypeptides, each 35 amino acids long
11. The nucleotides in DNA are grouped in triplets, or 3-letter words.
The number of 3-letter words that can be made from the DNA nucleotides
is
(1.) 64 (2.) 16 (3.) 20 (4.) 46
12. In what direction can a DNA polymerase work when catalyzing the
addition of nucleotide
monomers to build a strand of DNA?
(1.) from the 5' toward the 3' end of the new strand being assembled
(2.) from the replication centers in two directions called replication forks
(3.) from the 3' to the 5' end of the strand being assembled
(4.) in both directions if DNA ligase is present
13. The DNA of all organisms replicates by (1.) dispersive replication (2.)
reverse replication
(3.) semi-conservative replication (4.) conservative replication
14. The scientist(s) most associated with the currently accepted theory of DNA
replication is (are) (1.) Darwin and Lamarck (2.) Griffith and Wilkins (3.)
Meselson and Stahl (4.) Cartwright and Davis
15. The two sides of the DNA molecule are held together at their bases by:
(1.) covalent bonds (2.) peptide bonds (3.) James Bonds (4.) ionic charges (5.)
hydrogen bonds
16. The three parts of a nucleotide are held together by (1.) ionic bonds (2.)
covalent bonds
(3.) van der Waals forces (4.) hydrogen bonds (5.) James Bonds
17. The technology that finally clarified the structure of DNA was (1.)
autoradiography
(2.) ultracentrifugation (3.) electron microscopy (4.) X-ray diffraction (5.) gel
electrophoresis
18. Fred Griffith was able to determine that (1.) DNA was the genetic material
(2.) replication was semi-conservative (3.) genetic capabilities could be
transferred between bacteria
(4.) viruses consist of RNA and proteins (5.) DNA would undergo mutation
19. What kind of bond joins the complementary nucleotides? (1.) ionic bonds
(2.) nitrogenous bases
(3.) strands of RNA (4.) covalent bonds (5.) hydrogen bonds
20. By estimating the relative quantity of adenine, guanine, cytosine, and
thymine in the DNA
of various cells, Chargaff played an important role in clarifying the:
(1.) genetic code (2.) structure of DNA (3.) mechanism of translation (4.)
chemistry of RNA
(5.) principle of base-pairing
21. The actual assembly of amino acids into protein occurs on the
(1.) endoplasmic reticulum (2.) ribosomes (3.) tRNAs (4.) golgi bodies (5.)
none of these
22. To read the genetic code, the bases of DNA or RNA are placed in groups
of
(1.) 1 (2.) 4 (3.) 6 (4.) 8 (5.) none of these
23. The total number of codons possible in the code system is: (1.) 4 (2.) 16 (3.)
32 (4.) 64 (5.) none of these
24. Which remains in the nucleus during translation? (1.) tRNA (2.) mRNA (3.)
rRNA (4.) all of these
(5.) none of these
25. Which does NOT represent a difference between RNA and DNA?
(1.) RNA is single stranded.
(2.) RNA contains the sugar ribose.
(3.) RNA utilizes nucleotides in its structure.
(4.) RNA substitutes uracil for thymine.
(5.) All of the above represent differences between DNA and RNA.
26. Which represents a similarity between DNA and RNA?
(1.) Double-stranded helical structure
(2.) The presence of uracil
(3.) The same number of oxygen atoms in each of their pentose sugars
(4.) Nucleotides consisting of a phosphate, sugar, and nitrogenous base
(5.) The relative length of each molecule is similar
27. Research by biologists such as Beadle and Tatum has led to the now
questioned hypothesis that the
synthesis of each protein (enzyme) in a cell is governed by the action of a
single
(1.) gene (2.) chromosome (3.) nitrogenous base (4.) phosphate molecule
28. The coded information in a DNA molecule directly determines the
formation of
(1.) polypeptides (2.) polysaccharides (3.) lipids (4.) glycerol (5.)
monosaccharides
29. The S form of pneumococcus causes the disease pneumonia in mice, while
the R form
does not. The series of experiments on the R and S forms of pneumococcus
led to the
1944 discovery by Avery, McLeod, and McCarty that
(1.) both R and S forms could cause pneumonia
(2.) S cells had DNA, but R cells did not
(3.) R cells could be transformed by phage
(4.) the transforming factor for R cells is DNA
30. Electrophoresis is used to (1.) amplify small DNA samples to obtain
enough
for analysis (2.) clone genes (3.) match a gene with its function (4.) cut
DNA
into fragments (5.) separate fragments of DNA
31. DNA fingerprints used as evidence in a murder trial look something like
supermarket bar codes. The pattern of bars in a DNA fingerprint shows
(1.) the order of genes along particular chromosomes (2.) the presence
of various-sized fragments of DNA (3.) the exact location of a specific gene
in
a genomic library (4.) the presence of dominant or recessive alleles for
particular traits (5.) the order of bases in a particular gene
32. The immediate goal of the Human Genome Project is to (1.) Develop new
technologies
for studying DNA (2.) compare the genomes of a large number of
individuals
from different parts of the world (3.) map and sequence the genomes of
important research organisms such as Drosophila melanogaster (4.) map all
the human genes and determine the nucleotide sequence of the entire
human
genome (5.) find cures for human genetic disorders
33. The deoxyribo part in the name deoxyribonucleic acid refers to the (1.)
rungs of the sugar ladder
(2.) bonds that hold the two strands together (3.) sugar component of DNA
(4.) type of helical arrangement
34. Which of the statements about electrophoresis is FALSE? (1.) The process
requires an electric current. (2.) This technique can be used to separate
charged molecules. (3.) Large molecules migrate more slowly in the
agarose gel than small molecules. (4.) The technique can be used to easily
separate nonpolar molecules.
35. A nucleotide of DNA could contain (1.) adenine, ribose, and phosphate (2.)
nitrogenous base, phosphate, and glucose
(3.) phosphate, deoxyribose, and thymine (4.) uracil, deoxyribose and
phosphate
36. In recombinant DNA experiments,______ is used to cut pieces of DNA and
______ joins the resulting fragments to form recombinant DNA.
(1.) a transposon . . . a restriction enzyme (2.) a transposon . . . a plasmid
(3.) DNA ligase . . . a restriction enzyme (4.) a plasmid . . . DNA ligase
(5.) a restriction enzyme . . . DNA ligase
37. The phosphate and sugar groups of a nucleotide are held together by
(1.) ionic bonds (2.) covalent bonds (3.) van der Waals forces
(4.) hydrogen bonds (5.) James Bonds
38. The technology Rosalind Franklin was involved in that finally clarified the
structure of DNA was (1.) autoradiography (2.) ultracentrifugation
(3.) electron microscopy (4.) X-ray diffraction (5.) gel electrophoresis
39. Beadle and Tatum showed that each kind of mutant bread mold they studied
lacked a specific enzyme. Their experiments demonstrated that (1.) cells
need specific enzymes in order to function (2.) genes are made of DNA
(3.) enzymes are required to repair damaged DNA information (4.)
mutations
are changes in genetic information (5.) genes carry information for
making proteins
40. At one point as a cell carried out its day-to-day activities, the nucleotides
GAT
were paired with the nucleotides CUA. This pairing occurred (1.) when an
mRNA codon paired with a tRNA anticodon (2.) during translation
(3.) during transcription (4.) It is impossible to say, given this information
(5.) in a double-stranded DNA molecule
41. The information carried by a DNA molecule is in (1.) the sugars and
phosphates forming its backbone (2.) the total number of nucleotides it
contains (3.) the order of the nucleotides in the molecule (4.) its amino
acid sequence (5.) the RNA units that make up the molecule
42. Which are arranged in the correct order by size, from largest to smallest?
(1.) chromosome - gene - nucleotide - codon (2.) chromosome - gene codon - nucleotide
(3.) codon - chromosome - gene - nucleotide (4.) nucleotide - chromosome
- gene - codon
(5.) gene - chromosome - codon - nucleotide
43. During translation, chain elongation continues until (1.) no amino acids are
left
(2.) all tRNAs are empty (3.) the polypeptide is long enough
(4.) the ribosomes run off the end of mRNA (5.) chain terminator codons
occur
44. Imagine an error occurring during DNA replication in a cell, so that where
there
is supposed to be a T in one of the genes there is instead a G. What effect
will
this probably have on the cell? (1.) The amino acid sequence of one of its
kinds
of protein will be completely changed (2.) Each of its kinds of protein will
contain an incorrect amino acid (3.) One of its kinds of protein might
contain
an incorrect amino acid (4.) An amino acid will be missing from one of its
kinds
of protein (5.) An amino acid will be missing from each of its kinds of
protein
45. A geneticist found that a particular mutation had no effect on the
polypeptide encoded by a gene. This mutation probably involved
(1.) deletion of the entire gene (2.) insertion of one nucleotide
(3.) substitution of one nucleotide (4.) deletion of one nucleotide
(5.) alteration of the start codon
46. During the process of translation (polypeptide synthesis), ____ matches
an mRNA codon with the proper amino acid. (1.) DNA polymerase
(2.) transfer RNA (3.) a ribosome (4.) messenger RNA (5.) GTP
47. Each nucleotide in a DNA molecule is composed of (1.) a nitrogenous base
and a
phosphate group (2.) a sugar called ribose, a nitrogenous base, and a
phosphate group
(3.) a sugar called deoxyribose, a nitrogenous base, and a phosphate group
(4.) a sugar
called deoxyribose and a phosphate group (5.) deoxyribose and a nitrogen
base.
48. The bases on one strand of DNA are CTAGAAC. The complementary
section on the other strand of
DNA is (1.) CTAGAAC (2.) AGCTCCA (3.) GATCTTG (4.)
TCGAGGT (5.) GUTCTTG.
49. Covalent bonds between the nucleotides of new DNA strands are formed by
enzymes called
(1.) pyrimidines (2.) purines (3.) nucleotides (4.) transforming factors
(5.) DNA polymerases.
50. DNA replication occurs, ensuring that cells in a multicellular organism
carry the same genetic information.
(1.) in a few hours (2.) slowly (3.) before a cell divides (4.) after
completed cell division
51. Each gene minimally dictates the production of one (1.) chromosome (2.)
codon
(3.) tRNA (4.) DNA strand (5.) polypeptide.
52. Transcription is the process of converting a nucleotide sequence of DNA
into
(1.) a single strand of RNA (2.) a double strand of RNA (3.) a single
complementary helix of DNA.
(4.) protein (5.) polypeptides.
53. The conversion of a sequence of RNA nucleotides into a sequence of amino
acids is called
(1.) transcription (2.) replication (3.) RNA splicing (4.) translation (5.)
mutation.
54. mRNA directs the building of proteins through a sequence of (1.) introns
(2.) codons.
(3.) exons (4.) anticodons (5.) proteins
55. The RNA molecule used during transcription is (1.) transfer RNA (2.)
ribosomal RNA
(3.) transcription RNA (4.) messenger RNA (5.) polymerase RNA.
56. The codons of mRNA are translated to amino acids by
(1.) translation RNA (2.) transcription RNA (3.) transfer RNA. (4.)
messenger RNA.
(5.) ribosomal RNA.
57. Any change in a nucleotide sequence of DNA is called (1.) mutagen (2.)
replication
(3.) duplication (4.) splicing (5.) mutation
58. Rejoining DNA fragments from two organisms is best known as (1.)
conjugating DNA
(2.) mapping genes (3.) recombinant DNA technology (4.) gene
sequencing
59. The gene-cutting tools of recombinant DNA technology are (1.) helicases
(2.) DNA ligases
(3.) DNA vectors (4.) plasmids (5.) restriction enzymes
Questions 60 and 61 refer to information in the table of codons.
Use the table of codons
60. A single substitution in the third position would have the greatest
probability of mutational effect on the
codon (1.) GUU (2.) AUU (3.) CGU (4.) AUG (5.) CCC
61. Which amino has the greatest number of codons? (1.) Leucine (leu) (2.)
Proline (pro)
(3.) Tryptophan (trp) (4.) Glutamic acid (glu) (5.) Asparic acid (asp)
62. The "one gene one protein " theory can be explained how genes control in
cells by
(1.) determining polypeptide chains (2.) interacting with proteins in the
chromosomes
(3.) assorting independently during meiosis (4.) inhibiting enzyme
formation in some cell reactions
(5.) replicating before the beginning mitosis
63. Point mutations (1.) remain in the parent and cannot be passed on to the
offspring
(2.) occur at the 5' end of a DNA strand (3.) forces the genetic code to be
read from the wrong point
(4.) are caused by a break in the chromosome (5.) result when one
nucleotide is changed for another
Use the diagram of a technique in molecular biology and your knowledge of
biology to answer questions
64 to 66 that follow.
64. The technique being used to assess this information is called
(1.) human genome determination (2.) karyotyping
(3.) transformation (4.) DNA blotting (5.) electrophoresis
65. Based on the indicated position of the wells, the longest DNA fragment in
the crime
scene sample is at position (1.) 1 (2.) 2 (3.) 3 (4.) 4 (5.) 5
66. Based on the results of this forensic investigation, it is likely that
the guilty culprit is (1.) Mr. Bean (2.) Bob (3.) Ray (4.) Tim (5.) Mr.
Rogers
Use the diagram below to assist you in answering questions 67 through 69.
67. Structure A contains a (1.) genetic code (2.) messenger RNA molecule
(3.) single nucleotide, only (4.) small polysaccharide (5.) male gamete
68. Structure B represents (1.) a ribosome (2.) recombinant DNA
(3.) transfer RNA (4.) a female gamete
69. The technique illustrated in the diagram is known as (1.) cloning
(2.) protein synthesis (3.) genetic engineering (4.) in vitro fertilization
Correctly complete the statements below .
1. The fact that adenine bonds with thymine and guanine with cytosine provides an
example of the concept of _______________ base pairing.
2. DNA is a polymer made up of _______________ subunits.
3. The enzyme which cuts a DNA molecule into smaller pieces is called a(n)
___________.
4. The transfer of segments of DNA from one species into another is referred to as
______________ technology.
5. A triplet of mRNA is called a(n) _______________.
6. A triplet of tRNA is called a(n) _______________.
7. The currently most accepted theory of DNA replication is that of ________________
replication.
8. A pattern of a single strand of DNA or RNA used in the replication process is called
a(n) _______________.
9. The currently most accepted theory of DNA replication was supported
by experimental work completed by _______________ and Stahl.
10. In RNA, the base uracil replaces the base _______________.
11. RNA is a _______________ stranded molecule.
12. The sugar found in the DNA molecule is called _______________.
13. The enzyme _______________ separates the DNA strands thus allowing the
replication
process to occur.
14. The process of forming mRNA from DNA is called _______________.
15. The fact that adenine/thymine and guanine/cytosine are found in relatively equal
percentages in a cell is a statement of a concept first proposed by _______________.
16. The sequence of DNA which stops the transcription process is called
_______________.
17. The _______________ is the region of a DNA strand where the replication process is
occurring.
18. The translation of _______________ occurs on the ribosomes of a cell.
19. The total number of possible codons is _____.
20. The fact that frequently several different triplets can code for the same amino acid
is proof that the genetic code is _______________.
21. A(n) ______________ is a part of the mRNA as transcribed from the DNA that
contains a portion of
the information necessary for final gene product.
22. A(n) ______________ is an intervening or noncoding segment of a gene.
[Short Answer]
1. Discuss the process of protein synthesis and their possible problems caused a frame
shift mutation.
2. A portion of a specific DNA molecule consists of the following sequence of
nucleotide triplets:
TAC GAA CTT CGG TCC
This DNA sequence codes for the following short polypeptide:
methionine - leucine - glutamic acid - proline - arginine
a.) Describe the steps in the synthesis of this polypeptide.
b.) What would be the effect of a deleltion or an addition in one of the DNA nucleotides?
Explain why this would result in a frameshift mutation.
c.) What would be the effect of a substitution in one of the nucleotides? Explain why this is
called a point
mutation. Give an example in this DNA sequence (or the m RNA made from it) how a point
mutation
may not result in a different protein being synthesized by this organism.
3. The diagram below shows a segment of DNA with a total length of 4,900 base
pairs. The arrows indicate reaction sites
for two restriction enzymes (enzyme X and enzyme Y).
(A) Explain how the principles of gel electrophoresis allow for the separation of DNA
fragments.
(B) Describe the results you would expect from electrophoretic separation of fragments
from the following treatments of the DNA segment above. Assume that the
digestion occurred under appropriate conditions and went to completion.
I. DNA digested with only enzyme X
II. DNA digested with only enzyme Y
III. Undigested DNA
(C) Explain both of the following:
(1). The mechanism of action of restriction enzymes
(2). The different results you would expect if a mutation occurred at the
recognition site for enzyme Y.
4. Use the graphic at the left to assist you
in answering the following questions.
a.) Describe how the technique shown at
the left can be used to make human insulin
in bacterial cells such as E. Coli. Identify
the name of this technique.
b.) Describe the process indicated at the left
and explain how enzymes such as restriction
enzymes and DNA ligase are involved in
this process.
c.) List at least three other specific uses for
this technique in molecular biology.
5. Discuss and describe Griffith's bacterial transformation experiment.
Now hopefully the correct answers!
Multiple Choice Section
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9.
2
2
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2
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1
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27.
Completion Section
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
complementary
nucleotide
restriction enzyme
recombinant DNA
codon
anticodon
semi-conservative
template
Meselson
thymine
5
5
2
5
4
5
3
4
1
28.
29.
30.
31.
32.
33.
34.
35.
36.
1
4
5
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3
4
3
5
37.
38.
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40.
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42.
43.
44.
45.
2
4
5
3
3
2
5
3
3
46.
47.
48.
49.
50.
51.
52.
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54.
2
3
3
5
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1
1
2
55.
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63.
4
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2
1
1
5
64.
65.
66.
67.
68.
69.
5
2
4
1
2
3
11.
12.
13.
14.
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16.
17.
18.
19.
20.
21.
22.
single
deoxyribose
DNA helicase (or helicase)
transcription
Chargaff
terminator or stop codon
replication origin
genetic code for polypeptides
64
degenerate
exon
intron
Short Answer
1. A brief discussion of protein synthesis:
a. DNA serves as a template for the synthesis of mRNA from RNA nucleotides
in the nucleus.
transcription: transfer of the genetic message from DNA to mRNA
RNA polymerase -- enzyme which catalyzes this transfer
b. mRNA molecules carrying a specific code determined by the base sequence
of the DNA template move from the nucleus to the cytoplasm.
c. Strands of mRNA carrying codons transcribed from DNA, move to the
ribosomes in the cytoplasm.
codon: a triplet in a RNA molecule triplet: grouping of three nitrogenous bases
in DNA or RNA molecules
d. mRNA strands become associated with rRNA on the ribosomes. (rRNA -arranges date between mRNA and tRNA)
e. Different triplets of nitrogenous bases in tRNA molecules pick up specific
amino acids in the cytoplasm and carry them to mRNA at the ribosomes.
(tRNA -- I want aa.)
anticodon -- nucleotide triplet in tRNA that base pairs with a complementary
nucleotide codon in mRNA
f. Amino acids are put into position on the ribosome with instructions from the
triplet codes of tRNA and mRNA.
g. With the aid of enzymes and ATP (energy), the amino acids are bonded to
form a polypeptide chain (protein) on the ribosome.
A frame shift mutation will result of a nitrogenous base is added or deleted to
the sequence of nitrogenous bases. This will result in the entire "reading
frame" which will result in a polypeptide being synthesized with an almost
completely different amino acid sequence. The effects of this kind of mutation
are much more significant than those of a point mutation, which changes just
one nitrogenous base in a position, and may or may not change an amino acid.