Exam 4

Question 1

Garrod hypothesized that “inborn errors of metabolism” such as alkaptonuria occur because
A) certain metabolic reactions are carried out by ribozymes, and affected individuals lack key splicing factors
B) enzymes are made of DNA, and affected individuals lack DNA polymerase
C) genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack
certain enzymes
D) metabolic enzymes require vitamin cofactors, and affected individuals have significant nutritional deficiencies
E) none of the above

Answer 1

C) genes dictate the production of specific enzymes, and affected individuals have genetic defects that cause them to lack
certain enzymes

Question 2

The genetic code is essentially the same for all organisms. From this, one can logically assume which of the following?
A) the same codons in different organisms translate into different amino acids
B) different organisms have different types of amino acids
C) a gene from an organism can theoretically be expressed by any other organism
D) DNA was the first genetic material
E) none of the above

Answer 2

C) a gene from an organism can theoretically be expressed by any other organism

Question 3

What would the anticodon be for a tRNA that transports
phenylalanine to a ribosome?
A) TTT
B) UUU
C) CCC
D) AAA
E) none of the above

Answer 3

D) AAA

Question 4

What does it mean when we say the genetic code is redundant?
A) more than one codon can specify the addition of the same amino acid
B) a single codon can specify the addition of more than one amino acid
C) the genetic code is different for different domains of organisms
D) the genetic code is universal (the same for all organisms)
E) none of the above

Answer 4

A) more than one codon can specify the addition of the same amino acid

Question 5

A particular triplet of bases in the template strand of DNA is 5’ CTA 3’. The corresponding codon for the mRNA transcribed is
A) 5’ TCA 3’
B) 3’ UGA 5’
C) 3’ GAU 5’
D) 3’ ACU 5’
E) either UCA or TCA, depending on wobble in the first base

Answer 5

C) 3’ GAU 5’

Question 6

At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork:

3’ C C T A G G C T C G A A T G G 5’

An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence?
A) 5’ G C C T A G G 3’
B) 5’ A G C U U A C C 3’
C) 5’ G C C U A G G 3’
D) 3’ G C C T A G G 5’
E) 5’ A C G T T A G G 3’

Answer 6

B) 5’ A G C U U A C C 3’

Question 7

According to the central dogma, what molecule should go in the blank? DNA ĺ _____ ĺ Proteins
A) mRNA
B) rRNA
C) mtDNA
D) tRNA
E) none of the above

Answer 7

A) mRNA

Question 8

A mutant bacterial cell has a defective aminoacyl-tRNA synthetase that attaches a lysine to tRNAs with the anticodon AAA instead
of the normal phenylalanine. The consequence of this for the cell will be that
A) the ribosome will skip a codon every time a UUU is encountered
B) the cell will compensate for the defect by attaching phenylalanine to tRNAs with lysine-specifying anticodons
C) none of the proteins in the cell will contain phenylalanine
D) proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU
E) none of the options will occur; the cell will recognize the error and destroy the tRNA

Answer 8

D) proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU

Question 9

In the structural organization of many eukaryotic genes, individual exons may be related to which of the following?
A) the various domains of the polypeptide product
B) the sequence of the intron that immediately precedes each exon
C) the number of start sites for transcription
D) the number of polypeptides making up the functional protein
E) none of the above

Answer 9

A) the various domains of the polypeptide product

Question 10

Which of the following is a protein produced by a regulatory gene?
A) inducer
B) repressor
C) promoter
D) operon
E) none of the above

Answer 10

B) repressor

Question 11

What type of bonding is responsible for maintaining the shape of the tRNA molecule shown to
the right?
A) van der Waals interactions between hydrogen atoms
B) peptide bonding between amino acids
C) ionic bonding between phosphates
D) hydrogen bonding between base pairs
E) none of the above

Answer 11

D) hydrogen bonding between base pairs

Question 12

The tryptophan operon is a repressible operon that is
A) permanently turned on
B) turned on only when glucose is present in the growth medium
C) turned off whenever tryptophan is added to the growth medium
D) turned off only when glucose is present in the growth medium
E) turned on only when tryptophan is present in the growth medium

Answer 12

C) turned off whenever tryptophan is added to the growth medium

Question 13

23) A mutation that inactivates a regulatory gene of a repressible operon in an E. coli cell would result in
A) complete inhibition of transcription of the structural gene controlled by that regulator
B) irreversible binding of the repressor to the operator
C) continuous translation of the mRNA because of alteration of its structure
D) continuous transcription of the structural gene controlled by that regulator
E) none of the above

Answer 13

D) continuous transcription of the structural gene controlled by that regulator

Question 14

In eukaryotes, general transcription factors
A) bind to mRNA and degrade them
B) bind to sequences just after the start site of transcription
C) bind to mRNA and stimulate translation
D) inhibit RNA polymerase binding to the promoter and begin transcribing
E) none of the above

Answer 14

E) none of the above

Question 15

CAP is said to be responsible for positive regulation of the lac operon because
A) CAP binds to the CAP-binding site
B) CAP binds cAMP
C) CAP bound to the CAP-binding site increases the frequency of transcription initiation
D) CAP prevents binding of the repressor to the operator
E) none of the above

Answer 15

C) CAP bound to the CAP-binding site increases the frequency of transcription initiation

Question 16

The product of the bicoid gene in Drosophila provides essential information about
A) segmentation
B) lethal genes
C) muscle cell differentiation
D) wing development
E) none of the above

Answer 16

E) none of the above

Question 17

The phenomenon in which RNA molecules in a cell are destroyed if they have a sequence complementary to an introduced double-
stranded RNA is called

A) RNA blocking
B) RNA disposal
C) RNA obstruction
D) RNA interference
E) none of the above

Answer 17

D) RNA interference

Question 18

Which of the following types of mutation would convert a proto-oncogene into an oncogene?
A) a mutation that creates an unstable proto-oncogene mRNA
B) a deletion of most of the proto-oncogene coding sequence
C) a mutation that greatly increases the amount of the proto-oncogene protein
D) a mutation that blocks transcription of the proto-oncogene
E) none of the above

Answer 18

C) a mutation that greatly increases the amount of the proto-oncogene protein

Question 19

Tumor-suppressor genes _____.
A) often encode proteins that stimulate the cell cycle
B) are frequently overexpressed in cancerous cells
C) are cancer-causing genes introduced into cells by viruses
D) encode proteins that help prevent uncontrolled cell growth
E) none of the above

Answer 19

D) encode proteins that help prevent uncontrolled cell growth

Question 20

Which of the following is an example of post-transcriptional control of gene expression?
A) the removal of introns and alternative splicing of exons
B) the binding of transcription factors to a promoter
C) the addition of methyl groups to cytosine bases of DNA
D) the folding of DNA to form heterochromatin
E) gene amplification contributing to cancer

Answer 20

A) the removal of introns and alternative splicing of exons

Question 21

Genomic imprinting, DNA methylation, and histone acetylation are all examples of
A) karyotypes
B) translocation
C) chromosomal rearrangements
D) epigenetic phenomena
E) genetic mutation

Answer 21

D) epigenetic phenomena

Question 22

Which of the following statements about the DNA in one of your brain cells is true?
A) most of the DNA codes for protein
B) the majority of genes are likely to be transcribed
C) each gene lies immediately adjacent to an enhancer
D) it is the same as the DNA in one of your heart cells
E) many genes are grouped into operon-like clusters

Answer 22

D) it is the same as the DNA in one of your heart cells

Question 23

The following enzyme is necessary to generate a complementary DNA library:
A) complementarase
B) reverse complementarase
C) librase
D) restriction enzyme
E) none of the above

Answer 23

E) none of the above

Question 24

Agent Scully was able to complete the following technique (in under two hours) combining gel electrophoresis of DNA fragments
with nucleic acid hybridization in order to demonstrate the existence of alien DNA which had integrated into her own DNA
A) Eastern blot
B) Southern blot
C) polymerase chain reaction
D) restriction fragment length polymorphism
E) none of the above

Answer 24

B) Southern blot

Question 25

Scientists can utilize the following techniques in order to get DNA inside a target cell:
A) electroporation
B) electrocution
C) electromagnetic waves
D) static electricity
E) having an electrifying personality

Answer 25

A) electroporation

Question 26

A principal problem with inserting an unmodified mammalian gene into a plasmid and then getting that gene expressed in bacteria
is that
A) bacteria translate only mRNAs that have multiple messages
B) prokaryotes use a different genetic code from that of eukaryotes
C) bacterial RNA polymerase cannot make RNA complementary to mammalian DNA
D) bacteria cannot remove eukaryotic introns
E) none of the above

Answer 26

D) bacteria cannot remove eukaryotic introns

Question 27

The reason for using Taq polymerase for PCR is that _____.
A) it is heat stable and can withstand the heating step of PCR
B) only minute amounts are needed for each cycle of PCR
C) it has regions that are complementary to the primers
D) it binds more readily than other polymerases to the primers
E) none of the above

Answer 27

A) it is heat stable and can withstand the heating step of PCR

Question 28

In order to insert a human gene into a plasmid, both must
A) have identical DNA sequences
B) originate from the same type of cell
C) code for the same gene product
D) be cut by the same restriction enzyme
E) be the same length

Answer 28

D) be cut by the same restriction enzyme

Question 29

Which of the following is true of embryonic stem cells but not of adult stem cells?
A) One aim of using them is to provide cells for repair of diseased tissue
B) They can provide enormous amounts of information about the process of gene regulation
C) They normally differentiate into only eggs and sperm
D) They can continue to reproduce for an indefinite period
E) They can give rise to all cell types in the organism

Answer 29

E) They can give rise to all cell types in the organism

Question 30

Cold case detectives are investigating a homicide that took place 30 years ago. In reexamining the evidence, they find a tiny spot of
blood on the victim’s clothing that was likely left by the murderer. The DNA in the blood has partially degraded over time. What
technique would the blood lab technicians use in their examination of this tiny, degraded blood sample?
A) restriction enzyme digest and DNA ligase to make recombinant DNA from this sample
B) Southern blot analysis
C) electroporation
D) DNA microarray analysis
E) none of the above

Answer 30

E) none of the above

Question 31

41) DNA microarrays have made a huge impact on genomic studies because they
A) can be used to eliminate the function of any gene in the genome
B) allow the expression of many or even all of the genes in the genome to be compared at once
C) allow physical maps of the genome to be assembled in a very short time
D) dramatically enhance the efficiency of restriction enzymes
E) can be used to introduce entire genomes into bacterial cells

Answer 31

B) allow the expression of many or even all of the genes in the genome to be compared at once

Question 32

Relatively short DNA fragments can be sequenced using
A) reverse transcriptase
B) dideoxyribonucleotides tagged with a distinct fluorescent label
C) a fluorescently labeled probe
D) siRNA
E) none of the above

Answer 32

B) dideoxyribonucleotides tagged with a distinct fluorescent labe

Question 33

What methodology is normally utilized to insert a cloned gene into bone marrow cells from patients to correct a defective gene?
A) infection with a retrovirus carrying the RNA version of the normal gene
B) a BAC
C) in vitro mutagenesis
D) in situ hybridization
E) none of the above

Answer 33

A) infection with a retrovirus carrying the RNA version of the normal gene

Question 34

Gene function can be determined by disabling the gene using
A) in vitro mutagenesis
B) reverse transcriptase- polymerase chain reaction
C) in situ hybridization
D) nuclear transplantation
E) none of the above

Answer 34

A) in vitro mutagenesis

Question 35

Why is it so important to be able to amplify DNA fragments when studying genes?
A) restriction enzymes (endonucleases) cut DNA into fragments that are too small
B) a gene may represent only a millionth of the cell’s DNA
C) before amplification, DNA fragments are likely to bind to RNA and no longer be
able to be analyzed
D) a clone requires multiple copies of each gene per clone
E) none of the above

Answer 35

B) a gene may represent only a millionth of the cell’s DNA

Question 36

A laboratory might use dideoxyribonucleotides to
A) visualize DNA expression
B) separate DNA fragments
C) sequence a DNA fragment
D) produce cDNA from mRNA
E) none of the above

Answer 36

C) sequence a DNA fragment

Question 37

The first cloned cat, called Carbon Copy, was a calico, but she looked significantly different from her female parent because
A) the cloning was done poorly and it was likely that some contaminating cat DNA became part of Carbon Copys genome
B) X inactivation in the embryo is random and produces different patterns
C) cloned animals have been found to have a higher frequency of transposon activation
D) fur color genes in cats is determined by differential acetylation patterns
E) none of the above

Answer 37

B) X inactivation in the embryo is random and produces different patterns

Question 38

For applications in gene therapy, what is the most favorable characteristic of retroviruses?
A) retroviruses have an RNA genome
B) retroviruses possess reverse transcriptase
C) DNA copies of retroviral genomes become integrated into the genome of the infected cell
D) retroviruses mutate often
E) none of the above

Answer 38

C) DNA copies of retroviral genomes become integrated into the genome of the infected cell

Question 39

Dr. Feuer would like to clone himself so that he can go surfing while his clone teaches BIOL 203. In the end, Dr. Feuer decides
against this foolish plan for the following reasons:
A) ethical and moral considerations
B) telomere shortening may contribute to disease if the donor nucleus is removed from somatic cells for cloning purposes
C) only a small percentage of cloned embryos have developed normally to birth most likely since epigenetic changes must be
reversed in the donor nucleus
D) Dr. Feuer is concerned that his clone may be a better surfer than himself
E) all of the above

Answer 39

E) all of the above