EXAM3-Fall07ANS

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BIOL. 303 EXAM III 11/30/07
----------------------------------------------------------------------------------------------------------------This exam consists of 40 multiple choice questions worth 2.5 points each. On
the separate answer sheet, please fill-in the single best choice for each question.
Please bubble-in your name on the answer sheet, leaving a space between first
and last names. Also, bubble-in the last 5 digits of your social security number
under “ID NUMBER” beginning in the left-most column. Good luck!
-----------------------------------------------------------------------------------------------------------------1.
What is the term which refers to a contiguous set of genes which are under
coordinate control?
A. lysogen.
B. prototroph.
C. operon.
D. allosteric.
2.
In the lac operon, under which of the following conditions will the lac genes be
transcribed at high levels?
A.
B.
C.
D.
3.
low glucose, low lactose
high glucose, low lactose
low glucose, high lactose
high glucose, high lactose
The lac operon
A. is under negative and positive control.
B. is under positive control only.
C. is normally expressed constitutively.
D. is an example of tissue-specific expression.
4.
RNA polymerase binds to the:
A.
B.
C.
D.
operator
repressor
inducer
promoter
5.
For the E. coli genotype I+P+OcZ+Y+A+, the expression of β-galactosidase will be:
A. inducible
B. constitutive
C. absent
D. none of the above
6.
With regards to the trp operon,
A. tryptophan is an inducer.
B. tryptophan is a co-repressor.
C. attenuation can halt replication.
D. none of the above.
7.
Under the system of genetic control of the trp operon,
A. when there are high levels of tryptophan in the medium, transcription of the
trp operon occurs at high levels.
B. when there are high levels of tryptophan in the medium, transcription of CAP
occurs at high levels.
C. when there are high levels of tryptophan in the medium, ribosomes “stall” and
reduce the levels of tryptophan synthesized.
D. when there is no tryptophan in the medium, transcription of the trp operon
occurs at high levels.
8.
Regarding the trp operon in B. subtilis, TRAP influences gene expression
A.
B.
C.
D.
at the posttranslational level
at the transcriptional level
both 1 and 2
none of the above
9.
Three posttranscriptional modifications often seen in the maturation of mRNA in
eukaryotes are
A.
B.
C.
D.
5'-capping, 3'-poly(A) tail addition, splicing
3'-capping, 5'-poly(A) tail addition, splicing
removal of exons, insertion of introns, capping
5'-poly(A) tail addition, insertion of introns, capping
10.
When studying the initiation of transcription, one often finds consensus
sequences located in the region of the DNA where RNA polymerase(s) bind. Which are
common consensus sequences?
A.
B.
C.
D.
11.
CAAT, TATA
GGTTC, TTAT
TTTTAAAA, GGGGCCCC
any trinucleotide repeat
Protein-encoding genes in eukaryotes are transcribed by
A. RNA polymerase I
B. RNA polymerase II
C. RNA polymerase III
D. RNA polymerase IV
12.
An intron is a section of
A.
B.
C.
D.
13.
protein that is clipped out posttranslationally.
RNA that is removed during RNA processing.
DNA that is removed during DNA processing.
transfer RNA that binds to the anticodon.
Transcription factors act as_________.
A. cis-acting regulatory elements
B. trans-acting regulatory elements
C. promoters
D. enhancers
14.
SWI-SNF proteins are involved in:
A.
B.
C.
D.
basal transcription
RNA interference
repression
chromatin remodeling
15.
Eukaryotic cells are able to carefully regulate precise levels of transcription in
specific genes encoding structural proteins through:
A. complex enhancer elements that can associate with multiple activator and
repressor proteins
B. production of different types of sigma factors
C. attenuation
D. all of the above
16.
What modification neutralizes the charges on histones and loosens up the
interactions between histones and DNA?
A. phosphorylation
B. methylation
C. acetylation
D. polyadenylation
17.
Which of the following can account for multiple proteins from a primary
transcript?
A. alternative splicing
B. reverse transcription
C. 5' methylation
D. polyribosomes
18.
In general, methylation of DNA in eukaryotes
A. induces genetic rearrangements
B. activates gene expression
C. promotes cell growth
D. reduces levels of gene expression
19.
The term "chromatin remodeling" refers to
A. a process that only bacteria perform since they contain no nucleus.
B. a process that is exclusively associated with transcription by RNA polymerase
III in eukaryotes.
C. alteration in chromatin structure to facilitate loading and translation by
ribosomes and, thus, enhance gene expression.
D. alteration of chromatin structure in association with transcription.
20.
The phenomenon known as “RNAi” (RNA interference) can be used
experimentally to
A. reduce expression of a specific target gene.
B. reduce transcription rate from a specific gene promoter.
C. interfere with replication.
D. enhance gene expression.
21.
Controls that tie the integrity of the genome with progression through the cell
cycle are known as:
A. growth factors
B. receptors
C. cyclins
D. checkpoints
22.
The spread of cancer cells to sites away from the initial tumor is known as:
A. angiogenesis
B. clonal replication
C. apoptosis
D. metastasis
23.
Genes that can contribute to cancer through increased expression are:
A. tumor suppressor genes
B. oncogenes
C. CDK inhibitors
D. nonexistent
24.
Genes that can contribute to cancer through a loss-of-function mutation are:
A.
B.
C.
D.
tumor suppressor genes
oncogenes
proto-oncogenes
cyclin-dependent kinases
25.
Sporadic cancers arise from __________; familial cancers arise from
_________.
A. somatic mutations; germline mutations
B. somatic mutations; germline mutations in combination with somatic mutations
C. germline mutations; somatic mutations
D. germline mutations; stem cell mutations
26.
What is the name of the protein that helps to regulate multiple checkpoints
throughout the cell cycle and is also known as the “guardian of the genome?”
A. p34
B. p102
C. cyclin
D. p53
27. A person born with an inherited predisposition to cancer usually does not develop
cancer until after
A.
B.
C.
D.
exposure to radiation.
loss of heterozygosity (LOH) of the inherited mutation.
age 70
Mardis Gras
28.
Regarding the relationship between viruses and cancer, which statement is most
accurate?
A. viruses cause some cancers in animals, but viruses are not associated with
cancer in humans.
B. most human cancers are known to be caused by viruses.
C. viruses are not associated with cancer in animals or humans
D. some cancers in humans can possibly be prevented by vaccination against a
virus.
29.
A restriction enzyme
A. cuts DNA at random
B. degrades RNA
C. normally cleaves DNA within a specific sequence
D. none of the above
30.
What is the function of an antibiotic-resistance gene in a vector?
A. To allow resistant transformants to grow in selective medium
B. To distinguish introns from exons
C. To screen for vectors with inserts
D. To allow plasmid replication
31.
What information is present in a cDNA library?
A.
B.
C.
D.
32.
intron sequences
promoter sequences
exon sequences
telomere sequences
Which of the following is needed in order to amplify a DNA fragment by PCR?
A. a set of primers.
B. knowledge of the complete nucleotide sequence of the fragment to be
amplified.
C. RNA polymerase.
D. dideoxynucleotide triphosphates.
33.
Nucleic acid blotting is widely used in recombinant DNA technology. In a
Northern blot one generally
A. hybridizes filter-bound DNA with a DNA probe.
B. hybridizes filter-bound RNA with a DNA probe.
C. examines amino acid substitutions with radioactive probes.
D. cleaves RNA with restriction endonucleases.
34.
Regarding the sequencing of genomes, which statement is true?
A. most of the human genome has been sequenced.
B. no eukaryotic genome has yet been sequenced.
C. DNA sequencing has revealed a complete lack of polycistronic transcription
units in eukaryotic genomes.
D. fewer than 300 genomes have been sequenced.
35.
Analysis of the human genome has revealed that about half (or maybe more) of
the human genome seems to be composed of
A
B.
C.
D.
protein-coding genes.
ribosomal RNA genes.
transposons or transposon-like elements.
satellite sequences.
36.
Based on the sequencing of Craig Venter’s diploid genome, researchers have
determined that
A. genomes of different individuals are even more similar than previously thought
B. genomes of different individuals display greater diversity than previously
thought.
C. the number of different human genes is greater than 50,000
D. the human and dog genomes are virtually identical.
37.
One reason that yeast are useful as model organisms is that
A.
B.
C.
D.
38.
P elements
A.
B.
C.
D.
39.
yeast are prokaryotes
yeast are very useful for developmental biology studies
there are absolutely no introns in the yeast genome
yeast can be grown as either haploid or diploid cells.
infect human cells
can be used to make transgenic mice
induce meiosis in yeast
are useful for introducing genes into Drosophila
If two mutations complement each other in a complementation test,
A. the two mutations reside in separate genes
B. the two mutations reside in the same gene
C. the mutations are epistatic to one another
D. one mutation must be a suppressor of the other.
40.
“Gene targeting” refers to
A.
B.
C.
D.
making an alteration or disruption in a specific gene in a genome
randomly integrating a gene into an organism’s genome
studying the transcription level of a particular gene.
shopping for a particular brand of pants.
That’s all!
Q: 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,16,17,18,19,20,21,
A: C, C, A, D, B, B, D, B, A, A, B, B, B, D, A C, A, D, D, A, D
Q:22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40
A: D, B, A, B, D, B, D, C, A, C, A, B, A, C, B, D, D, A, A
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