Download Biology 303 EXAM II 3/14/00 NAME

BIOL. 303 EXAM III 4/19/07
Name_____________________________
------------------------------------------------------------------------------------------------------------------This exam consists of 40 multiple choice questions worth 2.5 points each. On
the separate testing form, please fill-in the single best choice for each question. Be
sure to fill-out your student number and name on the answer sheet. Good luck!
---------------------------------------------------------------------------------------------------------------------1.
In 1964, Nirenberg and Leder used the triplet binding assay to determine specific
codon assignments. A complex of which of the following components was trapped on
the nitrocellulose filter?
1.
2.
3.
4.
2.
ribosomes and DNA
charged tRNA, RNA triplet, and ribosome
free tRNAs
uncharged tRNAs and ribosomes.
AUG is almost always the:
1. intron
2. exon
3. anticodon
4. initiation codon
3.
Peptidyl transferase is associated with the action of the:
1. ribosome
2. template strand
3. nucleus
4. cytoplasm
4.
Transcribed regions present in the mature mRNA would arise from a(n)
________, while transcribed regions NOT present in the mature mRNA would arise
from a(n) ________.
1.
2.
3.
4.
intron; exon
exon; intron
codon; anticodon
anticodon; codon
5.
Ribosomes are composed of:
1. tRNA and protein
2. mRNA and protein
3. rRNA and protein
4. proteins only
6.
Which of the following is not true of tRNA?
1. it contains modified bases
2. it contains thymine
3. it has secondary structure
4. it has anticodon loop
7.
A defect in aminoacyl-tRNA synthetase would directly lead to:
1. a block in transcription
2. uncharged tRNA
3. 1 & 2
4. none of the above
8.
What property of the genetic code allows the use of several codons for a
particular amino acid?
1. near universality
2. degeneracy
3. non-overlapping codons
4. reading frame
9.
By their experimentation using auxotroph mutants of the Neurospora fungus,
Beadle and Tatum were able to propose the hypothesis that:
1. prototrophs will grow only if provided with nutritional supplements.
2. several different enzymes may be involved in the same step in a biochemical
pathway.
3. the role of a specific gene is to produce a specific enzyme.
4. more than one codon can specify a given amino acid.
10.
Consider the pathway shown below for the synthesis of the amino acid arginine
in Neurospora. ARG-F, G, and H are the names of the genes controlling the steps of
the pathway:
ornithine
ARG-F
→
citrulline
ARG-G
→
ARG-H
succinate
→
arginine
Mutant strains of Neurospora are grown in minimal media with supplements as follows.
Each mutant strain carries only a single mutation. Growth is shown by (+), no growth is
shown by (0):
mutant strain
a
b
c
nothing
0
0
0
___
ornithine
0
0
0
Supplements__________________
citrulline succinate
arginine
0
0
+
0
+
+
+
+
+
Which is statement is correct?
1. strain a is defective in ARG-G
2. strain a is defective in ARG-F
3. strain b is defective in ARG-G
4. strain c is defective in ARG-H
11.
In the lac operon, under which of the following conditions will the lac genes be
transcribed at high levels?
1.
2.
3.
4.
12.
low glucose, low lactose
high glucose, low lactose
low glucose, high lactose
high glucose, high lactose
RNA polymerase binds to the:
1.
2.
3.
4.
operator
promoter
repressor
inducer
13.
For the E. coli genotype I+P+OcZ+Y+A+, the expression of β-galactosidase will be:
1. inducible
2. constitutive
3. absent
4. none of the above
14.
The lac operon
1. is under negative and positive control.
2. is under positive control only.
3. is normally expressed constitutively.
4. is an example of tissue-specific expression.
15.
With regards to the trp operon,
1. tryptophan is an inducer.
2. tryptophan is a co-repressor.
3. attenuation can halt replication.
4. none of the above.
16.
Under the system of genetic control of the trp operon,
1. when there are high levels of tryptophan in the medium, transcription of the
trp operon occurs at high levels.
2. when there is no tryptophan in the medium, transcription of the trp operon
occurs at high levels.
3. when there are high levels of tryptophan in the medium, transcription of CAP
occurs at high levels.
4. when there are high levels of tryptophan in the medium, ribosomes “stall” and
reduce the levels of tryptophan synthesized.
17.
Regarding the trp operon in B. subtilis, TRAP influences gene expression
1.
2.
3.
4.
at the transcriptional level.
at the translational level.
both 1 and 2
none of the above
18.
In the absence of arabinose, the AraC protein induces a regulatory secondary
structure in _________.
1. protein
2. DNA
3. mRNA
4. arabinose
19.
Three posttranscriptional modifications often seen in the maturation of mRNA in
eukaryotes are
1.
2.
3.
4.
20.
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
Protein-encoding genes in eukaryotes are transcribed by
1. RNA polymerase I
2. RNA polymerase II
3. RNA polymerase III
4. RNA polymerase IV
21.
Transcription factors act as_________.
1. cis-acting regulatory elements
2. trans-acting regulatory elements
3. promoters
4. enhancers
22.
SWI-SNF proteins are involved in:
1.
2.
3.
4.
basal transcription
RNA interference
repression
chromatin remodeling
23.
Eukaryotic cells are able to carefully regulate precise levels of transcription in
specific genes encoding structural proteins through:
1. complex enhancer elements that can associate with multiple activator and
repressor proteins
2. production of different types of sigma factors
3. attenuation
4. all of the above
24.
Which of the following methods of regulation is not present in prokaryotes?
1.
2.
3.
4.
DNA-binding proteins
attenuation
repressor proteins
chromatin remodeling
25.
What modification neutralizes the charges on histones and loosens up the
interactions between histones and DNA?
1. phosphorylation
2. methylation
3. acetylation
4. polyadenylation
26.
Which of the following can account for multiple proteins from a primary
transcript?
1. alternative splicing
2. reverse transcription
3. 5' methylation
4. polyribosomes
27.
The term "chromatin remodeling" refers to
1. alteration of chromatin structure in association with transcription.
2. a process that only bacteria perform since they contain no nucleus.
3. a process that is exclusively associated with transcription by RNA polymerase
III in eukaryotes.
4. alteration in chromatin structure to facilitate loading and translation by
ribosomes and, thus, enhance gene expression.
28.
The phenomenon known as “RNAi” (RNA interference) can be used
experimentally to
1.
2.
3.
4.
reduce expression of a specific target gene.
reduce transcription rate from a specific gene promoter.
interfere with replication.
enhance gene expression.
29.
Controls that tie the integrity of the genome with progression through cell division
are known as:
1. growth factors
2. receptors
3. cyclins
4. checkpoints
30.
Colonization of distal sites by cancer cells is known as:
1. metastasis
2. angiogenesis
3. clonal replication
4. apoptosis
31.
Wild-type genes that can cause cancer through increased expression are:
1. tumor suppressor genes
2. proto-oncogenes
3. CDK inhibitors
4. nonexistent
32.
Wild-type genes that can cause cancer through a loss-of-function mutation are:
1.
2.
3.
4.
tumor suppressor genes
oncogenes
proto-oncogenes
cyclin-dependent kinases
33.
Sporadic cancer arises from __________; familial cancer arises from
_________.
1. somatic mutations; germline mutations
2. somatic mutations; germline and somatic mutations
3 .germline mutations; somatic mutations
4. germline mutations; stem cell mutations
34.
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?”
1. p34
2. p102
3. cyclin
4. p53
35. A person born with an inherited predisposition to cancer usually does not develop
cancer until after
1.
2.
3.
4.
exposure to radiation.
LOH of the inherited mutation.
age 70
Mardis Gras
36.
Regarding the relationship between viruses and cancer, which statement is most
accurate?
1. viruses cause some cancers in animals, but viruses are not associated with
cancer in humans.
2. most human cancers are known to be caused by viruses.
3. viruses are not associated with cancer in animals or humans
4. some human cancers are closely associated with viral infection and some
cancers can possibly be prevented by vaccination against virus.
37.
What is the function of an antibiotic-resistance gene in a vector?
1. To allow resistant transformants to grow in selective medium
2. To distinguish introns from exons
3. To screen for vectors with inserts
4. To allow plasmid replication
38.
What information is present in a cDNA library?
1.
2.
3.
4.
39.
intron sequences
promoter sequences
exon sequences
telomere sequences
What is the function of dideoxynucleotides in Sanger DNA sequencing?
1. They act as primers for DNA polymerase.
2. They act as primers for reverse transcriptase.
3. They cut the sequenced DNA at specific sites.
4. They stop synthesis at a specific site, so the base at that site can be
determined.
40.
Which of the following is needed in order to amplify a DNA fragment by PCR?
1. a set of primers.
2. knowledge of the complete nucleotide sequence of the fragment to be
amplified.
3. RNA polymerase.
4. dideoxynucleotide triphosphates.
That’s all!
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