Principles of Biology I
Exam IV Sample
1.
The sequence of nucleotides to which a repressor protein binds (e.g.
in the lac or trp operons) is called a/an:
a.
b.
c.
d.
e.
2.
3.
The ribozymes and the associated proteins which function to help
splice out the intervening sequences from primary RNA transcripts
(newly made RNAs) in eukaryotes are called:
a.
restriction endonucleases.
b.
recombinases.
c.
translocases.
d.
splicesomes.
e.
ribonucleases.
The codon 5’-UAA-3’ is read by the “A” site of the ribosome as:
4.
5.
promoter.
operator.
enhancer.
CAP site.
None of the above is the correct answer.
a.
stop (end of protein).
b.
the amino acid methionine.
c.
start (a new protein here).
d.
an amino acid that is not methionine.
e.
translocate to the “A” site.
Which of the following is NOT true of eukaryotic messenger RNA
molecules ready for translation in the cytoplasm?
a.
They often contain the coding sequences for 2 or more
proteins.
b.
They are commonly monocistronic.
c.
All introns have been removed.
d.
They have a have a poly A tail at the 3' end.
e.
All of the above statements are true.
An example of a genetic element (small circular DNA replicon) common
in prokaryotes, which often naturally carries useful but generally
not essential genes (such as antibiotic resistance genes) and is
frequently used in recombinant DNA/biotechnology as a cloning
vehicle is a/an:
6.
7.
8.
a.
operon.
b.
intron.
c.
plasmid.
d.
replicon.
e.
bacteriophage.
Most of the exceptions to the “universality” of the genetic code
have been found to occur in:
a.
genes in bacteria.
b.
eukaryotic nuclear encoded genes only.
c.
organelle genomes.
d.
oncogenes.
e.
None of the above are correct answers.
Enzymes which cut DNA duplexes, but only a specific nucleotide
sequences, and which are commonly used in DNA cloning experiments
are:
a.
primases.
b.
PCRs.
c.
restriction endonucleases (restriction enzymes).
d.
reverse transcriptase.
e.
far too picky about their substrates.
Which of the following properties is not shared by RNA polymerases
and DNA polymerases?
a.
carry out proofreading
b.
make the polynucleotide product in a 5Õ to 3Õ direction
c.
use nucleotide triphosphates as substrates
d.
are found in the nuclei of eukaryotic cells
e.
9.
10.
11.
12.
require a template
Normal eukaryotic genes which can, if properly mutated, act in a
dominant fashion to cause a cell to become transformed (tumor
producing) are called:
a.
oncogenes.
b.
protooncogenes.
c.
retroviruses.
d.
transforming principles.
e.
tumor suppressors.
A constitutive gene is one that is:
a.
expressed at a constant rate at all times.
b.
inducible by a specific small molecule.
c.
repressible by a specific small molecule.
d.
controlled by an operator sequence near the promoter.
e.
under positive regulation (such as by the CAP protein).
The nucleotide sequence in DNA recognized by an RNA polymerase which
indicates that this location is the start of a gene/operon (a
transcription unit if you prefer) and to which the RNA polymerase
binds is called a/an:
a.
operator.
b.
RBS.
c.
promoter.
d.
replicon.
e.
protogene.
The TATA box in E. coli (prokaryotes) is found:
a.
at -10 with respect to the +1 (mRNA start) of the operon.
b.
at -35 with respect to the +1 (mRNA start) of the operon.
c.
at -10 with respect to the first AUG codon.
d.
at the operator.
e.
13.
14.
15.
at transcriptional terminators.
The small molecule which "inactivates" the lac operon repressor,
causing it to be unable to bind to the appropriate regulatory site
of the operon is:
a.
tryptophan.
b.
ATP.
c.
lactose/allolactose.
d.
methionine.
e.
cAMP (cyclic AMP).
Which of the following is following is not commonly used in cloning
procedures (the cloning of recombinant DNA molecules)?
a.
restriction endonucleases
b.
plasmids
c.
DNA ligase
d.
RNA polymerase
e.
All of the above are commonly used in cloning procedures.
Eukaryotic nucleotide sequences which are eliminated from the
initial RNA transcript (by RNA processing or splicing) to produce a
final mRNA ready for translation are called:
a.
exons.
b.
operons.
c.
endonucleases
d.
promoters.
e.
introns.
16.
In the diagram of the lac operon shown below, which letter
indicates the approximate location of the operon’s repressor binding
site?
17.
The triplet of nucleotides (such as CAU) in a tRNA which pairs with
the mRNA triplet coding for a specific amino acid is referred to as:
18.
a.
an anticodon.
b.
a ribosome binding site.
c.
a frameshift.
d.
a codon.
e.
promoter.
In the presence of lactose only (sole carbon source available to
cells), expression of the lac operon in E. coli:
a.
is fully turned on.
b.
is completely shut down.
c.
is turned on but only at a low level.
d.
occurs only if the cells are rapidly dividing.
e.
reduces the simultaneous expression of unnecessary glycolytic
enzymes.
19.
20.
21.
In the presence of glucose only, the lac operon of E. coli would be
expected to be:
a.
turned on at a high level.
b.
turned on, but only at a relatively low level.
c.
completely shut down.
d.
sporadically turned off and on, depending upon the cAMP level.
e.
turned on, but only as long as the cAMP levels remain high.
Anabolic operons (operons which encode anabolic pathways such as the
trp operon) are commonly regulated by:
a.
a repressor protein and the pathway’s substrate.
b.
a repressor protein and the pathway’s product
c.
CAP protein.
d.
Answers “a” and “c” are both correct.
e.
Answers “b” and “c” are both correct.
The first amino acid utilized in the synthesis of nearly all
proteins is:
22.
23.
24.
25.
a.
lysine.
b.
tryptophan.
c.
arginine.
d.
glycine.
e.
methionine.
A type of DNA damage commonly caused by exposing cells to
ultraviolet light is/are:
a.
double strand breaks.
b.
base analogs
c.
missing bases (fall out)
d.
pyrimidine dimers
e.
None of the above are commonly caused by ultraviolet light.
A gene or series of genes/operons,encoding catabolic pathway
enzymes, which can be turned off and on as needed are likely to have
their expression regulated in a/an __________ fashion (e.g. lac
operon in E. coli):
a.
constitutive.
b.
essential.
c.
repressible.
d.
inducible.
e.
None of the above is correct.
Which of the following does not occur in eukaryotic cells?
a.
poly(A) tails on mRNA molecules.
b.
capping on the 5’end of mRNA molecules
c.
introns
d.
exons
e.
All of the above are commonly found in eukaryotic cells.
The nucleotide triplet UGA in the ÒAÓ site of a ribosome is
recognized/read by:
26.
27.
28.
a.
a protein releasing factor.
b.
EF2.
c.
a tRNA with the corresponding triplet AUU to pair with it.
d.
an initiation factor.
e.
an initiator methionine tRNA.
Nucleotide sequences which remain in eukaryotic mRNAs after the
primary transcripts (or pre-mRNAs) are processed are encoded by:
a.
caps.
b.
exons.
c.
cistrons.
d.
primers.
e.
introns.
A process that uses primers, thermostable DNA polymerase and
heating to amplify a DNA segment many times (millions-fold) is
called:
a.
recombinant DNA.
b.
cloning.
c.
Northern blotting.
d.
gene therapy.
e.
PCR.
Which of the following statements about protein synthesis is NOT
true (i.e. is FALSE)?
a.
Amino acids/peptides are transferred from the tRNA in the
"P" site to the tRNA in the "A" site.
b.
The enzyme which moves the peptidyl tRNA from the "A" site
to the "P" site is called translocase (EF2 in humans).
c.
tRNA molecules carrying the "new" amino acid enter the "A"
site first.
29.
d.
Although protein synthesis in eukaryotic and prokaryotic cells
is generally similar, the subtle differences are often
utilized to specifically target many common antibiotics
against prokaryotes.
e.
All of the above statements are true.
Lactose (or allolactose for the scientifically pure at heart), in
the context of the E. coli lac operon, is called a/an:
30.
31.
32.
a.
inducer.
b.
operator.
c.
operon.
d.
promoter.
e.
corepressor.
cAMP levels in E. coli cells RISE when:
a.
protein synthesis rates are high.
b.
many good carbon sources are readily available.
c.
glucose is available in adequate amounts.
d.
ATP levels fall.
e.
lactose is added to the growth medium.
The nucleotide sequence in the tRNA molecule which binds to the
mRNA triplet calling for an amino acid is called a/an:
a.
anticodon.
b.
codon.
c.
elongation factor.
d.
releasing factor.
e.
aminoacyl tRNA synthetase.
The one type of RNA which virtually never requires processing before
it can function in a proper manner (be used if you prefer) is:
a.
rRNAs.
b.
snRNAs.
33.
34.
35.
36.
c.
eukaryotic mRNAs
d.
prokaryotic mRNAs
e.
prokaryotic tRNAs
The CAP protein of E. coli is an example of a/an:
a.
RNA polymerase.
b.
repressor protein.
c.
positive acting regulator protein.
d.
inducer.
e.
ribosomal protein.
In the presence of glucose and lactose, the lac operon of E. coli
would be expected to be:
a.
turned on at a high level.
b.
turned on, but only at a relatively low level.
c.
completely shut down.
d.
sporadically turned off and on, depending upon the cAMP level.
e.
turned on high, but only until the lactose is exhausted.
An example of a eukaryotic DNA element which is used to activate
genes and which can turn genes ON to a very high level even
over a great distance is a/an:
a.
TATA box.
b.
inducer.
c.
enhancer.
d.
-10/-35 region.
e.
coinducer.
Genes which tend to act against (counteract) the transforming
affects of cancer causing genes/alleles are called:
a.
operons.
b.
protooncogenes.
37.
38.
39.
40.
c.
replicons.
d.
inducible genes.
e.
tumor suppressors.
Recessive genes often involved in the transformation of cells to
tumors and often involved in inherited risk for cancer are called:
a.
oncogenes.
b.
protooncogenes.
c.
tumor initiators.
d.
transforming principles.
e.
tumor suppressor genes.
Which of the following is NOT commonly found in many eukaryotic
promoters?
a.
GC box(s)
b.
CAAT box(s)
c.
TATA box
d.
enhancer
e.
All of the above are commonly found associated with many
eukaryotic promoter regions.
A helix-turn-helix motif is commonly found in:
a.
promoter regions.
b.
tRNAs.
c.
translocase.
d.
RNA polymerases.
e.
transcription factors and repressors.
The genetic code has a total of ________ different possible codons
which call for amino acids:
a.
16
b.
20
41.
42.
43.
44.
c.
61
d.
64
e.
120
An example of a transcriptional terminator in E. coli is:
a.
AUG.
b.
UAA, UAG or UGA.
c.
a TATA box.
d.
a GC-rich stem followed by a string of uridine nucleotides
(U’s)
e.
the operator in the lac operon.
Increased greatest risk factor for lung cancer is:
a.
cigarette smoking.
b.
geographic area of residency.
c.
fat intake.
d.
air pollution in cities.
e.
diet.
____________ received the Nobel Prize for devising a method
to clone segments of DNA, making the first recombinant DNA
molecules.
a.
Watson and Crick
b.
Cohen and Boyer
c.
Sanger
d.
McClintock
e.
Messelson
____________ received the Nobel Prize for devising a method
of determining the nucleotide sequence of a segment of DNA.
a.
Watson and Crick
b.
Cohen and Boyer
c.
Sanger
d.
McClintock
e.
Messelson
45.
In the diagram of the lac operon shown below, which letter
indicates the approximate location of an inducible promoter?
46.
The enzyme which moves the ribosome along the mRNA one codon at a
time (using GTP for energy) is:
47.
48.
49.
a.
aminoacyl-tRNA synthetase.
b.
translocase.
c.
peptidyl synthetase.
d.
peptidyl transferase.
e.
reverse transcriptase.
The RNA molecule which is made by a eukaryotic RNA polymerase comes
off the DNA as a/an (it is first called):
a.
intron.
b.
exonic.
c.
cRNA.
d.
primary transcript.
e.
complementary sense strand.
The genes for the various types of alpha- and beta-globins are
examples of:
a.
pseudogenes.
b.
oncogenes.
c.
a regulon.
d.
a gene family.
e.
dispersed pseudogenes.
There can be up to 6 different codons for a single amino acid. The
proper term to describe this is to say that the genetic code is:
50.
51.
52.
a.
redundant.
b.
degenerate.
c.
proofed.
d.
duplicative.
e.
backed up.
The actual peptide bond is formed during protein synthesis through
the action of:
a.
peptidyl transferase.
b.
translocase.
c.
snRNAs.
d.
aminoacyl tRNA synthetases.
e.
anticodons.
The 3’ end of a eukaryotic mRNA almost always has:
a.
a TATA box.
b.
a ribosome binding site.
c.
a cap.
d.
an AUG sequence.
e.
a string of 200-250 A nucleotides.
A gene in a eukaryotic cell which that cell has decided that it
will never need to expressed (base upon developmental
considerations, for example) will likely be:
a.
highly methylated on the “C” bases and condensed into
heterochromatin.
b.
translocated to the X chromosome if the individual is a
female.
c.
capped.
d.
deleted.
e.
terminated.
53.
54.
Which of the following is likely contain a “zinc finger” motif?
a.
a DNA binding protein such as a transcription factor.
b.
a ribosome binding site in an mRNA.
c.
translocase and similar enzymes.
d.
reverse transcriptase.
e.
a transposable element.
Kary Mullis received the Nobel Prize in 1983 for:
a.
developing the process now known as polymerase chain reaction
(PCR).
b.
developing a process to determine the sequence of DNA.
c.
developing biochips (microarrays).
d.
discovering the first oncogene.
e.
cloning the first eukaryotic promoter.