Download DNA Questions – mahon – (26)

Version 001 – DNA Questions – mahon – (26)
This print-out should have 34 questions.
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DNA 01
001 10.0 points
What was the basis of the belief of biologists
for over two decades that proteins instead of
DNA were the genetic material?
I) Proteins are made of 20 amino acids
while DNA is made of four nucleotides;
II) Proteins have two different levels of
structural organization while DNA has
four;
III) Proteins have a greater variety of threedimensional forms than does DNA.
1. III only
2. II only
3. I and III only correct
4. I only
5. I, II and III
Explanation:
Proteins have a greater variety of threedimensional forms than does DNA and they
are made of 20 amino acids while DNA is
made of four nucleotides.
DNA 08
002 10.0 points
To prove that there is a clear correlation between DNA and genetic information some students in a science fair wanted to repeat Hershey and Chase’ experiment using labeled nitrogen instead of labeled phosphate on the assumption that there are more nitrogen atoms
in a nucleotide than phosphate.
Why will this experiment not work?
1. Meselson and Stahl already did this experiment.
2. There is no radioactive isotope of nitrogen.
1
3. Amino acids and thus proteins also have
nitrogen atoms; thus the radioactivity would
not distinguish between DNA and proteins.
correct
4. Radioactive nitrogen has a half-life of
100,000 years and the material would be too
dangerous for too long.
5. Compared to phosphate there are more
nitrogens in a nucleotide, so the latter are
more radioactive.
Explanation:
If nitrogen is labeled, the radioactivity between DNA and proteins cannot be distinguished and as such the experiment as proposed by the students would not succeed.
DNA 11
003 10.0 points
What would be the percentage of thymine in
a DNA sample if the percentage of cytosine
were 38%?
1. 38%
2. 24%
3. It cannot be determined from the information provided
4. 31%
5. 12% correct
Explanation:
The total of A, T, C and G is 100%. Since
cytosine is 38%, its complementary N-base G
will also be 38%. The remaining 24% will consist of A and T so half of this number; namely
the percentage of thymine in the sample, will
be 12.
DNA 13
004 10.0 points
Describe the kind of chemical bonds between
paired bases of the DNA double helix.
Version 001 – DNA Questions – mahon – (26)
1. sulfhydryl
2
by the live R, converting the latter to S and
killing the mouse. correct
2. hydrogen correct
3. there was no result.
3. covalent
4. phosphate
4. DNA from the live R was taken up by the
heat-killed S, converting the latter to R and
killing the mouse.
5. ionic
Explanation:
Two hydrogen bonds are found between
adenine and thymine, and three between cytosine and guanine.
DNA 22
005 10.0 points
What statement would be true if the strands
that make up DNA are antiparallel?
1. One strand is positively charged while the
other is negatively charged.
2. The 5′ to 3′ direction of one strand runs
counter to the 5′ to 3′ direction of the other
strand. correct
3. Base pairings create unequal spacing between the two DNA strands.
5. RNA from the heat-killed S was translated into proteins that killed the mouse.
Explanation:
DNA and Heredity 02
007 10.0 points
In order to show that DNA is the “transforming principle,” Avery, MacLeod, and McCarty
showed that DNA could transform nonvirulent strains of pneumococcus. Their hypothesis was strengthened by their demonstration
that
1. enzymes that destroy nucleic acids also
destroy transforming activity. correct
2. other strains of bacteria also can be transformed successfully.
4. The chromosomes are circular in shape.
3. enzymes that destroy complex carbohydrates also destroy transforming activity.
5. The twisting nature of DNA creates nonparallel strands.
4. the transforming activity is destroyed by
boiling.
Explanation:
The 5′ to 3′ direction of one strand runs
antiparallel to the 5′ to 3′ direction of the
other strand.
5. enzymes that destroy proteins also destroy transforming activity.
DNA and Heredity
006 10.0 points
In Griffith’s experiments, when heat-killed
S strain pneumococci were injected into a
mouse along with live R strain pneumococci,
DNA and Heredity 14
008 10.0 points
The base composition of DNA isolated from
a newly discovered virus is found to be 32
percent A, 17 percent C, 32 percent G, and
19 percent T. What would be a reasonable
explanation for this observation?
1. proteins released from the heat-killed S
killed the mouse.
Explanation:
1. The virus must be extraterrestrial.
2. DNA from the heat-killed S was taken up
Version 001 – DNA Questions – mahon – (26)
2. The genome of the phage must be circular,
not linear.
3
3. DNA can also act an enzyme
4. molecules are extremely long.
3. The genome of the phage is singlestranded, not double-stranded. correct
5. is transcribed into RNA and then into
proteins with specific functions. correct
4. Some of the T was converted to C during
the isolation procedure.
Explanation:
5. In some viruses, double-stranded DNA is
made up of base pairs containing two purines
or two pyrimidines.
DNA and heredity 40
011 10.0 points
During DNA replication
Explanation:
1. the template strands must separate so
that both can be copied. correct
DNA and Heredity 16
009 10.0 points
Which feature of the Watson-Crick model of
DNA structure explains its ability to function
in replication and gene expression?
1. Each strand contains all the information
present in the double helix. correct
2. Bases are exposed in the major groove of
the double helix.
3. There are structural and functional similarities between DNA and RNA.
4. The double helix is right-handed, not lefthanded.
5. DNA replication does not require enzyme
catalysts.
Explanation:
DNA and Heredity 32
010 10.0 points
Although DNA is made up of only four different bases, it can encode the information
necessary to specify the workings of an entire
organism because DNA
1. molecules are found in the nucleus.
2. is directly translated into proteins, which
are made up of 20 different amino acids.
2. the template strands come back together
after the passage of the replication fork.
3. origins of replication always give rise to
single replication forks.
4. two replication forks diverge from each
origin but one always lags behind the other.
5. one template strand must be degraded to
allow the other strand to be copied.
Explanation:
DNA and Heredity 56
012 10.0 points
The enzyme DNA ligase is required continuously during DNA replication because
1. the parental strands must be joined back
together.
2. 3’-deoxynucleoside triphosphates must
be converted to 5’-deoxynucleoside triphosphates.
3. fragments of the leading strand must be
joined together.
4. fragments of the lagging strand must be
joined together. correct
5. the complex of proteins that work together at the replication fork must be kept
Version 001 – DNA Questions – mahon – (26)
from falling apart.
Explanation:
GA SB2 02
013 10.0 points
If one strand of a DNA molecule is TACCTA, what is the sequence of the complentary
strand?
1. ATGGAT correct
2. GATCCA
3. TACCTA
4. GTAGGT
Explanation:
In DNA, A pairs with T, C pairs with G.
Holt Bio 10 05
014 10.0 points
Because the genetic code is the same in all
organisms, it appears that
1. different life-forms have different ancestors.
4
tion
3. to degrade damaged DNA molecules
4. to add nucleotides to the end of a growing
DNA strand correct
5. to rejoin the two DNA strands (one new
and one old) after replication
Explanation:
The function of DNA polymerase is to add
nucleotides to the end of a growing DNA
strand.
DNA 26
016 10.0 points
E. coli cells grown on 15 N medium and transferred to 14 N medium are allowed to grow for
two generations (two rounds of DNA replication). DNA extracted from the cells on the
second medium are then centrifuged.
What density distribution of DNA would
you expect in this experiment?
1. one low-density band
2. thymine will soon replace uracil in RNA.
2. one high-density and one low-density
band
3. the codon GUC codes for different proteins in different organisms.
3. one low-density and one intermediatedensity band correct
4. the genetic code evolved more than
once.
5. all life-forms have a common ancestor.
correct
Explanation:
Recall
DNA 19
015 10.0 points
Describe the function of DNA polymerase.
1. to seal together the broken ends of DNA
strands
2. to unwind the DNA helix during replica-
4. one intermediate density band
5. one high-density and one intermediatedensity band
Explanation:
In the Meselson-Stahl experiment, E.coli
was grown for two generations, the first on a
medium containing a heavy isotope of nitrogen 15 N and the second on a medium containing normal nitrogen 14 N. Such an experiment
should give two bands, one of intermediate
density and the other of low density, if the
DNA replication is semi-conservative.
DNA 28
017 10.0 points
Version 001 – DNA Questions – mahon – (26)
Meselson and Stahl cultured a strain of bac
terium first in a medium containing 15 N ;
thereafter they subcultured the bacterium in
a medium containing 14 N.
Consider the possible results of this experiment:
14
N DNA→
14
N−15 N→
hybrid DNA
15
5
5. unwind the parental double helix
Explanation:
The function of DNA ligase is to piece
Okazaki fragments together.
GA SB2 04
019 10.0 points
A characteristic of a DNA molecule that is
not a characteristic of a protein molecule is
that the DNA molecule
1. is composed of subunits (or monomers).
N DNA→
A
B
C
D
E
Which diagram would show the expected
result after one round of DNA replication in
the presence of 14 N?
1. A
2. B
3. E
4. D correct
5. C
Explanation:
A band of hybrid DNA, one strand consisting of N15 and the other of N14 will be found
in the middle of the tube; i.e., marked “D”.
DNA 34
018 10.0 points
What role does DNA ligase play in the elongation of the lagging strand during DNA replication?
1. join Okazaki fragments correct
2. catalyze the lengthening of telomeres
3. synthesize RNA nucleotides to make a
primer
4. stabilize the unwound parental DNA
2. is found inside cells.
3. can be very large.
4. can replicate itself. correct
Explanation:
DNA can replicate itself, whie proteins are
built from the DNA code.
GA SB2 44
020 10.0 points
After replication, each DNA molecule has
1. one strand – half old and half new.
2. two strands – both completely new.
3. two strands – one old and one new. correct
4. two strands – each strand is half old and
half new.
Explanation:
DNA is a double stranded molecule. When
DNA replicates, the DNA double strand untwists and unzips, so both old strands are
separated from each other. When nucleotides
pair up to form new DNA molecules, each
DNA molecule is made of one old strand and
one new strand.
GA SB2 01
021 10.0 points
During protein synthesis, the amino acid se-
Version 001 – DNA Questions – mahon – (26)
6
quence is determined by the
1. genetic code in the DNA molecule. correct
2. ATP produced by mitochondria.
3. signals sent by the plasma membrane.
4. speed at which translation occurs.
5. number of mitochondria in the cell.
Explanation:
The DNA code (or order of nucleotide ”letters” A, T, C, and G) codes for the order of
amino acids to make proteins for the cell.
GA SB2 34
022 10.0 points
The complementary mRNA sequence for the
DNA sequence GAACCT is
1. GAACCU.
2. GAACCT.
3. CUUGGA. correct
4. CTTGGA.
Explanation:
mRNA will have complementary base pairs
to DNA: A with T, U with A, C with G, and
G with C. Remember that RNA has uracil
(U) instead of thymine (T).
GA SB2 45
023 10.0 points
The mRNA receives information from DNA
by
1. accepting proteins through the nuclear
membrane pores.
2. making an exact copy of both strands of
the DNA molecule.
3. joining with its complementary bases on
a single DNA strand. correct
4. joining with the two DNA strands and
forming a triple helix.
Explanation:
mRNA pairs up nucleotides with only one
of the strands of DNA, called the template
strand.
Holt Bio 10 06
024 10.0 points
During transcription, the genetic information
for making a protein is encoded as a molecule
of
1. transfer RNA.
2. messenger RNA. correct
3. ribosomal RNA.
4. translation RNA.
Explanation:
Raven15 54
025 10.0 points
Transcription is the first stage in the Central
Dogma and is initiated by
1. mRNA polymerase binding to a site
known as the promoter.
2. RNA polymerase binding to a site known
as the initiator.
3. RNA polymerase binding to a site known
as the promoter. correct
4. DNA polymerase binding to a site known
as the promoter.
5. tRNA polymerase binding to a site known
as the promoter.
Explanation:
Recall
Raven15 64
026 10.0 points
RNA splicing in eukaryotic cell protein syn-
Version 001 – DNA Questions – mahon – (26)
thesis means that the product of translation
called the
7
3. None of these
4. rRNA
1. secondary transcript does not sufficiently
explain RNA splicing.
2. primary transcript is cut and put back
together to produce the mature mRNA transcript. correct
3. secondary transcript is cut and put back
together to produce the mature tRNA transcript.
4. primary transcript is cut and put back
together to produce the mature tRNA transcript.
Explanation:
Recall
Starr 14 06
027 10.0 points
A mature messenger RNA
1. leaves the nucleus and carries out its function in the cytoplasm.
2. contains a sequence of triplet codons that
specify amino acids.
3. All of these correct
4. has no introns.
5. occurs in very small amounts compared
to the total RNA.
Explanation:
Recall
Starr 14 18
028 10.0 points
What class of RNA binds free amino acids
and carries them to ribosomes?
1. tRNA correct
2. All of these
5. mRNA
Explanation:
Recall
StarrW 13 05
029 10.0 points
Each codon calls for a specific
1. polypeptide.
2. amino acid. correct
3. lipid.
4. protein.
5. carbohydrate.
Explanation:
Recall
GA SB2 15
030 10.0 points
The function of messenger RNA (mRNA) is
to
1. prevent DNA mutations during replication.
2. translate the base sequence at the ribosomes.
3. make a copy of the DNA instructions and
bring it to the ribosome. correct
4. carry amino acids to the ribosome.
Explanation:
mRNA travels from the nucleus to the ribosome with the DNA instructions for building
proteins.
GA SB2 08
031 10.0 points
The information that controls the production
of proteins in a cell must pass from the nucleus
Version 001 – DNA Questions – mahon – (26)
to the
8
Explanation:
Recall
1. cell membrane.
2. mitochondria.
3. chloroplasts.
4. ribosomes. correct
Explanation:
Ribosomes take information from mRNA
(which came from DNA in the nucleus) to
construct the protein.
Raven15 24
032 10.0 points
The majority of amino acids have a specific
tRNA molecule that transports it to the site
of protein synthesis. Therefore, in humans the
number of different tRNA molecules would be
at least
1. thousands.
2. 40.
3. 3.
4. 80.
5. 20. correct
Explanation:
Raven15 39
033 10.0 points
The bond that forms between the newly
added amino acid and the previous amino
acid on the chain is called a
1. hydrogen bond.
2. hydrophobic bond.
3. hydrophilic bond.
4. phosphodiester bond.
5. peptide bond. correct
Raven15 50
034 10.0 points
If the DNA triplet code were ATG-CGT, the
tRNA anticodons would be
1. UACGCA
2. UAGCGU
3. ATGCGT
4. TGCGTA
5. AUGCGU correct
Explanation:
The DNA is transcribed into mRNA which
reads UACGCA. The anticodon needed to
pair with this would be AUGCGU.