Bio 230 Exam 3 Questions with Correct
Answers 100%
In their 1953 paper on the double-helical structure of DNA, Watson and
Crick famously wrote: "It has not escaped our notice that the specific
pairing we have postulated immediately suggests a possible copying
mechanism for the genetic material." What did they mean? - ANSWER -Each strand in a DNA double
helix contains all the information needed
to produce a complementary partner strand.
Identify which statement(s) is/are true regarding telomere
characteristics. - ANSWER -Only statements C and D are true regarding
telomere characteristics.
Which of the following statements is not true? - ANSWER -A cell will
temporarily decondense its chromatin to silence genes during
differentiation.
Which statement is true about the association of histone proteins and
DNA? - ANSWER -Histone proteins have a high proportion of
positively charged amino acids, which bind tightly to the negatively
charged DNA backbone.
Which of the following statements about nucleosomes is false? -
ANSWER -Nucleosomes are found only in mitotic chromosomes.
How do chromatin-remodeling complexes work? - ANSWER -They
,use the energy from ATP hydrolysis to alter the arrangement of
nucleosomes, rendering certain regions of the DNA more accessible to
other proteins
In the 1920s, bacteriologist Fred Griffith demonstrated that a heat
killed, infectious pneumococcus produced a substance that could convert
a harmless form of the bacterium into a lethal one. Fifteen years later,
researchers prepared an extract from the disease-causing S strain of
pneumococci and showed that this material could transform the harmless
R-strain pneumococci cells into the infectious S-strain form. This
change to the bacteria was both permanent and heritable, suggesting that
this "transforming principle" represents the elusive genetic material of
the cells. The researchers subjected their extract to a variety of tests to
determine the chemical identity of the "transforming principle." In one
experiment, they treated the material with enzymes that destroy all
proteins. This treatment did not affect the ability of the extract to
transform harmless bacteria into an infectious form.
From this result, what c - ANSWER -The genetic material is not
protein.
What evidence suggests that the large amount of excess "junk" DNA in
a genome may serve an important function? - ANSWER -A portion of
"junk" DNA is highly conserved in its DNA sequence among many
different eukaryotic species.
One of the first steps in obtaining a karyotype (such as that shown
below of a cancer cell) is treating cells with a drug that stalls cells in
mitosis. Why must cells arrest in mitosis for karyotype analysis? -
ANSWER -Only mitotic chromosomes are highly condensed and visible
,with a light microscope.
Once heterochromatin has been established, it will often spread until it
encounters which of the following? - ANSWER -the barrier dna
sequence
In addition to its role in DNA repair, homologous recombination is also
responsible for generating genetic diversity during what process? -
ANSWER -meiosis
what does depurination refer to - ANSWER -the loss of A or G bases
from dna
at a replication fork, how is the lagging strand synthesized - ANSWER -discontinuously
which of the following best defines a mutation - ANSWER -permanent
change in a dna sequence
what generally is the fate of mutations to the genome that have harmful
consequences to an organism - ANSWER -they are usually eliminated
from the population by natural selection
the production of a continuous new strand of dna using the many
separate Okazaki fragments found on the lagging strand requires all of
the following except which one - ANSWER -dna primase
when compared to each other, the two replication forks that form at an
origin of replication move in which direction - ANSWER -in opposite
directions
what is the role of the sliding clamp during replication - ANSWER -it
keeps DNA polymerase attached to the template while the polymerase
synthesizes a new strand of dna
how does ultraviolet radiation in sunlight typically damage dna -
ANSWER -it causes two adjacent pyrimidines bases to become
, covalently linked
when dna replication proceeds along a template, which of the following
best describes the directionality of synthesis - ANSWER -in the 5 to 3
direction
at a replication fork, how is the leading strand synthesized - ANSWER -continuously
which of the following does not cause a mutation - ANSWER
evolution
what type of enzyme seals the newly added dna to the rest of the dna
molecule - ANSWER -ligase
Using your knowledge of telomerase enzyme and chromosomal size,
choose the statement that correctly describes the information in the
figure. - ANSWER -Telomerase activity would solve the end-replication
problem, as this enzyme is involved in telomere lengthening.
What potential outcomes are possible after replication in a DNA
molecule with a depurination modification that is left unrepaired? -
ANSWER -The DNA molecule is missing one nucleotide pair.
The DNA molecule contains the normal sequence.
what kinds of bonds link the two strands of a double helix to each other - ANSWER -hydrogen
nucleotides in each strand of dna are held together by what type of
bonds - ANSWER -phosphodiester
Answers 100%
In their 1953 paper on the double-helical structure of DNA, Watson and
Crick famously wrote: "It has not escaped our notice that the specific
pairing we have postulated immediately suggests a possible copying
mechanism for the genetic material." What did they mean? - ANSWER -Each strand in a DNA double
helix contains all the information needed
to produce a complementary partner strand.
Identify which statement(s) is/are true regarding telomere
characteristics. - ANSWER -Only statements C and D are true regarding
telomere characteristics.
Which of the following statements is not true? - ANSWER -A cell will
temporarily decondense its chromatin to silence genes during
differentiation.
Which statement is true about the association of histone proteins and
DNA? - ANSWER -Histone proteins have a high proportion of
positively charged amino acids, which bind tightly to the negatively
charged DNA backbone.
Which of the following statements about nucleosomes is false? -
ANSWER -Nucleosomes are found only in mitotic chromosomes.
How do chromatin-remodeling complexes work? - ANSWER -They
,use the energy from ATP hydrolysis to alter the arrangement of
nucleosomes, rendering certain regions of the DNA more accessible to
other proteins
In the 1920s, bacteriologist Fred Griffith demonstrated that a heat
killed, infectious pneumococcus produced a substance that could convert
a harmless form of the bacterium into a lethal one. Fifteen years later,
researchers prepared an extract from the disease-causing S strain of
pneumococci and showed that this material could transform the harmless
R-strain pneumococci cells into the infectious S-strain form. This
change to the bacteria was both permanent and heritable, suggesting that
this "transforming principle" represents the elusive genetic material of
the cells. The researchers subjected their extract to a variety of tests to
determine the chemical identity of the "transforming principle." In one
experiment, they treated the material with enzymes that destroy all
proteins. This treatment did not affect the ability of the extract to
transform harmless bacteria into an infectious form.
From this result, what c - ANSWER -The genetic material is not
protein.
What evidence suggests that the large amount of excess "junk" DNA in
a genome may serve an important function? - ANSWER -A portion of
"junk" DNA is highly conserved in its DNA sequence among many
different eukaryotic species.
One of the first steps in obtaining a karyotype (such as that shown
below of a cancer cell) is treating cells with a drug that stalls cells in
mitosis. Why must cells arrest in mitosis for karyotype analysis? -
ANSWER -Only mitotic chromosomes are highly condensed and visible
,with a light microscope.
Once heterochromatin has been established, it will often spread until it
encounters which of the following? - ANSWER -the barrier dna
sequence
In addition to its role in DNA repair, homologous recombination is also
responsible for generating genetic diversity during what process? -
ANSWER -meiosis
what does depurination refer to - ANSWER -the loss of A or G bases
from dna
at a replication fork, how is the lagging strand synthesized - ANSWER -discontinuously
which of the following best defines a mutation - ANSWER -permanent
change in a dna sequence
what generally is the fate of mutations to the genome that have harmful
consequences to an organism - ANSWER -they are usually eliminated
from the population by natural selection
the production of a continuous new strand of dna using the many
separate Okazaki fragments found on the lagging strand requires all of
the following except which one - ANSWER -dna primase
when compared to each other, the two replication forks that form at an
origin of replication move in which direction - ANSWER -in opposite
directions
what is the role of the sliding clamp during replication - ANSWER -it
keeps DNA polymerase attached to the template while the polymerase
synthesizes a new strand of dna
how does ultraviolet radiation in sunlight typically damage dna -
ANSWER -it causes two adjacent pyrimidines bases to become
, covalently linked
when dna replication proceeds along a template, which of the following
best describes the directionality of synthesis - ANSWER -in the 5 to 3
direction
at a replication fork, how is the leading strand synthesized - ANSWER -continuously
which of the following does not cause a mutation - ANSWER
evolution
what type of enzyme seals the newly added dna to the rest of the dna
molecule - ANSWER -ligase
Using your knowledge of telomerase enzyme and chromosomal size,
choose the statement that correctly describes the information in the
figure. - ANSWER -Telomerase activity would solve the end-replication
problem, as this enzyme is involved in telomere lengthening.
What potential outcomes are possible after replication in a DNA
molecule with a depurination modification that is left unrepaired? -
ANSWER -The DNA molecule is missing one nucleotide pair.
The DNA molecule contains the normal sequence.
what kinds of bonds link the two strands of a double helix to each other - ANSWER -hydrogen
nucleotides in each strand of dna are held together by what type of
bonds - ANSWER -phosphodiester
