Chapter 13 MC
Nucleic acids are assembled in the _____ direction.
5' to 3'
Which of these is a difference between a DNA and an RNA molecule?
DNA is usually double-stranded, whereas RNA is usually single-stranded
A student isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. After adding some DNA to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has the student probably LEFT OUT of the mixture?
DNA ligase
What enzyme forms covalent bonds between restriction fragments?
DNA ligase
The enzyme that can replicate DNA is called _____.
DNA polymerase
What catalyzes DNA synthesis?
DNA polymerase
In E. coli, which of the following enzymes removes the RNA primer from the 5' end of the DNA fragment?
DNA polymerase I
Why is the new DNA strand complementary to the 3' to 5' strands assembled in short segments?
DNA polymerase can assemble DNA only in the 5' to 3' direction
The antiparallel arrangement of double-stranded DNA is due to the phosphate group being bonded to the 3' carbon on one strand and the 5' carbon on the complementary strand.
False
Which of the following has the greatest potential as a cancer treatment?
Find a way to turn off the gene for making telomerase in cancer cells, since the cells would stop dividing when the telomeres were gone.
Who conducted the X-ray diffraction studies that were key to the discovery of the structure of DNA?
Franklin
Which of the following is a concern expressed by opponents of the use of genetically modified (GM) food crops?
GM food crops might pass their new genes to close relatives in nearby wild areas.The protein products of transgenes in GM food crops might lead to allergic reactions in human consumers.
Who demonstrated that DNA is the genetic material of the T2 phage?
Hershey and Chase
Which of the following statements correctly describes one difference between heterochromatin and euchromatin?
Heterochromatin is highly condensed, whereas euchromatin is less compact.
Why do histones bind tightly to DNA?
Histones are positively charged, and DNA is negatively charged.
Complementary base pairing relies on the number of hydrogen bonds that each base can make.
True
In a single nucleotide, the phosphate group is attached to the 5' carbon of the sugar unit.
True
The phosphate attached to the 5' carbon of a given nucleotide links to the 3' -OH of the adjacent nucleotide
True
Archaeologists unearthed a human skull with a small dried fragment of the scalp still attached. They extracted a tiny amount of DNA from the scalp tissue. How could they obtain sufficient DNA for an analysis of the ancient human's genes?
Use the polymerase chain reaction.
What information can not be obtained from the sequence of a gene?
Whether the gene is methylated.
Which of the following statements most accurately describes transformation in bacteria?
Which of the following statements most accurately describes transformation in bacteria?
Does the distribution of bases in sea urchin DNA and salmon DNA follow Chargaff's rules?
Yes, because the %A approximately equals the %T and the %G approximately equals the %C in both species.
If Chargaff's equivalence rule is valid, then hypothetically we could extrapolate this to the combined genomes of all species on Earth (as if there were one huge Earth genome). In other words, the total amount of A in every genome on Earth should equal the total amount of T in every genome on Earth. Likewise, the total amount of G in every genome on Earth should equal the total amount of C in every genome on Earth. Calculate the average percentage for each base in your completed table. Do Chargaff's equivalence rules still hold true when you consider those six species together?
Yes, the average for A approximately equals the average for T, and the average for G approximately equals the average for C. Submit
The letter A indicates _____.
a DNA double helix
A hydroxyl is present at the 3' end of the growing DNA strand. What is at the 5' end?
a phosphate group
In recombinant DNA experiments, what is used to cut pieces of DNA and what joins the resulting fragments to form recombinant DNA?
a restriction enzyme ... DNA ligase
Many of the first responders at the Chernobyl accident died within hours or days of working at the explosion site. What were they most likely to die from, and why?
acute radiation sickness due to exposure to ionizing radiation
Researchers are studying a proposed tumor suppressor gene in fruit flies. They want to examine what happens when the gene has lower than normal expression, without inactivating the gene entirely.
dCas9 and repression domain
This is a DNA fingerprint exhibiting samples from a victim, two suspects, and the crime scene. Which of these DNA fragments is common to both the victim and Suspect 2?
c
Assume that you are trying to insert a gene into a plasmid. Someone gives you a preparation of genomic DNA that has been cut with restriction enzyme X. The gene you wish to insert has sites on both ends for cutting by restriction enzyme Y. You have a plasmid with a single site for Y but not for X. Your strategy should be to
cut the DNA again with restriction enzyme Y, and insert these fragments into the plasmid cut with the same enzyme.
Researchers want to make an endonuclease that binds to target DNA, but does not cut the DNA. This will allow them to target specific areas of the genome for other modifications without making cuts.
dCas 9
Researchers are studying a proposed oncogene in mice. They want to examine what happens when the gene is overexpressed.
dCas9 and activation domain
Researchers are studying the three-dimensional organization of genomic structure. They want to visualize the location of specific genomic loci within a living cell.
dCas9 and fluorescent protein
The elongation of the leading strand during DNA synthesis _
depends on the action of DNA polymerase
Which of the following sets of materials is required by both eukaryotes and prokaryotes for DNA replication?
double-stranded DNA, four kinds of DNA nucleotides, primers, origins of replication
After DNA replication is completed,
each new DNA double helix consists of one old DNA strand and one new DNA strand
After DNA replication is completed, _____.
each new DNA double helix consists of one old DNA strand and one new DNA strand
Which of the following functions in the regulation of gene expression?
euchromatin
After allowing phages grown with bacteria in a medium that contained 32P and 35S, Hershey and Chase used a centrifuge to separate the phage ghosts from the infected cell. They then examined the infected cells and found that they contained _____, which demonstrated that _____ is the phage's genetic material.
labeled DNA ... DNA
The new DNA strand that grows continuously in the 5' to 3' direction is called the _____.
leading strand
You briefly expose bacteria undergoing DNA replication to radioactively labeled nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA separates into two classes. One class of labeled DNA includes very large molecules (thousands or even millions of nucleotides long), and the other includes short stretches of DNA (several hundred to a few thousand nucleotides in length). These two classes of DNA probably represent
leading strands and Okazaki fragments.
Gel electrophoresis separates DNA fragments on the basis of what characteristic?
length
During DNA replication, which of the following enzymes covalently connects segments of DNA?
ligase
Short segments of newly synthesized DNA are joined into a continuous strand by _____.
ligase
In gel electrophoresis DNA molecules migrate from _____ to _____ ends of the gel.
negative ... positive
In nucleotide excision repair, damaged DNA is excised by what enzyme(s)?
nuclease
In which order do the necessary enzymes act to repair a thymine dimer by nucleotide excision repair?
nuclease, DNA polymerase, DNA ligase
The spontaneous loss of amino groups from adenine in DNA results in hypoxanthine, an uncommon base, opposite thymine. What combination of proteins could repair such damage?
nuclease, DNA polymerase, DNA ligase
Which of the following lists of structures correctly represents the order of increasingly higher levels of organization of chromatin?
nucleosome, 30-nm chromatin fiber, looped domain
What process repairs damage to a preexisting double helix?
nucleotide excision repair
Drag the basic steps of the CRISPR-Cas9 gene editing process in order.Hint: Watch the short video embedded in the paper called, "CRISPR: A word processor for editing the genome."
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Drag the labels to the table to fill in the genotypic and phenotypic ratios. Not all labels will be used.Hint: Figure 2 in the online paper illustrates the process of the MCR technology and the genetic cross outcomes observed in the research.
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Drag the labels to their appropriate locations in the probe. Labels can be used once, more than once, or not at all.
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Part A - The experimental technique: Density-gradient centrifugation
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Part B - Experimental results: Banding pattern predictions for each model of replication
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Part C - Experimental results: Banding pattern predictions after the second round of replication
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Part D - Experimental prediction: Predicting the results after additional rounds of replication
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The diagram below shows a bacterial replication fork and its principal proteins.
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E. coli cells grown on 15N medium are transferred to 14N medium and allowed to grow for two more generations (two rounds of DNA replication). DNA extracted from these cells is centrifuged. What density distribution of DNA would you expect in this experiment?
one low-density and one intermediate-density band
This is an image of a _____.
phage
1.
phosphate
The letter A indicates _____.
phosphate group
Which part of a deoxynucleoside triphosphate (dNTP) molecule provides the energy for DNA synthesis?
phosphate group
Which of the following enzymes creates a primer for DNA polymerase?
primase
What are telomeres?
regions of DNA at the end of chromosomes which do not code for making proteins
What is the function of topoisomerase?
relieving strain in the DNA ahead of the replication fork
What is the function of DNA polymerase III in replication in E. coli?
to add nucleotides to the 3' end of a growing DNA strand
Next, can you identify what the source is trying to accomplish by providing this information?As you read the post, think about what the writer's agenda might be with regard to GMOs. What seems to be the main purpose of the blog post?
to convince the public that genetic engineering is not the solution to citrus greening
Next, can you identify what the source is trying to accomplish by providing this information?As you read the article, think about what the writer's agenda might be with regard to the consumption of sugary, processed foods. What seems to be the main purpose of the news article?
to inform the public of a new study's findings about the effects of consuming excessive amounts of sugar in soda
True or false? Comparison of the sequences of the same gene across species can give some insight into the existence of a common ancestor with that gene.
true
True or false? Single-stranded DNA molecules are said to be antiparallel when they are lined up next to each other but oriented in opposite directions.
true
Researchers are studying an allele associated with a longer life span in humans, which varies from the normal variant by six base pairs. In order to study this allele in the laboratory, they want to modify the mouse homologue to have the same 6 base pair variation
Cas9 and HDR
Researchers identify some previously uncharacterized genes that might play a role in diabetes. They want to make mouse mutants with null mutations in those genes and study what symptoms arise as a result
Cas9 and NHEJ
How is the aging process linked to telomeres?
Cells with short telomeres can no longer divide, so damaged tissues cannot be repaired.
Early, flawed DNA models proposed by Watson and Crick and by Linus Pauling correctly described which property of DNA?
DNA is composed of sugars, phosphates, and bases.
Why does a new DNA strand elongate only in the 5' to 3' direction in replication?
DNA polymerase can only add nucleotides to the free 3' end.
What is the role of DNA polymerase during DNA synthesis?
DNA polymerase is the enzyme that catalyzes the addition of a nucleotide onto the 3' end of a growing DNA strand. DNA polymerase is the enzyme complex responsible for synthesizing a new strand of DNA, using an existing strand as a template.
Select the most accurate statement describing DNA replication complexes.
DNA replication complexes are grouped into factories, which are anchored to the nuclear matrix.
The -OH group on the 3' carbon of the sugar unit is the attachment site for the nitrogenous base.
False
The radioactive isotope 32P labels the T2 phage's _____.
DNA
What is this an image of?
loops
This is an image of a(n) _____
nucleotide
Which enzyme(s) will produce a DNA fragment that contains the entire vgp gene (shown in red) and has "sticky ends"?
*BamHI*HindIII
What did the structure of DNA's double helix suggest about DNA's properties?
. DNA can be replicated by making complimentary copies of each strand.2. DNA can change. Errors in copying can result in changes in the DNA sequence that could be inherited by future generations.3. DNA stores genetic information in the sequence of its bases.
A DNA molecule consists of two antiparallel strands of polynucleotides. Each strand is composed of nucleotides bound to each other along the sugar-phosphate backbone.
...
In a nucleotide, the nitrogenous base is attached to the sugar's _____ carbon and the phosphate group is attached to the sugar's _____ carbon.
1' ... 5'
DNA fragment B consists of _____ base pairs.
1,405
The following figure shows the general steps that occur when a researcher uses the CRISPR-Cas9 system to modify a protein-encoding gene in a eukaryotic cell with the goal of modifying the protein product. Drag the descriptions of the steps to their appropriate locations on the figure.
1. Create plasmid expression vectors with genes encoding Cas9 and sgRNA. 2. Introduce the vectors into a eukaryotic cell. 3. The gene expression machinery of the cell produces the Cas9 protein and the sgRNA. 4. The Cas9 protein, guided by sgRNA, binds to its target sequence in the cell's DNA. 5. The Cas9 protein cleaves the target sequence. 6. During the process of DNA break repair, the target sequence may be modified. 7. The modified DNA sequence is transcribed into RNA. 8. The RNA is translated into a modified protein.
Finally, how can you use your assessment of the authority, motivation, and reliability of the information to evaluate this web site relative to other sources? Use the scales below to assign a numerical score to this source.Assign a numerical score for each category. Then add up the total score. (The highest possible score is 6; the lowest is 0.) In what range does this source fall?
2 to 4
What materials does DNA polymerase require in order to synthesize a complete strand of DNA?
3'-OH end of the new DNA strand Single-stranded DNA template All four deoxyribonucleotides triphosphates (containing A, C, T, or G)
How many DNA molecules would there be after four rounds of PCR if the initial reaction mixture contained two molecules?
32
Hershey and Chase used _____ to radioactively label the T2 phage's proteins.
35S
Given a template strand of 3'-ATGCTTGGACA-5' and a partially-made complementary strand containing only 5'-TAC-3', what would be the sequence of the new strand of DNA (including the 5'-TAC-3') if the only additional nucleotides available to DNA polymerase were those containing the bases G, A, and C?
5'-TACGAACC-3'
In this example the marker DNA includes fragments that have 23,130, 9,416, 6,557, 4,361, 2,322, 2,027, and 564 base pairs. Approximately how many base pairs are in the DNA fragment indicated by the letter A?
6557
Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?
8%
Use Chargaff's rules to predict the missing values for E. coli, human, and ox DNA. Round your answers to the nearest whole number.
:)
4.
A
Where would RNA polymerase attach?
A
In an analysis of the nucleotide composition of DNA, which of the following will be found in a given DNA molecule?
A + C = G + T
In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules?
A + G = C + T
Why is it so important to be able to amplify DNA fragments when studying genes?
A gene may represent only a very small portion of the cell's DNA.
What is the polymerase chain reaction (PCR)?
A method to amplify a fragment of DNA.
Check each of the true statements about the proteins involved in cutting and pasting DNA. More than one statement may be true.
A restriction enzyme cuts DNA while DNA ligase pastes DNA. A particular restriction enzyme only cuts DNA at one very specific DNA sequence. DNA ligase pastes together segments of DNA with matching sticky ends.
Which of the following sequences in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme?
AAAA TTTT
The sticky end of the DNA restriction fragment shown here will pair with a DNA restriction fragment with the sticky end ____
ACGT
For a science fair project, two students decided to repeat the Hershey and Chase experiment, with modifications. They decided to label the nitrogen of the DNA rather than the phosphate. They reasoned that each nucleotide has only one phosphate and two to five nitrogens. Thus, labeling the nitrogens would provide a stronger radioactive signal than labeling the phosphates. Why won't this experiment work?
Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.
The new mutagenic chain reaction (MCR) technology uses the CRISPR-Cas9 gene editing system to simultaneously mutate the same gene on both chromosomes. This technique has many potential applications for short- and long-term research. Select all the short- and long-term applications of this new tool.Hint: Turn on the "Results and conclusions" and "Connect to learning standards" learning lenses and scan the highlighted portions of the article.
Applicable to global health, particularly in disease vector and pest population research Increased efficiency of a disease-specific delivery system for gene therapy strategies Acceleration of genome engineering research timelines Applicable to different model systems in a vast array of situations
What is the %T in wheat DNA?
Approximately 28%
Finally, how can you use your assessment of the authority, motivation, and reliability of the information to evaluate this web site relative to other sources? Use the scales below to assign a numerical score to this source.
Assign a numerical score for each category. Then add up the total score. (The highest possible score is 6; the lowest is 0.) In what range does this source fall?
In the accompanying image, a nucleotide is indicated by the letter _____.
B
The segment of DNA shown in the figure above has restriction sites I and II, which create restriction fragments A, B, and C. Which of the gels produced by electrophoresis shown below best represents the separation and identity of these fragments?
B
Which one restriction enzyme satisfies all three of the requirements listed above?
BamHI only
Which enzyme(s) would cut the plasmid without disrupting the function of the ampR gene?
BamHI, EcoRI, and HaeIII
Which enzyme(s) would produce sticky ends when cutting both the human DNA and the plasmid?
BamHI, EcoRI, and HindIII
Which enzyme(s) would cut the human DNA shown in Part A on both sides of the vgp gene, but not inside the gene?
BamHI, HaeIII, and HindIII
A nitrogenous base is indicated by the letter ____
C
In which image will adenine (A) be the next nucleotide to be added to the primer?
C
Which of these is(are) pyrimidines?
C, D, and E *Pyrimidines are single-ring structures
We may never know how many people became ill or died as a result of the Chernobyl accident. What is the main reason why this is so difficult to determine?
Cancer might not occur for many years after exposure to ionizing radiation.
In the 1950s, when Watson and Crick were working on their model of DNA, which concepts were well accepted by the scientific community?
Chromosomes are made up of protein and nucleic acid.Chromosomes are found in the nucleus.Genes are located on chromosomes.
Duplication of chromosomes occurs during S phase of the cell cycle. Duplication requires the separation of complementary DNA strands to allow for DNA replication. Which of the following statements best explains how weak hydrogen bonds function better in this situation than stronger bonds would?
Complementary DNA strands are separated or "unzipped" for the replication process. Weak hydrogen bonds between complementary strands are easily disrupted during DNA replication because they are not high-energy chemical bonds.
In the late 1950s, Meselson and Stahl grew bacteria in a medium containing "heavy" (radioactive) nitrogen (15N) and then transferred them to a medium containing 14N, which is a nonradioactive form of nitrogen. They then extracted DNA from the bacteria and centrifuged it to separate the DNA of different densities. Which of the results in figure above would be expected after one round of DNA replication in the presence of 14N?
D
Suppose you are provided with an actively dividing culture of Escherichia coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?
DNA in both daughter cells would be radioactive.
What did Rosalind Franklin's famous photo 51 show?
DNA is a helix.
What are chromosomes made of?
DNA and proteins
In trying to determine whether DNA or protein was the genetic material, Hershey and Chase made use of which of the following facts about these two types of molecules?
DNA contains phosphorus, whereas protein does not.
Meselson and Stahl cultured E. coli for several generations in a medium with a heavy isotope of nitrogen, 15N. They transferred the bacteria to a medium with a light isotope of nitrogen, 14 N. After two rounds of DNA replication, half the DNA molecules were light (both strands had 14N) and half were hybrids (15N-14N). What did the researchers conclude from these results?
DNA replication is semiconservative.
During DNA replication, the leading strand is synthesized continuously, whereas the lagging strand is synthesized as Okazaki fragments. Why is this so?
DNA synthesis can take place only in the 5' to 3' direction.
What is the basis for the difference in how the leading and lagging strands of DNADNA molecules are synthesized?
DNADNA polymerase can join new nucleotides only to the 3′3′ end of a preexisting strand, and the strands are antiparallel.
After replication is complete, the new DNAs, called _____, are identical to each other.
Daughter DNA
Which of these DNA molecules is the shortest?
E(The shorter the DNA molecule, the farther it moves.)
DNA replication is said to be semiconservative. What does this mean?
Each new double helix consists of one old and one new strand
What steps could help refine the researchers' experiment to modify only the two target genes? Select all that apply.
Engineer a version of Cas9 that demonstrates higher fidelity to the target sequence. Screen the rest of the mouse genome to be sure the 20-be targets do not appear elsewhere in the genome.
Nucleotides are added to a growing DNA strand as nucleoside triphosphates. What is the significance of this fact?
Hydrolysis of the two phosphate groups (P-Pi) and DNA polymerization are a coupled exergonic reaction.
Might there be an evolutionary advantage of this ability? Explain.
If the frequency of mutations increases, so does the probability of adaptations to new conditions. Thus, this species is more likely to survive.
Which of the following statements best describes the eukaryotic chromosome?
It consists of a single linear molecule of double-stranded DNA plus proteins.
Which of the following is true of DNA during interphase?
It exists as chromatin and is less condensed than mitotic chromosomes.
Why is ionizing radiation damaging to cells?
It knocks the electrons from the cell's molecules, forming ions and breaking bonds.
What is the function of helicase in DNA replication?
It untwists the double helix and separates the two DNA strands.
The concrete sarcophagus enclosing the damaged reactor is crumbling, allowing radiation to leak out into the environment. An animation of a new protective cover is shown in the video. Why hasn't the construction of this cover been completed?
It will be extremely expensive to build.
In the early 1950s, many researchers were racing to describe the structure of DNA using different approaches. Which of the following statements is true?
Jim Watson and Francis Crick built theoretical models, incorporating current knowledge about chemical bonding and X-ray data.
Drag each phrase to the appropriate bin depending on whether it describes the synthesis of the leading strand, the synthesis of the lagging strand, or the synthesis of both strands.
Leading strand: made continuously, daughter strand elongates toward replication fork, only one primer needed Lagging strand: made in segments, daughter strand elongates away from replication fork, multiple primers needed Both strands: synthesized 5' to 3'
CH 11
MC
In his transformation experiments, which of the following results did Griffith observe?
Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form.
Complete the following sorting exercise to be sure you understand how the two break repair mechanisms are similar and different. Sort each item to the appropriate bin.
NHEJ Repair ONLY 1. More error-prone; likely to cause indels and frame shift mutations. 2. Often results in nonfunctional (null) mutants. 3. Simply involves ligation of broken DNA fragments. HDR repair ONLY 1. Better for making complex substitutions. 2. Increases in frequency after single-strand breaks. 3. Ses an underaged homologous chromosome as a template. Both NHEJ and HDR Repair 1. Occurs after a DNA break (including breaks made by Cas9).
Will only grow in medium without ampicillin
No plasmid
Which of the following problems during DNA replication is being illustrated with the kids in the video?
Nucleotides at the ends of the DNA strands are lost when DNA replicates.
Select all the bioethical concerns surrounding the use of MCR technology specifically and CRISPR-Cas9 systems in general.Hint: Select the "Results and conclusions" and "Connect to learning standards" learning lenses and scan the highlighted regions of the article. Also, watch the final video linked in the paper.
Off-target effects (edits in the wrong place) leading to adverse genetic changesUnintentional release of MCR organisms into the environmentEquity issues related to availability of the technology to all people based on economic meansIntentional misuse of the technologyPurposely changing the genome of human germ cell lines (leading to eggs and sperm) selecting for certain traits
are the short sections of DNA that are synthesized on the lagging strand of the replicating DNA
Okazaki Fragments
How can you know if the information is based on scientifically collected data and if it's corroborated by other sources? Look more closely around the web page. Click the "serious risks" link in the fourth paragraph; then click the "scientific review" link in the sixth paragraph. What do you find when you click these two links?
One links to another page on the CFS web site, and one links to a paper in a peer-reviewed journal.
Now, search for information on GMOs on at least two other web sites, including the United States Department of Agriculture (USDA.gov) and the World Health Organization (WHO.int). Is the information provided by these sites consistent with what you found on the CFS web site?
Other sites discuss both the risks and benefits associated with GMOs.
2.
PCR
Which of the following statements about DNA synthesis is true?
Primers are short sequences that allow the initiation of DNA synthesis.
Which of the following statements describes one difference between DNA replication in prokaryotes and DNA replication in eukaryotes?
Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many.
The synthesis of a new strand begins with the synthesis of a(n) _____.
RNA primer complementary to a preexisting DNA strand
In the Hershey and Chase experiment that helped confirm that DNA, not protein, was the hereditary material, what was the key finding?
Radioactively labeled phosphorus was present inside the infected bacteria. Submit
For a gene cloning experiment, a researcher inserts the lacZ gene into a bacterial plasmid. The lacZ gene encodes the enzyme ß-galactosidase, which catalyzes a synthetic molecule called X-gal to form a blue product. X-gal is included in the plating medium. The restriction enzyme used by the researcher cleaves a recognition sequence within the lacZ gene. Why did the researcher insert the lacZ gene into the plasmid?
Recombinant bacteria cannot produce the blue product.
A researcher is preparing to insert a human gene of interest into a bacterial plasmid in order to clone the human gene. She has genetically engineered the plasmid to carry a gene amp R , which confers resistance to the antibiotic ampicillin. She will include ampicillin in the plating medium when she grows the recombinant bacteria. Why has she engineered the plasmid to include an antibiotic resistance gene? Choose the best answer.
Recombinant bacteria that have taken up the plasmid can be recognized because they are able to survive in the presence of ampicillin.
Will grow in both media
Recombinant plasmid with vgp gene *Nonrecombiant plasmid *Recombinant plasmid but no vgp gene
In the late 1950s, Meselson and Stahl grew bacteria in a medium containing "heavy" (radioactive) nitrogen (15N) and then transferred them to a medium containing 14N, which is a less radioactive form of nitrogen. They then extracted DNA from the bacteria and centrifuged it to separate the DNA of different densities. Once the pattern found after one round of replication was observed, Meselson and Stahl could be confident of which of the following conclusions?
Replication is not conservative.
How can you know if the person or organization providing the information has the credentials and knowledge to speak on this topic? One clue is the type of web site it is--the domain name ".com" tells you that this site is owned by a commercial business. Now scan the article to find the name and credentials of the person who wrote it. What is the affiliation of the writer?
She is a health news writer and editor for TIME.
How can you know if the person or organization providing the information has the credentials and knowledge to speak on this topic? One clue is the type of web site it is--the domain name ".org" tells you that this site is run by a nonprofit organization. Now scan the post to find the name and credentials of the person who wrote it. What is the affiliation of the writer? What
She is on staff at the Center for Food Safety (CFS
Why is Suspect 1 considered more likely to have committed the crime than Suspect 2?
The crime scene sample contains DNA fragments from both the victim and Suspect 1.
Which of the following is NOT true about naked mole rats?
Their cells do not produce telomerase.
What is meant by the description "antiparallel" regarding the two strands of nucleic acids that make up DNA?
The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.
In E. coli, there is a mutation in a gene called dnaB that alters the helicase that normally acts at the origin of replication. Which of the following events would you expect to occur as a result of this mutation?
The DNA strands at the origin of replication will separate, but replication will not progress
Van der Waals Interactions
The bonds or interactions between stacked nucleotide units that help hold the DNA molecule together are
Covalent bonds
The bonds or interactions that hold together adjacent nucleotides in the sugar-phosphate backbone of DNA are
Hydrogen bonds
The bonds or interactions that hold together complementary bases from opposite strands of DNA are
If a cell were unable to produce histone proteins, which of the following effects would likely occur?
The cell's DNA couldn't be packed into its nucleus.
Which cells are most likely to have the gene for making telomerase switched on?
The cells in a developing embryo.
Erwin Chargaff observed that the proportions of adenine (A) and thymine (T) bases were always equal, as were the proportion of guanine (G) and cytosine (C). Chargaff's observation suggests which of the following statements?
The data suggest that A would always pair with T and G would always pair with C in a DNA molecule.
Although the forest is growing quickly around Chernobyl, and some of the wildlife is thriving, studies show that biodiversity around Chernobyl has been reduced by over 50% since the accident. Why?
The ionizing radiation affects the DNA of the wildlife, just as it affects the DNA of humans.
How can you know if the information is based on scientifically collected data and if it's corroborated by other sources? Look more closely at the links provided throughout the article. What do you find when you click the links provided in the second paragraph?
The links in the second paragraph all redirect the reader to more TIME Health articles.
DNA is a self-replicating molecule. What accounts for this important property of DNA?
The nitrogenous bases of the double helix are paired in specific combinations: A with T and G with C
Which of the following statements correctly describes one of Chargaff's rules regarding DNA?
The percentages of adenine and thymine are roughly equal, as are the percentages of guanine and cytosine in the DNA of a given species
Why is the town of Pripyat uninhabited?
The radiation levels in the town are still unsafe.
Addition of a nucleotide onto a DNA strand is an endergonic reaction. What provides the energy to drive the reaction?
The release of pyrophosphate from the incoming nucleotide, and then hydrolysis of the pyrophosphate to inorganic phosphate. Each deoxyribonucleotide enters the reaction as a triphosphate, and hydrolysis of the phosphates releases the free energy needed for the nucleotide to bind to the growing strand.
Which claim is best supported by evidence in this study?
The results reveal that the MCR element efficiently drives allelic conversion from heterozygous wild-type to homozygous mutant genotypes.
Griffith's experiments with S. pneumoniae were significant because they showed that traits could be transferred from one organism to another. What else did he find that was significant?
The transferred traits were heritable.
A group of six students has taken samples of their own cheek cells, purified the DNA, and used a restriction enzyme known to cut at zero, one, or two sites in a particular gene of interest.Analysis of the data obtained shows that two students each have two fragments, two students each have three fragments, and two students each have one only. What does this demonstrate?
The two students who have two fragments have one restriction site in this region.
Which of the following statements about Okazaki fragments in E. coli is true?
They are formed on the lagging strand of DNA.
Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight. What function is impaired in their cells?
They cannot repair thymine dimers.
Cold case detectives are investigating a homicide that took place 30 years ago. In reexamining the evidence, they find a tiny spot of blood on the victim's clothing that was likely left by the murderer. The DNA in the blood has partially degraded over time. What technique(s) would the blood lab technicians use in their examination of this tiny, degraded blood sample?
They would use PCR to amplify the DNA.
Which of the following enzymes is important for relieving the tension in a helix as it unwinds during DNA synthesis?
Topoisomerase
The unpaired nucleotides produced by the action of restriction enzymes are referred to as
sticky ends
Many enzymes are named for the substrate on which they work, either to build or disassemble molecules. Also, enzyme names often end in "-ase." For example, lactase is the enzyme that breaks down lactose. With a name like "telomerase," we can deduce that telomerase is probably:
an enzyme that regulates the assembly of DNA at the ends of chromosomes
During which step in the PCR cycle do primers form bonds with a single-stranded template?
annealing
On a scale of 0 to 6, where 6 is the most trustworthy, how would you rate this site? (Note that all responses will be marked as "correct" at this point.)
any
On a scale of 0 to 6, where 6 is the most trustworthy, how would you rate this site? (Note that all responses will be marked as "correct" at this point.)
any anwser is correct
This is a DNA fingerprint exhibiting samples from a victim, two suspects, and the crime scene. Which of these DNA fragments is common to both the victim and Suspect 1?
b
In order to insert a human gene into a plasmid, both must ___
be cut by the same restriction enzyme
In this example the marker DNA includes fragments that have 23,130, 9,416, 6,557, 4,361, 2,322, 2,027, and 564 base pairs. Approximately how many base pairs are in the DNA fragment indicated by the letter B?
between 6,557 and 4,361 base pairs
How does a bacterial cell protect its own DNA from restriction enzymes?
by adding methyl groups to adenines and cytosines
During which step in the PCR cycle are nucleotides used?
extension
True or false? The Taq enzyme is a type of DNA polymerase that allows researchers to separate the DNA strands during the annealing step of the PCR cycle without destroying the polymerase.
false
A mutation is identified in a single-celled eukaryote called a protist in which DNA primase does not assemble RNA primers on the lagging strand during DNA replication. Which of the following statements correctly describes a possible result of this mutation?
he lagging strand will not be replicated normally.
During DNA replication, which of the following enzymes separates the DNA strands during replication?
helicase
The first step in the replication of DNA is catalyzed by
helicase
In a nucleosome, the DNA is wrapped around
histones
The letter C indicates _____.
histones
Some bacteria may be able to respond to environmental stress by increasing the rate at which mutations occur during cell division. How might this be accomplished?
horizontal gene transferan increase in the amount of mistakes in DNA replicationthe movement of mobile genetic elements
Video Tutor Session Quiz: DNA Profiling
https://quizlet.com/407875880/dna-replication-and-transcription-post-lecture-flash-cards/
Ch 13 HW #2 question 14
https://rhshwhelp.wordpress.com/2017/02/17/mastering-biology-chapter-16/
Which one of the following statements is correct?
if a restriction enzyme is combined with a piece of DNA that contains its restriction site, the result will be restriction fragments.
A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to the antibiotics ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics.Bacteria that contain the plasmid, but not the eukaryotic gene, would grow in which of the following conditions?
in all four types of broth
A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to the antibiotics ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics.Bacteria containing a plasmid into which the eukaryotic gene has been inserted would grow in which of the following conditions?
in the ampicillin broth and the nutrient broth
Which of the following is an example of "recombinant DNA technology"?
introducing a human gene into a bacterial plasmid
During DNA replication, an open section of DNA, in which a DNA polymerase can replicate DNA, is called the _____.
replication fork
The action of helicase creates ___
replication forks and replication bubbles
The action of helicase creates _____.
replication forks and replication bubbles
Which type of enzyme was used to produce the DNA molecule in the figure above?
restriction enzyme
Which of the following molecule(s) help(s) to hold the DNA strands apart while they are being replicated?
single-strand DNA binding proteins
In his work with pneumonia-causing bacteria and mice, Griffith found that
some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic
Which of the following diagrams most clearly shows the overall 3D shape and atomic composition of DNA?
space filling model
In addition to the risk of accidents, which of the following is a problem when nuclear power is used as a method of generating electrical power?
storage and disposal of spent fuel rods
Which of the following diagrams most clearly shows the details of the bonds between nitrogenous bases of complementary nucleotide pairs?
structural diagram
You can tell that this is an image of a DNA nucleotide and not an RNA nucleotide because you see a _
sugar with two, and not three, oxygen atoms
What are the chemical components of a DNA molecule? Select all that apply.
sugars, nitrogenous bases, phosphate groups
What is this an image of?
supercoils
To create a molecule of recombinant DNA, which of the following is cut with a restriction enzyme?
target DNA, starting DNA
What are the repetitive DNA sequences present at the ends of eukaryotic chromosomes called?
telomeres
An old DNA strand is used as a _____ for the assembly of a new DNA strand.
template
3.
the DNA will move up the gel
A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to the antibiotics ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus ampicillin and tetracycline, and nutrient broth without antibiotics.Bacteria that do not take up any plasmids would grow on which media?
the nutrient broth only
Which of the following sources would provide you with the most reliable scientific context for the article you just read? Choose the best answer.
the original National Health and Nutrition Examination Survey with additional details about how the survey was conducted
5.
the profile from suspect 2 matches the crime scene
Which of the following characteristics of the structure of DNA allows it to carry a large amount of hereditary information?
the sequence of bases
Which of these nitrogenous bases is found in DNA but not in RNA?
thymine
In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand.
thymine...cytosine
Drag the arrows onto the diagram below to indicate the direction that DNA polymerase III moves along the parental (template) DNA strands at each of the two replication forks. Arrows can be used once, more than once, or not at all.
yass
Drag the correct labels to the appropriate locations in the diagram to show the composition of the daughter DNA molecules after one and two cycles of DNA replication. In the labels, the original parental DNA is blue and the DNA synthesized during replication is red.
yass
Drag the labels to their appropriate locations in the flowchart below, indicating the sequence of events in the production of fragment B. (Note that pol I stands for DNA polymerase I, and pol III stands for DNA polymerase III.)
yass
Drag the labels to their appropriate locations on the diagram below. Targets of Group 1 can be used more than once.
yass
DNA is a double-stranded molecule made up of complementary, antiparallel strands. Based on what you know about complementary base pairing, fill in the rest of the details in the figure. Drag the labels to their correct positions.
yass boo : the top left corner is an -oh group though!
Sort the phrases into the appropriate bins depending on which protein they describe.
yess
