BCH 369 OWL 10/23

Jul 11th, 2023
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11 test answers
question
Which of the main pathways for protein degradation makes use of a subcellular organelle?A)LysosomesB)Proteasomes
answer
A. lysosomes
question
Which of the following parameters affects the distance DNA molecules migrate during electrophoresis, at pH = 8?A)The mass of the DNAB)The total ionic charge on the DNA moleculeC)The fact that each nucleotide contributes one negative charge at this pHD)The concentration of agarose or polyacrylamide in the gelE)All of these features control the distance the DNA migrates
answer
Elarger the pore size, larger the mass
question
Fluorescence and other luminescent methods of visualizing bands offer these advantages over methods dependent on radioactivity.A)They can detect smaller amounts of material (they are more sensitive).B)Fluorescent molecules like ethidium bromide don't have as great a health hazard as radioisotopes do.C)Special licenses are required to work with radioisotopes.D)These methods are both more sensitive and require no special license.E)All of these are advantages.
answer
E
question
Which of the following statements concerning restriction endonucleases is true?A)They attack RNA, not DNA.B)They attack single-stranded sequences only.C)They can produce sticky ends.D)They do not display sequence specificity in their site of attack.
answer
The presence of bacterial or viral clones is detected experimentally byA)the presence of colonies or plaques on a suitably prepared Petri dish.B)gel electrophoresis.C)analytical ultracentrifugation.D)x-ray crystallography.
question
Which of the following statements concerning restriction endonucleases is true?A)They attack RNA, not DNA.B)They attack single-stranded sequences only.C)They can produce sticky ends.D)They do not display sequence specificity in their site of attack.
answer
CRestriction endonucleases are specific for dsDNA - they will not bind either dsRNA or ssDNA. Their primary utility lies in the fact that they are VERY specific and therefore predictable and dependable. Some produce blunt ends but the ones most useful in cloning are those that produce sticky ends. This allows to separate molecules of DNA with similar sticky ends to base pair for association and easier ligation.
question
The presence of bacterial or viral clones is detected experimentally byA)the presence of colonies or plaques on a suitably prepared Petri dish.B)gel electrophoresis.C)analytical ultracentrifugation.D)x-ray crystallography.
answer
AHere it is important to recognize the goal - to pick a colony or plaque of living cells that carry the plasmid. Each colony will represent multiple copies of the same clone so that they are genetically identical. Once we have the clone - we can grow up the cells and perform some of these other studies.
question
This is a map of the pBR322 plasmid; numbers on the map refer to the base where the site is located.(DIAGRAM)If a recombinant plasmid were obtained inserting DNA into the AflIII site, the recombinant plasmid would lack which of the following properties?A)It will be resistant to the antibiotic tetracycline.B)It will be resistant to the antibiotic ampicillin.C)It will possess at lest two promoter sites.D)It can replicate autonomously.E)All of these are true for the recombined plasmid.
answer
DNotice that if insert a segment of DNA into the Afl III site it will disrupt the Ori site or origin of replication. This will mean the lack of a site to which DNA polymerase can bind to replicate the plasmid. Even if transformation into a host is successful, expression will not occur.
question
In three separate tubes, the plasmid given below is treated with one of these restriction endonucleases: EcoRI, BamHI, and HindIII. Which of the following best represents the electrophoretic gel one would see from these digests?(DIAGRAM)
answer
A2 cuts = 2 bands, 1 cut = 1 band, etc
question
How does an expression vector differ from a regular cloning vector?A)An expression vector does not have an origin of replication.B)An expression vector is always a linear molecule, while a cloning vector may be circular.C)An expression vector has the ability to have the inserted DNA be transcribed.D)An expression vector must be of viral origin, so that it can infect a cell naturally.
answer
C*product*A cloning vector is used to insert and amplify foreign DNA - not necessarily its expressed product. In the case of an expression vector, we want to clone the gene so that it can be expressed in the host.
question
The best primers for the PCR reaction have the following feature:A)They have a high G?C content.B)They have a high A?T content.C)They should be palindromic.D)The AT/GC ratio does not matter.E)They should anneal rapidly, before the larger DNA strands reanneal.
answer
E*want short templates*This is key to ensuring that the entire process works. Design of PCR primers involves consideration of both size and content.
question
Each band in a lane of a Sanger-Coulson sequencing gel representsA)random cutting of DNAB)a single nucleotide that ran that far on a gelC)a piece of DNA that ended in a specific baseD)none of these
answer
C
1 of 11
question
Which of the main pathways for protein degradation makes use of a subcellular organelle?A)LysosomesB)Proteasomes
answer
A. lysosomes
question
Which of the following parameters affects the distance DNA molecules migrate during electrophoresis, at pH = 8?A)The mass of the DNAB)The total ionic charge on the DNA moleculeC)The fact that each nucleotide contributes one negative charge at this pHD)The concentration of agarose or polyacrylamide in the gelE)All of these features control the distance the DNA migrates
answer
Elarger the pore size, larger the mass
question
Fluorescence and other luminescent methods of visualizing bands offer these advantages over methods dependent on radioactivity.A)They can detect smaller amounts of material (they are more sensitive).B)Fluorescent molecules like ethidium bromide don't have as great a health hazard as radioisotopes do.C)Special licenses are required to work with radioisotopes.D)These methods are both more sensitive and require no special license.E)All of these are advantages.
answer
E
question
Which of the following statements concerning restriction endonucleases is true?A)They attack RNA, not DNA.B)They attack single-stranded sequences only.C)They can produce sticky ends.D)They do not display sequence specificity in their site of attack.
answer
The presence of bacterial or viral clones is detected experimentally byA)the presence of colonies or plaques on a suitably prepared Petri dish.B)gel electrophoresis.C)analytical ultracentrifugation.D)x-ray crystallography.
question
Which of the following statements concerning restriction endonucleases is true?A)They attack RNA, not DNA.B)They attack single-stranded sequences only.C)They can produce sticky ends.D)They do not display sequence specificity in their site of attack.
answer
CRestriction endonucleases are specific for dsDNA - they will not bind either dsRNA or ssDNA. Their primary utility lies in the fact that they are VERY specific and therefore predictable and dependable. Some produce blunt ends but the ones most useful in cloning are those that produce sticky ends. This allows to separate molecules of DNA with similar sticky ends to base pair for association and easier ligation.
question
The presence of bacterial or viral clones is detected experimentally byA)the presence of colonies or plaques on a suitably prepared Petri dish.B)gel electrophoresis.C)analytical ultracentrifugation.D)x-ray crystallography.
answer
AHere it is important to recognize the goal - to pick a colony or plaque of living cells that carry the plasmid. Each colony will represent multiple copies of the same clone so that they are genetically identical. Once we have the clone - we can grow up the cells and perform some of these other studies.
question
This is a map of the pBR322 plasmid; numbers on the map refer to the base where the site is located.(DIAGRAM)If a recombinant plasmid were obtained inserting DNA into the AflIII site, the recombinant plasmid would lack which of the following properties?A)It will be resistant to the antibiotic tetracycline.B)It will be resistant to the antibiotic ampicillin.C)It will possess at lest two promoter sites.D)It can replicate autonomously.E)All of these are true for the recombined plasmid.
answer
DNotice that if insert a segment of DNA into the Afl III site it will disrupt the Ori site or origin of replication. This will mean the lack of a site to which DNA polymerase can bind to replicate the plasmid. Even if transformation into a host is successful, expression will not occur.
question
In three separate tubes, the plasmid given below is treated with one of these restriction endonucleases: EcoRI, BamHI, and HindIII. Which of the following best represents the electrophoretic gel one would see from these digests?(DIAGRAM)
answer
A2 cuts = 2 bands, 1 cut = 1 band, etc
question
How does an expression vector differ from a regular cloning vector?A)An expression vector does not have an origin of replication.B)An expression vector is always a linear molecule, while a cloning vector may be circular.C)An expression vector has the ability to have the inserted DNA be transcribed.D)An expression vector must be of viral origin, so that it can infect a cell naturally.
answer
C*product*A cloning vector is used to insert and amplify foreign DNA - not necessarily its expressed product. In the case of an expression vector, we want to clone the gene so that it can be expressed in the host.
question
The best primers for the PCR reaction have the following feature:A)They have a high G?C content.B)They have a high A?T content.C)They should be palindromic.D)The AT/GC ratio does not matter.E)They should anneal rapidly, before the larger DNA strands reanneal.
answer
E*want short templates*This is key to ensuring that the entire process works. Design of PCR primers involves consideration of both size and content.
question
Each band in a lane of a Sanger-Coulson sequencing gel representsA)random cutting of DNAB)a single nucleotide that ran that far on a gelC)a piece of DNA that ended in a specific baseD)none of these
answer
C