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Molecular Biology

Robert F. Weaver

Chapter 23

Transposition - all with Video Answers

Educators

Chapter Questions

02:42

Problem 1

Describe and give the results of an experiment that shows that bacterial transposons contain inverted terminal repeats.

Courtney Burson
Courtney Burson
Numerade Educator
02:00

Problem 1

A certain transposon's transposase creates staggered cuts in the host DNA five base pairs apart. What consequence does this have for the host DNA surrounding the inserted transposon? Draw a diagram to explain how the staggered cuts affect the host DNA.

Courtney Burson
Courtney Burson
Numerade Educator
01:18

Problem 2

Compare and contrast the genetic maps of the bacterial transposons IS1 and $\operatorname{Tn} 3$, and the eukaryotic transposon $A c$.

Courtney Burson
Courtney Burson
Numerade Educator
00:23

Problem 2

You are interested in measuring the rate of transfer of a hypothetical transposon, Stealth, from one plasmid, carrying two antibiotic resistance genes of its own, to another plasmid, which carries the gene for chloramphenicol resistance. (Stealth carries an ampicillin resistance gene.) Describe an experiment you would perform to assay for this transposition.

Sam Limsuwannarot
Sam Limsuwannarot
Numerade Educator
09:47

Problem 3

Diagram the mechanism of $\operatorname{Tn} 3$ transposition, first in simplified form, then in detail.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
00:58

Problem 3

Identify the end product of abortive transposition carried out by $\operatorname{Tn} 3$ transposons with mutations in the following genes.
a. Transposase
b. Resolvase

Courtney Burson
Courtney Burson
Numerade Educator
02:13

Problem 4

Diagram a mechanism for nonreplicative transposition.

Courtney Burson
Courtney Burson
Numerade Educator
00:58

Problem 4

Transposon $\mathrm{Tn} \mathrm{T}$ in plasmid A transposes to plasmid B. How many copies of $\mathrm{TnT}$ are in the cointegrate? Where are they with respect to the two plasmids in the cointegrate?

Courtney Burson
Courtney Burson
Numerade Educator
08:19

Problem 5

Explain how transposition can give rise to speckled maize kernels.

Sana Riaz
Sana Riaz
Numerade Educator
01:18

Problem 5

If the transposable element Ds of maize transposed by the same mechanism as $\mathrm{Tn} 3$, would we see the speckled kernels with the same high frequency? Why, or why not?

Courtney Burson
Courtney Burson
Numerade Educator
02:19

Problem 6

Draw a sketch of an antibody protein, showing the light and heavy chains.

Qudsiya Anis
Qudsiya Anis
Numerade Educator
01:28

Problem 6

Assume you have two cell-free transposition systems that have all the enzymes necessary for transposition of $\mathrm{Tn} 3$ and Ty, respectively. What effect would the following inhibitors have on these two systems, and why?
a. Inhibitors of double-stranded DNA replication
b. Inhibitors of transcription
c. Inhibitors of reverse transcription
d. Inhibitors of translation

Christina Sorrentino
Christina Sorrentino
Numerade Educator
05:18

Problem 7

Explain how thousands of immunoglobulin genes can give rise to many millions of antibody proteins.

Jennifer Stoner
Jennifer Stoner
Numerade Educator
03:29

Problem 7

You have identified a new transposon you call Rover. You want to determine whether Rover transposes by a retrotransposon mechanism or by a standard replication transposition mechanism such as that used by $\operatorname{Tn} 3$. Describe an experiment you would use to answer this question, and tell what the results would be in each case.

Sana Riaz
Sana Riaz
Numerade Educator
02:25

Problem 8

You are a molecular biologist interested in learning more about the fascinating process of V(D)J recombination. Assuming that you are capable of generating all of the following possible variants, explain what effect (from a molecular process standpoint as well as a physiological and/or immunological standpoint) you would expect to observe if the following were created in your laboratory:
a. the removal of all of the D gene segments from the section of the genome encoding the heavy chain of antibodies.
b. the removal of all of the D gene segments from the section of the genome encoding the beta chain of T-cell receptors.
c. the genetic alteration of the RSS flanking the D gene segments from a 12 signal to a 23 signal.
d. the elimination of expression of the RAG gene products.

Rikhil Makwana
Rikhil Makwana
Numerade Educator

Problem 8

Diagram the rearrangement of immunoglobulin lightand heavy-chain genes that occurs during B-lymphocyte maturation.

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02:56

Problem 9

Explain how the signals for V(D)J joining ensure that one and only one of each of the parts of an immunoglobulin gene will be included in the mature, rearranged gene.

Danielle Ashley
Danielle Ashley
Numerade Educator
01:26

Problem 10

Diagram a reporter plasmid designed to test the importance of the heptamer, nonamer, and spacer in a recombination signal sequence. Explain how this plasmid detects recombination.

James Kiss
James Kiss
Numerade Educator
10:58

Problem 11

Present a model for cleavage and rejoining of DNA strands at immunoglobulin gene recombination signal sequences. How does this mechanism contribute to antibody diversity?

Charles Kirschbaum
Charles Kirschbaum
Numerade Educator

Problem 12

Describe and give the results of an experiment that shows that cleavage at an immunoglobulin recombination signal sequence leads to formation of a hairpin in vitro.

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00:31

Problem 13

Present evidence for a reverse transcriptase activity in retrovirus particles and the effects of RNase on this activity.

Carlene Jimenez
Carlene Jimenez
Numerade Educator

Problem 14

Describe and show the results of an experiment that demonstrates that strong-stop reverse transcripts in retroviruses are base-paired to the RNA genome and covalently attached to an RNA primer.

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01:35

Problem 15

Illustrate the difference between the structures of the LTRs in genomic retroviral RNAs and retroviral proviruses.

Anna Miller
Anna Miller
Numerade Educator
06:47

Problem 16

Diagram the conversion of a retrovirus RNA to a provirus. Show how this explains the difference in the previous question.

Leah Lampen
Leah Lampen
Numerade Educator
01:41

Problem 17

Compare and contrast the mechanisms of retrovirus replication and retrotransposon transposition.

Rabeya Zahid
Rabeya Zahid
Numerade Educator
01:41

Problem 18

Summarize the evidence that retrotransposons transpose via an RNA intermediate.

Rabeya Zahid
Rabeya Zahid
Numerade Educator
01:11

Problem 19

Describe and show the results of an experiment that demonstrates that the endonuclease of a L.INE-like element can specifically nick one strand of the element's target DNA.

Sana Riaz
Sana Riaz
Numerade Educator

Problem 20

Describe and show the results of an experiment that demonstrates that a LINE-like element can use a nicked strand of its target DNA as a primer for reverse transcription of the element.

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06:14

Problem 21

Present a model for retrotransposition of a LINE-like element.

Sana Riaz
Sana Riaz
Numerade Educator