Question 1

Which organism exhibits retrotransposition?

Accepted Answer

A)  C. elegans 
B)  E. coli 
C)  S. aureus 
D)  E. coli and S. aureus 
E)  All of these 
A)  C. elegans 
B)  E. coli 
C)  S. aureus 
D)  E. coli and S. aureus 
E)  All of these

Question 2

What is the function of HeT-A and TART transposons in flies?

Accepted Answer

A)  Provide genetic variation by randomly hopping throughout the genome 
B)  To counterbalance the loss of chromosomal ends 
C)  To promote crossing-over between homologous chromosomes 
D)  To aid in the segregation of chromosomes 
E)  They have no known function. 
A)  Provide genetic variation by randomly hopping throughout the genome 
B)  To counterbalance the loss of chromosomal ends 
C)  To promote crossing-over between homologous chromosomes 
D)  To aid in the segregation of chromosomes 
E)  They have no known function.

Question 3

Which of the following describes the category of transposons in which transposition is accomplished through a process that involves replication of the transposable element's DNA?

Accepted Answer

A)  Cut and paste transposons 
B)  Replicative transposons 
C)  Retrotransposons 
D)  Cut and paste transposons and replicative transposons 
E)  All of these 
A)  Cut and paste transposons 
B)  Replicative transposons 
C)  Retrotransposons 
D)  Cut and paste transposons and replicative transposons 
E)  All of these

Question 4

Which of the following statements about IS elements is not correct?

Accepted Answer

A)  IS elements are responsible for the formation of Hfr strains of E. coli. 
B)  IS elements are less than 2,500 nucleotide pairs in size and contain only genes involved with promoting or regulating transcription. 
C)  IS elements are demarcated by short, inverted terminal repeats which have no role in the transpositional process. 
D)  IS elements are capable of creating target site duplications. 
E)  All of these are correct. 
A)  IS elements are responsible for the formation of Hfr strains of E. coli. 
B)  IS elements are less than 2,500 nucleotide pairs in size and contain only genes involved with promoting or regulating transcription. 
C)  IS elements are demarcated by short, inverted terminal repeats which have no role in the transpositional process. 
D)  IS elements are capable of creating target site duplications. 
E)  All of these are correct.

Question 5

If the P element of Drosophila contained no introns,would this affect the viability of P element carriers? If so,how?

Accepted Answer

Yes.P elements are restricted to hopping

Question 6

Which of the following crosses would result in the movement of P elements and subsequent hybrid dysgenesis?

Accepted Answer

A)  P cytotype females x P cytotype males 
B)  M cytotype females x M cytotype males 
C)  P cytotype females x M cytotype males 
D)  M cytotype females x P cytotype males 
E)  Hybrid dysgenesis is not induced by cytotype. 
A)  P cytotype females x P cytotype males 
B)  M cytotype females x M cytotype males 
C)  P cytotype females x M cytotype males 
D)  M cytotype females x P cytotype males 
E)  Hybrid dysgenesis is not induced by cytotype.

Question 7

L1 transposition is known to cause disease when it is inserted into the gene for

Accepted Answer

A)  Factor VII. 
B)  Huntingtin. 
C)  Dystrophin. 
D)  b-globin. 
E)  None of these 
A)  Factor VII. 
B)  Huntingtin. 
C)  Dystrophin. 
D)  b-globin. 
E)  None of these

Question 8

Retroviruses and retrovirus-like elements share all of the following genes except

Accepted Answer

A)  Gag. 
B)  Pol. 
C)  Env. 
D)  Gag and Pol. 
E)  Pol and Env. 
A)  Gag. 
B)  Pol. 
C)  Env. 
D)  Gag and Pol. 
E)  Pol and Env.

Question 9

What is the hobo element found in Drosophila?

Accepted Answer

A)  Ac/Ds element 
B)  Replicative transposon 
C)  Retrotransposon 
D)  Tn3 
E)  IS 
A)  Ac/Ds element 
B)  Replicative transposon 
C)  Retrotransposon 
D)  Tn3 
E)  IS

Question 10

Which of the following statements is true about Tn3 elements?

Accepted Answer

A)  Tn3 form a cointegrate structure mediated by the tnpA gene product. 
B)  The cointegrate structure is required for replication. 
C)  Transposition is repressed by the dual nature of the tnpA gene product. 
D)  Tn3 elements are highly mobile. 
E)  All of these 
A)  Tn3 form a cointegrate structure mediated by the tnpA gene product. 
B)  The cointegrate structure is required for replication. 
C)  Transposition is repressed by the dual nature of the tnpA gene product. 
D)  Tn3 elements are highly mobile. 
E)  All of these

Question 11

Which of the following composite transposons exhibits differences (non-identical nature)in its flanking IS elements?

Accepted Answer

A)  Tn 10 
B)  Tn 5 
C)  Tn 3 
D)  Tn 2 
E)  Tn 1 
A)  Tn 10 
B)  Tn 5 
C)  Tn 3 
D)  Tn 2 
E)  Tn 1

Question 12

When a bacterial cell is infected with a nonlytic bacteriophage with Tn5 on its chromosome,the frequency of Tn5 transposition is dramatically reduced if Tn5 is already maintained on the bacterial chromosome.Why?

Accepted Answer

A)  Phage integration occurs via Tn5 homology disrupting the transposase. 
B)  Tn5 transposition is inhibited by phage gene products. 
C)  Tn5 on the bacterial chromosome expresses a repressor of transposition. 
D)  Transposase is not expressed from Tn5 elements integrated within the bacterial chromosome. 
E)  None of these 
A)  Phage integration occurs via Tn5 homology disrupting the transposase. 
B)  Tn5 transposition is inhibited by phage gene products. 
C)  Tn5 on the bacterial chromosome expresses a repressor of transposition. 
D)  Transposase is not expressed from Tn5 elements integrated within the bacterial chromosome. 
E)  None of these

Question 13

When IS elements insert into chromosomes or plasmids,they create a duplication of part of the DNA sequence at the site of the insertion,with one copy of the duplication on each side of the element known as

Accepted Answer

A)  inverted terminal repeats. 
B)  target site duplications. 
C)  target site deletions. 
D)  inverted terminal duplications. 
E)  inverted terminal deletions. 
A)  inverted terminal repeats. 
B)  target site duplications. 
C)  target site deletions. 
D)  inverted terminal duplications. 
E)  inverted terminal deletions.

Question 14

Which of the following is true regarding cut and paste transposons in eukaryotes?

Accepted Answer

A)  These elements have inverted repeats at their termini. 
B)  These elements create target site duplications when they insert into DNA molecules. 
C)  Some encode a transposase that catalyzes the movement of the element from one position to another. 
D)  All of these 
E)  None of these 
A)  These elements have inverted repeats at their termini. 
B)  These elements create target site duplications when they insert into DNA molecules. 
C)  Some encode a transposase that catalyzes the movement of the element from one position to another. 
D)  All of these 
E)  None of these

Question 15

Which of the following is true regarding the Ac element in maize?
1)Ac elements consist of 4563 nucleotide pairs.
2)Ac elements are bounded by inverted repeats that are 11 nucleotide pairs long.
3)Each Ac element is flanked by direct repeats 8 nucleotide pairs long.

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  1 and 2 
E)  All of these 
A)  1 
B)  2 
C)  3 
D)  1 and 2 
E)  All of these

Question 16

Which of the following is not involved in HIV infection?

Accepted Answer

A)  Docks with target cell by binding the CD4 receptor via its gp120 protein 
B)  Polymerizes 1st DNA strand synthesis by the pol gene product 
C)  First strand synthesis is primed by snRNA. 
D)  DNA:RNA hybrid is degraded by RNase H. 
E)  The tRNA primer is prepackaged in the viral particle along with reverse transcriptase. 
A)  Docks with target cell by binding the CD4 receptor via its gp120 protein 
B)  Polymerizes 1st DNA strand synthesis by the pol gene product 
C)  First strand synthesis is primed by snRNA. 
D)  DNA:RNA hybrid is degraded by RNase H. 
E)  The tRNA primer is prepackaged in the viral particle along with reverse transcriptase.

Question 17

Why do Drosophila,from a P male x M female cross,generate viable offspring?

Accepted Answer

A)  P element transposase is repressed in germ cells, at the level of RNA splicing. 
B)  P element transposase is repressed in germ cells, at the level of transcription. 
C)  P element transposase is repressed in somatic cells, at the level of RNA splicing. 
D)  P element transposase is repressed in somatic cells, at the level of transcription. 
E)  P male x M female crosses do not generate viable offspring. 
A)  P element transposase is repressed in germ cells, at the level of RNA splicing. 
B)  P element transposase is repressed in germ cells, at the level of transcription. 
C)  P element transposase is repressed in somatic cells, at the level of RNA splicing. 
D)  P element transposase is repressed in somatic cells, at the level of transcription. 
E)  P male x M female crosses do not generate viable offspring.

Question 18

Which type of transposon is a composite transposon?

Accepted Answer

A)  Cut and paste transposon 
B)  Replicative transposon 
C)  Retrotransposon 
D)  Retrovirus-like transposon 
E)  All of these 
A)  Cut and paste transposon 
B)  Replicative transposon 
C)  Retrotransposon 
D)  Retrovirus-like transposon 
E)  All of these

Question 19

Which of the following has accelerated the spread of multiple drug resistance among bacterial infections?

Accepted Answer

A)  Conjugative R plasmids 
B)  F plasmids 
C)  Col plasmids 
D)  Tn3 elements 
E)  All of these 
A)  Conjugative R plasmids 
B)  F plasmids 
C)  Col plasmids 
D)  Tn3 elements 
E)  All of these

Question 20

Some mariner elements show a high degree of similarity between organisms that are separated by millions of years of evolutionary time.What is the current explanation for this?

Accepted Answer

A)  Mariner is highly conserved. 
B)  Mariner was horizontally transferred by bacterium. 
C)  Mariner was horizontally transferred by virus. 
D)  Mariner elements in divergent species have arisen through inter-species breeding events. 
E)  None of these 
A)  Mariner is highly conserved. 
B)  Mariner was horizontally transferred by bacterium. 
C)  Mariner was horizontally transferred by virus. 
D)  Mariner elements in divergent species have arisen through inter-species breeding events. 
E)  None of these

Exam 17: Transposable Genetics Elements

Which organism exhibits retrotransposition?

What is the function of HeT-A and TART transposons in flies?

Which of the following describes the category of transposons in which transposition is accomplished through a process that involves replication of the transposable element's DNA?

Which of the following statements about IS elements is not correct?

If the P element of Drosophila contained no introns,would this affect the viability of P element carriers? If so,how?

Which of the following crosses would result in the movement of P elements and subsequent hybrid dysgenesis?

L1 transposition is known to cause disease when it is inserted into the gene for

Retroviruses and retrovirus-like elements share all of the following genes except

What is the hobo element found in Drosophila?

Which of the following statements is true about Tn3 elements?

Which of the following composite transposons exhibits differences (non-identical nature)in its flanking IS elements?

When a bacterial cell is infected with a nonlytic bacteriophage with Tn5 on its chromosome,the frequency of Tn5 transposition is dramatically reduced if Tn5 is already maintained on the bacterial chromosome.Why?

When IS elements insert into chromosomes or plasmids,they create a duplication of part of the DNA sequence at the site of the insertion,with one copy of the duplication on each side of the element known as

Which of the following is true regarding cut and paste transposons in eukaryotes?

Which of the following is true regarding the Ac element in maize? 1)Ac elements consist of 4563 nucleotide pairs. 2)Ac elements are bounded by inverted repeats that are 11 nucleotide pairs long. 3)Each Ac element is flanked by direct repeats 8 nucleotide pairs long.

Which of the following is not involved in HIV infection?

Why do Drosophila,from a P male x M female cross,generate viable offspring?

Which type of transposon is a composite transposon?

Which of the following has accelerated the spread of multiple drug resistance among bacterial infections?

Some mariner elements show a high degree of similarity between organisms that are separated by millions of years of evolutionary time.What is the current explanation for this?

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