Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Molecular Biology > Ch. 15 Transposable Elements & Retroviruses (Exam 2) > Flashcards

Ch. 15 Transposable Elements & Retroviruses (Exam 2) Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What are transposons?

A

Mobile elements capable of transporting themselves to other locations in the genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are Class II (DNA-type) elements?

A

Transposons able to manipulate DNA to spread themselves throughout the genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are Class I (retroelement) elements?

A

Transposons able to move only bc of their ability to make DNA out of their RNA and integrate that DNA into new sites in the genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

You’ll find transposons that use DNA to mobilize in both prokaryotes and eukaryotes, but transposons that use an RNA intermediate are predominantly found in…

A

Eukaryotes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How do transposable elements cause variation in the genome?

A

They promote genome rearrangement either directly or indirectly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Transposons serve as substrates for cellular recombination systems by functioning as…

A

Portable regions of homology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why is it bad to have two copies of a transposon at different locations?

A

Deletions, insertions, inversions, or translocations can occur, which would be abnormal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In 1950, Barbara McClintock discovered the first transposable elements in corn. What were they?

A

Ac/Ds elements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are insertion sequence (IS) elements?

A

The simplest bacterial transposons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are composite elements?

A

IS elements bordering/flanking a DNA segment with one or more genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How are Tn3-type transposons unique?

A

They have their own transposase and do not require IS elements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are transposable phages?

A

Bacterial viruses which transpose as part of their normal infection cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is transposase?

A

Enzyme that catalyzes transposition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is special about the IS elements in composite transposons?

A

They have inverted terminal repeats and generate direct repeats of flanking DNA at the target site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a common mechanism that transposons use to introduce themselves in DNA?

A

Nicks are placed contralaterally (up-left, down-right) at the target site of a DNA strand, and the transposon is placed between the target site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is replicative transposition?

A

Transposon copied as part of its movement such that a copy is made each time it enters a new site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

While transposase works on the ends of the original transposon, resolvase words on the…

A

Duplicated copies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is nonreplicative transposition?

A

Transposon moves from one site to another without being copied

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The mechanism behind nonreplicative transposition is often referred to as…

A

Cut-and-paste

20
Q

What effect does nonreplicative transposition have on the donor strand?

A

The donor strand now has a DSB that must be repaired

21
Q

What is cointegration?

A

Fusion of donor and recipient replicon that creates two copies of a transposon, which results in homologous recombination of the copies into 2 different replicons

22
Q

Mu transposition is a mechanism of cointegration, so, therefore, it is a type of { } transposition.

A

Replicative

23
Q

What is breakage & reunion?

A

Mechanism of nonreplicative transposition in which donor remains broken w/ DSB

24
Q

How exactly does nonreplicative transposition result from crossing over?

A

The crossover structure itself is released by nicking, so a DSB is left behind

25
Q

What does homologous recombination of multiple transposon copies lead to?

A

Rearrangement of host DNA

26
Q

The reciprocal recombination between the direct repeats causes material to be excised from between the repeats. This mechanism is very similar to… (HINT: site-specific)

A

Site-specific mitotic homologous recombination via the Cre/lox system

27
Q

What are the 3 steps of transposition in a retrovirus?

A

1) Reverse transcription
2) Integration
3) Transcription

28
Q

What enzyme is responsible for reverse transcription?

A

Reverse transcriptase

29
Q

What enzyme is responsible for integration?

A

Integrase

30
Q

How are retroviral integrases related?

A

By sequence, structure, and function to the transposase encoded by transposons

31
Q

What are R segments?

A

Short sequences repeats located at each end of viral RNA

32
Q

What is the purpose of the retroviral gag gene?

A

Code for protein components of nucleoprotein core of virion

33
Q

What is the purpose of the retroviral pol gene (HINT: pol as in polymerase)?

A

Nucleic acid synthesis and recombination

34
Q

What is the purpose of the retroviral env gene?

A

Forming viral envelope

35
Q

What are retroviruses called plus-strand viruses?

A

Viral RNA itself codes for protein products

36
Q

What is the native primer for retroviral reverse transcription?

A

tRNA

37
Q

What is the first step of reverse transcription creating DNA?

A

First, tRNA primer anneals to binding site of RNA

38
Q

Reverse transcription requires that reverse transcriptase synthesize…

A

DNA strand complementary to the RNA template

39
Q

After reverse transcriptase synthesizes a DNA strand complementary to the RNA template, the RTase then dissociates…

A

From the RNA template

40
Q

After dissociating from the RNA template, RTase associates…

A

With another template strand to continue synthesis and form a DNA strand

41
Q

How much of the genome do retroelements make up?

A

About half of it

42
Q

What are the 3 classes of retroelements?

A

1) Retrotransposons
2) Retroposons
3) Nonautonomous short-interspersed nuclear elements (SINEs)

43
Q

What is the difference between retrotransposons & retroposons?

A

Retrotransposons have LTRs while retroposons do not

44
Q

What is the purpose of long-term repeats (LTRs)?

A

Regulate gene expression via a straight-forward reverse transcription reaction

45
Q

What are short-interspersed nuclear elements (SINEs)?

A

Elements generated via an RNA-mediated transposition event that do not code for proteins but do have transposition functions

46
Q

What are long-interspersed nuclear elements (LINEs)?

A

Elements that generate genomic insertions via RNA-mediated retrotransposition

Molecular Biology (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions