Transposable Elements Move in Genome + can Create Mutations

Question 1

what are transposable elements

Answer 1

DNA sequences that can move within + between chromosomes inserting into various areas in genome (jumping genes)

Question 2

what good things might TE do to the genome

Answer 2

help modify + reshape it

Question 3

what bad things might TE movement cause

Answer 3

mutations, disrupt genes, chm damage e.g double strand breaks

Question 4

2 groups of transposable elements

Answer 4

retrotransposons

DNA transposons

Question 5

what do DNA transposons do

Answer 5

move places without going through an RNA intermediate stage

Question 6

what are located on each transposable elements end

Answer 6

inverted terminal repeats (ITRs)

Question 7

what codes for transposase enzyme

Answer 7

open reading frame

Question 8

what are both needed for movement around genome

Answer 8

inverted terminal repeats

open reading frame

Question 9

what are ITRs recognised and bound by

Answer 9

transposase enzyme

Question 10

what are made due to TE insertion process

Answer 10

direct repeats

Question 11

2 things DNA transposons are

Answer 11

autonomous

non-autonomous

Question 12

how can autonomous transposons move by themselves

Answer 12

as they encode a transposase and have intact inverted terminal repeats

Question 13

why can’t non-autonous transposons move alone

Answer 13

don’t encode their own transposase enzyme, they need autonomous transposon in genome to use theirs

Question 14

what mechanisms do most DNA transposons use when moving in genome

Answer 14

cut and paste mechanisms (transposon gene gets cut out of genome and inserted into new position in same/diff ch)

Question 15

what allows release of transposon, which stays bound by transposase

Answer 15

transposase enzyme binding to TE ends, making cuts between transposon DNA and chm DNA

Question 16

what does transposase do, before inserting transposon into new place

Answer 16

makes staggered cuts in chm DNA, leaving 5 and 3’ single-stranded DNA overhangs.

Question 17

what do retrotransposons use as an intermediate to amplify and move within genome

Answer 17

RNA

Question 18

what do retrotransposons resemble in ways, as they replicate too using similar mechanisms

Answer 18

retroviruses

Question 19

why aren’t retrotransposons infective, unlike retroviruses

Answer 19

as they don’t encode all proteins needed to form mature viruses

Question 20

which transposons are more common (39% more) in human genome

Answer 20

retrotransposons

Question 21

2 types of retrotransposons which can be autonomous/ non-autonomous

Answer 21

long terminal repeats (LTRs)

non-LTRs

Question 22

what transcribes retrotransposons DNA into 1/more RNA copies in first step of process

Answer 22

cell’s RNA polymerase

Question 23

2 enzymes needed in retrotransposon process

Answer 23

reverse trascriptase

integrase

Question 24

what does reverse transcriptase do to RNAs

Answer 24

converts them to double-stranded

Question 25

what does integrate do when it recognises double-stranded DNA ends

Answer 25

inserts retrotransposons back into genome

Question 26

what may retrotransposons do at many genome sites

Answer 26

create mutations