cloning and genetic model systems

Question 1

RNAi (RNA interference)

Answer 1

the regulatory mechanism which a ds RNA molecule triggers the specific degradation of the corresponding messenger RNA thereby leading to silencing or knock-down of gene function

Question 2

when a ds RNA is injected _____ enzymes cuts it into the small pieces siRNA (______) these associate with..

Answer 2

dicer, small interferingR RNA, associate with RISC complex enzymes

Question 3

RISC-siRNA complex binds to mRNA that matches the siRNA sequence and

Answer 3

mRNA is cut up

Question 4

why does the RNAi mechanism exist

Answer 4

1) could have been a defense mech. for RNA viruses
2) combat the spread of transposable elements within the geneome
3) related to the regulatory system in which genes encoding small RNA called microRNA act as regulators of other genes

Question 5

cell differentiation

Answer 5

formation of different specialized cell types from an original unspecialized cell

Question 6

what experiment showed the the gene elimination hypothesis was wrong

Answer 6

frog eggs grown to adults from epithelial cells

Question 7

cloning

Answer 7

generation of genetically identical individuals using the same somatic cell nuclei transplanted into anucleate

Question 8

why is cloning difficult in mammals

Answer 8

during mammalian cell differentiation there is sometimes a modification of the chromatin that silences certain gene regions (epigenetic silencing)

Question 9

properties of a good model organism

Answer 9

short generation time, easy and cheap to grow in the lab, must be able to manipulate easily

Question 10

S. cerevisiae (baker yeast)

Answer 10

adv easily manipulated, can grow as haploid, small geneome

dis unicellular, doest relate closely to humans

Question 11

C.elegans (soil nemetode)

Answer 11

adv easily manipulated, small genome, adult is transparent

dis small size makes it difficult to identify muntant morphology not closley related to humans

Question 12

D. melanogaster (fruit fly)

Answer 12

adv easily manipulated, small genome, well studied has complex delopemnt
dis small size, not closley related to humans

Question 13

D.rerio (zebra fish)

Answer 13

easily manipulated, small genome, closley related to human

dis not super easy to grow and manipulate, relativly new model system so not much is known

Question 14

M.musculus (mouse)

Answer 14

adv easily manipulated, genome completly sequenced, very relatable to humans
dis expesive, life cycle is longer than other model orgamism

Question 15

A. thalinana (mustard weed)

Answer 15

easily manipulated, small genome, short life cylce for a plant, best plant model for genetic studies
dis its a plant not relatable to humans

Question 16

Ultimatly you want to isolate the ____ to study…

Answer 16

gene, where/when it transcribed, what protein does it encode, how does the protein product function

Question 17

why does the human genome have so much dna

Answer 17

introns, large regions of regulatory sequences, large amount of repetitive sequences