21.4 Genetic engineering

Question 1

what is genetic engineering?

Answer 1

the manipulation of the genome

Question 2

basic outline of genetic engineering

Answer 2

desirable gene is isolated and then placed in another organism using a suitanle vector

Question 3

what is an organism which carries a gene from another organism called?

Answer 3

transgenic
a genetically modified organism

Question 4

what enzymes are used for isolating the desired gene?

Answer 4

restriction endonucleases

Question 5

what is a sticky end?

Answer 5

a few bases left behind when the restriction endonucleases cuts the desired gene out

Question 6

why are sticky ends useful?

Answer 6

makes it easier to insert a desired gene into the DNA of another organism

Question 7

what are the two techniques for isolating a gene?

Answer 7

use of restriction endonucleases
use of reverse transcriptase

Question 8

how is reverse transcriptase used to remove a desired gene?

Answer 8

used to produce a single strand of complimentary DNA from mRNA

Question 9

why is the use of reverse transcriptase an advantage?

Answer 9

it makes it easier to identify the desired gene as the mRNA produced will be very different to the desired gene isolated by reverse transcriptase

Question 10

what is the isolated DNA inserted into to be able to reach a host cell?

Answer 10

a vector

Question 11

what is the most common vector used in genetic engineering?

Answer 11

bacterial plasmids

Question 12

why are bacterial plasmids the preffered vector?

Answer 12

they are small
they can replicate independently

Question 13

what is recombiant DNA?

Answer 13

when the plasmid goes into a new host cell and combines with the host’s DNA

Question 14

what do plasmids used for vectors contain?

Answer 14

marker genes

Question 15

what is an example of a marker gene?

Answer 15

one which gives antibiotic resistance
the bacteria is grown in a media containing antibiotic
checks that the bacteria has taken up the plasmid

Question 16

what is used to cut open the plasmid?

Answer 16

the same restriction endonuclease used to isolate the desired gene

Question 17

why is it important that the plasmid is cut using the same restriction endonuclease?

Answer 17

it ensures that the sticky ends formed in the plasmid are complimentary to the bases in the desired gene

Question 18

how is the desired gene connected to the rest of the DNA in a plasmid?

Answer 18

DNA ligase forms phosphodiester bonds between the sugar and phosphate groups which joins the strands together

Question 19

what is the second gene marker in a plasmid used for?

Answer 19

to show whether a plasmid contains the recombinant gene

Question 20

how does the second gene marker activated?

Answer 20

if the DNA marker is inserted then the marker gene does not function

Question 21

what is transformation?

Answer 21

the process of transferring the plasmid containing the recombinant DNA into the host cell

Question 22

what are the methods of transformation?

Answer 22

• permeable membranes
• electroporation

Question 23

how are permeable membranes used for transformation?

Answer 23

the plasmid is placed in a calcium rich medium and high temperature in which the bacterial membrane to become more permeable to allow plasmids to enter

Question 24

what is electroporation?

Answer 24

when a small electric current is applied to the bacteria and the membrane becomes more porous to allow the plasmid to enter the cell

Question 25

why is electroporation less useful in whole organisms?

Answer 25

the electric current can cause the membrane to become damaged and destroys the cell

Question 26

what is electrofusion?

Answer 26

when a tiny electric is applied to the membranes of two cells which causes the cells to fuse and form a hybrid cell

Question 27

what does the hybrid cell formed from electrofusion contain?

Answer 27

the DNA from both fused cells

Question 28

why is electrofusion difficult in animal cells?

Answer 28

they are more difficult to fuse

Question 29

how is electrofusion used to produce monoclonal antibodies?

Answer 29

when a tumour cell is fused with an antibody

forms a hybridoma

allows it to rapidly divide

Question 30

what is a transformed cell?

Answer 30

a cell which has taken up a vector containing the desired gene

Question 31

what are prokaryotes used in genetic engineering for?

Answer 31

bacteria have been genetically modified to produce:
- insulin
- clotting factors
- antibiotics
- vaccines

Question 32

how are plants genetically modified?

Answer 32

a desired gene is placed in a plasmid with a marker gene

then carried to the plant cell DNA

callus forms which can each grow into a new plant

Question 33

diagram for genetic engineering in plasmid

Answer 33

Question 34

diagram for genetic engineering with a plant

Answer 34