genetic engineering

Question 1

define genetic engineering

Answer 1

modifying the characteristics of an organism by manipulating its genetic material

Question 2

define transgenic

Answer 2

organism that carries a gene from another organism

Question 3

define vector

Answer 3

a DNA molecule (often plasmid or virus) that is used to carry a particular DNA segment into a host cell

Question 4

define recombinant DNA

Answer 4

DNA that has genetic material from two or more different organisms

Question 5

define transformation

Answer 5

genetic alteration of a cell resulting from the direct uptake + incorporation of genetic material from its surroundings through the cell membrane(s)

Question 6

define electroporation

Answer 6

use of small electric current to transfer genetically engineered plasmids into bacteria/to get DNA fragments directly into eukaryotic cells

Question 7

define marker gene

Answer 7

a gene used to determine if a nucleic acid sequence has been successfully inserted into an organism’s DNA

Question 8

define DNA ligase

Answer 8

enzyme that facilitates joining of DNA strands together by catalysing the formation of a phosphodiester bond

Question 9

define sticky ends

Answer 9

staggered regions of DNA with unpaired, exposed bases

Question 10

describe the priniciple of genetic engineering

Answer 10

isolating a gene for a desirable characteristic in one organism and placing it into another organism using a suitable vector

Question 11

describe the 2 ways a desired gene can be isolated

Answer 11

• restriction endonucleases cut gene to form sticky ends
• reverse transcriptase - converts mRNA to cDNA

Question 12

explain how marker genes can be used to identify organisms that have been successfully genetically engineered.

Answer 12

• plasmids are genetically engineered to contain marker gene (eg antibiotic resistance)
• gene of interest is spliced into middle of marker gene = ceases MG function
• if gene is inserted successfully, bacteria will not show characteristic for MG

Question 13

list 3 ways in which a recombinant plasmid can be inserted into target cells.

Answer 13

• electroporation
• heat shock (in calcium rich solution)
• electrofusion

Question 14

describe electrofusion

Answer 14

tiny currents applied to membranes of two different cells, fusing the cells and nuclear membranes to form a hybrid/polyploid cell containing DNA from both