Genetic engineering + Gene therapy- Module 6

Question 1

Genetic engineering-

Answer 1

Genetic engineering- manipulation of an organism’s DNA to make a transformed organism.

Question 2

Recombinant DNA

Answer 2

DNA formed by joining DNA from more than one source.

Question 3

Transgenic organism.

Answer 3

An organism that has been genetically engineered to include DNA from another organism.

Question 4

Part one of Genetic engineering obtaining DNA containing the desired gene

Answer 4

Need a DNA fragment that contains the desired gene  isolated using restriction enzymes.

*Can isolate mRNA for desired gene and use enzyme reverse transcriptase to produce a strand of complementary DNA  easier to identify desired gene. E.g beta cells in pancreas make insulin so make lots of insulin mRNA molecules.

Question 5

Part 2 of Genetic engineering-Making recombinant DNA

( 4 steps)

Answer 5

1) Vector DNA is isolated

2)-vector DNA cut open using the same restriction enzyme used to isolate DNA fragment containing desired gene
-This means that the sticky ends of the ends of the vector are complementary to the sticky ends of the DNA fragment containing gene

3) The vector DNA and DNA fragment are mixed together with DNA ligase
-DNA ligase joins the sugar-phosphate backbones of the two bits of DNA. Process called ligation

4) New combination of bases in the DNA (vector DNA + DNA fragment) is called recombinant DNA

Question 6

Part 3 of Genetic engineering- Transforming the cells

Answer 6

The vector with the recombinant DNA is used to transfer the gene into the bacterial host cells.

If a plasmid vector is used, the host cells have to be persuaded to take in the plasmid vector and its DNA.
This could be done by using electroporation.

Bacteriophage vectors infect the host bacteria by injecting its DNA into it. The phage DNA will integrate into the bacterial DNA.

Question 7

Electroporation process

Answer 7

A suspension of bacterial cells is mixed with the plasmid vector and placed into an electroporator.
When it is switched on, an electrical field is created in the mixture which increases the permeability of the bacterial cell membrane (as pores open) so they take up the plasmids.
-Pores then reseal after electric pulse ends. DNA remains in cell

Question 8

Technology transfer is…

Answer 8

is the sharing of knowledge, skills and technology.

Question 9

A patent is …

Answer 9

a document giving you legal protection to an invention, for example a genetically modified product.

Question 10

Process of creatinginsect resistant soy bean plants

Answer 10

1)Desired DNA isolated from Bt (bacterium containing gene that codes for a protein that is toxic to some insects) Using restriction enzymes and is inserted into the plasmid
2)plasmid put back into
3)Soybean plant cells infected with bacteria.
Desired gene inserted into plant cells DNA
=GM plant

Question 11

Positive ethical issues of using GM plants

Answer 11

-Will reduce amount of chemical pesticides farmers use on crops which can harm the environment

-GM plants can be designed to be more nutritious

Question 12

Negative ethical issues of using GM plants

Answer 12

-May encourage monoculture which decreases biodiverdity, making the entire crop vulnerable to disease as all grenetics are identical

-GM soybeans could interbreed with wild plants and produce superweeds - weeds that are resistant to herbicides

Question 13

Negative ethical issues of using GM plants

Answer 13

-May encourage monoculture which decreases biodiversity, making the entire crop vulnerable to disease as all genetics are identical

-GM soybeans could interbreed with wild plants and produce superweeds - weeds that are resistant to herbicides

Question 14

positive ethical issues of Pharming

Answer 14

Drugs are made in large quantities compared to other methods

=More available

Question 15

negative ethical issues of Pharming

Answer 15

ETHICS
-harmful side effects for animal?
-Reinforce idea that animals are assets to use

Question 16

Positive ethical issues of Using Pathogens for research

Answer 16

-Reduce suffering because previously untreated diseases now treated

Question 17

Negative ethical issues of Using Pathogens for research

Answer 17

-Researchers infected by pathogen they’re researching + cause outbreak
-GM version of pathogen could convert back into original form + cause outbreak
-Biowarfare

(these are unlikely as there are strict protocalls)

Question 18

Gene therapy

Answer 18

Gene therapy involves altering alleles to cure/ease the symptoms of genetic disorders e.g cystic fibrosis.

Question 19

during Gene therapy, If disease is caused by a recessive allele a _____ _____ allele is added.

Answer 19

working dominant

Question 20

during Gene therapy, If disease is caused by a Dominant allele, the allele is ………

Answer 20

silenced by adding a non-coding section of DNA into it.

Question 21

Autosomal –

Answer 21

A non sex chromosome (in Humans chromosomes 1 – 22).

Question 22

Recessive

Answer 22

Two copies of allele are needed to show the phenotype.

Question 23

Mutation –

Answer 23

A change in the base sequence of DNA. Can be deletion, addition or substitution.

Question 24

Gene

Answer 24

A section of DNA that codes for a polypeptide.

Question 25

Gene Therapy Can be _____cell or ____ ____.

Answer 25

somatic or germ line.

Question 26

How can we insert DNA into a cell?

Answer 26

Use a vector!
Plasmids
Virus
Liposomes ( spheres made of lipids)

Question 27

Somatic cell therapy

Answer 27

Involves altering alleles in body cells, particularly those most affected by the disorder.
It does not affect the offspring
E.g In CF, somatic therapy targets the epithelial cells lining the lungs.

Question 28

Germ line therapy

Answer 28

Altering the alleles in the sex cells. Means that every cell of any offspring produced will be affected by gene therapy so won’t inherit the disease.
Currently, germ line therapy is illegal in humans.

Question 29

4 Advantages of gene therapy

Answer 29

Could prolong lives of people with life-threatening genetic disorders

Can give people with genetic disorders a better quality of life- eases symptoms

GL therapy would allow carriers of genetic disorders to conceive a baby without disorders

Could decrease the number of people with disorder in population  less people require treatment so less strain on NHS

Question 30

any 4 from Disadvantages of gene therapy

Answer 30

Body could start an immune response against vectors

Allele could be inserted in the wrong place, causing more problems e.g cancer

An inserted allele could get overexpressed, producing too much of the protein which can cause other problems

Effects of treatment may be short-lived with somatic therapy so may have to undergo multiple treatments

May be difficult to get the allele into specific body cells

Could potentially be used in ways other than medical treatment e.g anti-ageing treatments

Potential to do more harm than good

Expensive- could it be better spent on treatments that have passed clinical trials?

Question 31

explain how scientists can determine the success of inserting the plasmid into the bacterium

Answer 31

Use of a marker gene

(genes for) fluorescence

(examine fluorescence under) UV light

or
Antibiotic resistance gene
Grow on agar containing antibiotic

Question 32

what needs to be done with the mRNA tha codes for insulin in order for the rest of the genetic modification to take place

Answer 32

-Make single stranded DNA/Complementary DNA
-Using reverse transcriptase
-Make double-stranded DNA using DNA polymerase

Question 33

state one valid concern that people have about the GM of bacteria

Answer 33

(increase in antibiotic) resistance

Question 34

explain how inserting a new gene into a chromosome could affect her functioning of other genes in that chromosome

Answer 34

-Frameshift

-Altered triplets

-Adjacent/nearby genes (on same chromosome) switched on/off

-idea that new gene could disable a functioning gene if inserted into it

Question 35

Huntington’s disease is lethal and caused by a dominant allele that codes for a protein huntingtin

Suggest why gene therapy is unlikely to work as a treatment for Huntington’s disease

Answer 35

protein/ Huntingtin still synthesized/present

*( Alleles are dominant because they synthesize a particular protein and would continue to do so in presance of healthy allele

Question 36

Huntington’s disease is lethal and caused by a dominant allele that codes for a protein huntingtin

Suggest why gene therapy is unlikely to work as a treatment for Huntington’s disease

Answer 36

protein/ Huntingtin still synthesized/present

*( Alleles are dominant because they synthesize a particular protein and would continue to do so in presence of healthy allele