A Level Biology OCR > Genetic Engineering > Flashcards

Genetic Engineering Flashcards

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1
Q

What is genetic engineering

A

The manipulation of the genome

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2
Q

What is a transgenic organism

A

AN organism that carries a gene from another organism is a transgenic organism

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3
Q

What is another name for a transgenic organism

A

A GMO

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4
Q

What is used in the most common technique for isolating the desired gene

A

The use of enzymes called restriction endonucleases to cut the required gene from the DNA of an organism

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5
Q

What is another technique for isolating the desired gene

A

Isolating the mRNA for the desired gene and using the enzyme reverse transcriptase to produce a single strand of complementary DNA

DNA polymerase is then used to convert the single stranded cDNA to double stranded cDNA

Restriction endonuclease enzymes then cut the desired gene and plasmid

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6
Q

What are the advantages of using the mRNA technique

A

It’s easier to identify the desired gene of a particular cell that will make some very specific types of mRNA

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7
Q

What are the most common vectors used in genetic engineering

A

Bacterial plasmid

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8
Q

What is a recombinant plasmid

A

Once a plasmid gets into a new host cell it can combine with the host DNA to form recombinant DNA

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9
Q

What must occur to insert the fragment into the plasmid

A

The plasmid must be cut open

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10
Q

What is a feature of the restriction endonucleases used to isolate the DNA fragments and plasmid

A

The same restriction endonucleases used is used to isolate the DNA fragments and to cut open the plasmid

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11
Q

Why is the same restriction endonucleases used used to cut open the plasmid and the DNA fragments

A

As it results int he plasmid having the same sticky ends as the ends of the DNA fragment

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12
Q

What is required to join together the sticky ends of the plasmid and DNA fragment and what does it

A

DNA ligase forms phosphodiester bonds between the sticky ends of the plasmid and DNA fragments, joining them together

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13
Q

Why aer plasmids often used as vectors

A

As they contain marker genes, which enables scientists to determine whether the bacteria has taken up the plasmid, by growing it in the medium containing the antibiotic

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14
Q

What is a feature of the marker genes

A

It is often placed in the plasmid by genetic engineering methods

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15
Q

Where is the desired gene placed in the plasmid with the marker genes

A

The plasmid is cut by restriction endonucleases within the marker genes to insert the desired gene.

If the DNA fragments is inserted correctly the marker genes will not function as it’s inserted inside of it.

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16
Q

What was a feature of what marker genes coded for in the past and compare to now

A

In the past the marker genes were usually for antibiotic resistance however due to concerns about antibiotic resistance they have been changed to fluorescence or an enzyme that causes a colour change in a particular medium.

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17
Q

What occurs to the plasmid once it has been engineered

A

It can be grown in a culture

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18
Q

What is a feature of the plasmid with the recombinant DNA

A

It must be transferred into the host cell in a process called transformation

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19
Q

What is one method of transformation

A

To culture the bacerial cells and plasmids in a calcium solution and increase the temperature causing the bacterial membranes to become permeable and the plasmids to enter

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20
Q

What is the second method of Transformation

A

Electroporation

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21
Q

What is electroporation

A

When a small electrical current is applied to the bacteria, making the membranes porous and so plasmids move into the cells

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22
Q

What are other uses of electroporation

A

It can be used to get DNA fragments directly into eukaryotic cells. The new DNA will pass through the cell membrane and the nuclear membrane to fuse with the nuclear DNA.

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23
Q

What is a negative of electroporation

A

Due to the strength of the electric current it could permanently damage or destroy the whole cell

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24
Q

What is electrofusion

A

A current is applied to the membrane of two different cells fusing the cells and nuclear membranes of the two different cells together to form a hybrid polyploid cell containing DNA from both.

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25
What is electrofusion used for in animals cells
To produce monoclonal antibodies
26
What is a monoclonal antibodies
The combination of a cell producing a single type of antibody and a tumour cell This allows it to rapidly divide in the culture
27
What are monoclonal antibodies used for
Identifying pathogens in animals and plants, and in the treatment of diseases
28
What is the order of the easiest organism to genetically modify to the hardest
Easiest - prokaryotes, plants, then animals
29
What have bacteria been genetically modified to produce
Many different substances that are useful - e.g Insulin and human growth hormone
30
What is one method of genetically modifying plants
Agrobacterium tumegaciens
31
How are plants genetically modified with agrobacterium tumefaciens
A desired gene is placed in the Ti plasmid of the bacteria, along with a marker gene - This is then carried into the plant cell DNA. The transgenic plant cells form a callus which is a mass of plant cells, each of which can be grown into a new transgenic plant
32
what are features of transgenic plants be produced by electrofusion
The cells produced have chromsomes from both of the original cells and so are polyploid. The cells can be fused together from similar species or very different ones
33
What are the main stages of producing transgenic plants via electrofusion
The removal of the plant cells produced wall by celluloses, electrofusion to form a new polyploid cell and the use of plant hormones stimulating the growth of a new plant cell followed by callus formation. Many transgenic plants are then produced
34
Why is harder to manipulate the DNA of eukaryotic animals
Because animal cell membranes are harder to manipulate compared to plant cells membranes.
35
What are Soya beans and what are features of the crop
They are a major world crop - with 250 million tonnes being produced a year and half are from GM strains
36
How have the soya bean been genetically modified.
They have inserted a gene into the soya beans so that they produce the BT protein
37
What is the BT gene
It is toxic to many of the pests attracted to the plant and is wildely used as a pesticide
38
What has one strain of soya bean been genetically engineered for and what has this allowed farmers to do
To be resistant to a common weed killer and contain the BT protein This allows for farmers to spray to get rid of weeds allowing for maximum crop yields and not need pesticides
39
What is a negative of using a gene for antibiotic resistance in the bacteria
There is a perceived risk that the resistance could spread to the wild populations of plants and into bacteria.
40
What are the advantages of genetic engineering an organism for pest resistance
Pest-resistance GM crops reduce the amount of pesticide spraying protecting the environment and helping poor farmers Increases the yield
41
What are the disadvantages of genetic engineering an organism for pest resistance
Non-pest insects and insect-eating predators may be damaged by the toxins in GM plants Insect pests may become resistant to pesticides in GM crops
42
What are the advantages and disadvantages of genetic engineering an organism for disease resistance
Crop varieties resistant to plant diseases can be produced, reducing crop losses/ increasing yield. Transferred genes might spread to wild populations and cause problems.
43
What are the advantages and disadvantages of genetic engineering an organism for herbicide resistance
Herbicides can be used to reduce competing weeds and increase yield Biodiversity could be reduced if herbicides are overused to destroy weeds. Fear of superweeds.
44
What are the advantages and disadvantages of genetic engineering an organism for extended shelf life
The extended shelf life of some GM crops reduces food waste Extended shelf-life may reduce the commercial value and demand for the crop
45
What are the advantages of genetically engineering a crop for growing in a wider range of conditions
Crops can grow in a wider range of conditions/survive adverse conditions
46
What are the advantages and disadvantages of genetically engineering a crop for nutritional value
Nutritional value of the crops would be increased People may be allergic to different proteins made in GM crops
47
What are the advantages of genetically engineering a crop for medical uses
plants could be used to produce human medicines and vaccines.
48
What is a problem with patents of GMOS
People in less economically developed countries will be prevented from using them by patents and issues of technology transfer. Resulting in people who most need the benefits may be unable to afford the GM seeds.
49
What do people in less economically developed countries also require to do with seeds
They rely on harvesting seed from one year to plant the next - something patenting rules make impossible
50
What is it much harder to produce compared to plants but what are scientists doing now instead of
GM vertebrates - however scientists are using micro injections and modified viruses to carry new genes into animal DNA
51
What are examples of GM animals
Swine fever resistant pigs - where scientists inserted a gene from wild African pigs into a European pig strain giving them immunity to the fatal African swine fever Faster growing salmon - Atlantic salmon have been given genes from chinook salmon, so they produce growth hormone all year round. Allowing them to grow to full adult size in half the time of conventional salmon
52
What is pharming (1)
The creation of animal models - via the addition or removal of genes so that animals develop certain diseases, acting as models for the development of new therapies.
53
What is pharming (2)
Creating human proteins - via the introduction of a human gene coding for a medically required protein
54
Why are animals used instead of bacteria in pharming
Add sometimes the bacteria can’t produce all of the complex proteins made by a eukaryotic cell
55
How can the gene be introduced in the animal in pharming
It can be introduced into the genetic material along with a promoter sequence so that the gene is only expressed in the mammary glands
56
What can the animal mature to do in pharming
To produce milk with the desired proteins
57
what are the ethical issues around pharming (1)
Should animals be genetically engineered to act as models for human disease Is it right to put human genes into animals Is it acceptable to put genes from another species into animals animal without being certain it will not cause harm
58
what are the ethical issues around pharming (2)
does genetically modifying animals reduce them to commodities Is welfare compromised during the production of genetically engineered animals
59
What is somatic cell therapy
The replacing of a mutant allele with a healthy allele in the affected body cells
60
What are the negatives of somatic cell gene therapy
It is only a temporary solution for the treated individual as the healthy allele will be passed on every time the cell divides, however they will eventually be replaced by stem cells which contain the faulty allele.
61
What is the alternative to somatic cell therapy
The insertion of a healthy allele into the germ cells - or an embryo immediately after fertilisation The individual would be born healthy and would pass it on to their own offspring
62
What is: the insertion of a healthy allele into the germ cells - or an embryo immediately after fertilisation
Germ line cell gene therapy
63
What has germ line gene therapy been done in and not done in
it has been done in animal embryos but is illegal to do in human embryos due to ethical and medical concerns
64
What are the ethical and medical concerns surrounding germ line cell gene therapy
The potential impact on a germ cells of an intervention is unknown. The human rights of the unborn baby could be said to be violated. It could also lead to certain features being put into the germ that are desirable.
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