plants and intro

Question 1

name a synonym for genetic engineering

Answer 1

recombinant DNA

Question 2

discuss the process of genetic engineering

Answer 2

gene isolation
gene characterisation
protein characterisation
inserting/deletion

Question 3

discuss early examples of transgenisis

Answer 3

1980; first trangenic animal produced; mice with growth factor
1983; first transgenic plant; antibiotic resistant tobacco
1994; first transgenic product introduced to public; flavr savr tomato
1995; first trangenic plant introduced to public; herbicide tolerant soybean
2012; first transgenic animal declared safe to ear (17 years after registration

Question 4

discuss a recent and important technology in biotechnology

Answer 4

precise genome editing tools like CrisprCAS9, zing finger nucleases and TALENS

Question 5

discuss the uses of biotechnology

Answer 5

allows scientists to understand biological processes
new traits can be added to organism (change in phenotype); this can be useful to the agricultural industry
important proteins can be produced for use in industry such as pharmacutical, detergent,
new molecules can be produced

Question 6

what are the hard part about genetic engineering

Answer 6

getting the new cell to regenerate in the host organism

getting the product on the market; the extensive selection process normally takes about 10 years.
Golden rice which was produced in 1999 still isint on the market

Question 7

discuss facts surrounding exponentiation population increase for example where is populaiton increase occuring

Answer 7

in 1800 the population was 1billion
currently the populaiton is 7.6 billion
most population increase is from asia, some from asia. europe is stable

Question 8

how many people die from malnutrition and hunger

Answer 8

30,000 daily (50% are children)

Question 9

how much must plant productivity increase by 2040, how many additional people will there be at this time 2.3billion more

Answer 9

70%

Question 10

what are the two solutions to solving malnutrition and population increase; 5 marks

Answer 10

increase productivity by addressing bottle necks to productivity such as biotic and abiotic stress

biotic stress causes 40% of useable biomass to be lost
there has been some success in dealing with biotic stress with synthetic pesticides but these effect non target organisms so are not sustainable
dealing with abiotic stress is more complicated as it involved engineering many genes for enzymes to control complex metabolic webs

increase agricultural footprint (amount of land used for crops).

Question 11

what is the difference between 1st, 2nd and 3rd generation crops, use examples- 6 marks

Answer 11

1st; crops with traits beneficial to farmers
2nd; crops with traits beneficial to consumers; enhanced vitamin content
3rd; crops with traits that allow them to be used as biofactories; produce biofuels etc

Question 12

discuss the european stance on importing GM products: 2 marks

Answer 12

GM crops are banned

less strict with animals that have eaten GM crops

Question 13

discuss 4 examples of using biotechnology to increase productivity of crops: 10 marks

hint: 2 are biotic, 2 are abiotic

Answer 13

1) herbicide tolerance so herbicides can be used to remove weeds which are a major constraint on productivity
45% of all GM crops ate those engineered to be herbicide tolerant
soybean is the most widely grown Gm crop (edible soybean has many uses); 78% of soybean is GM and 50% of all GM crops are soybean

2)insect resistance through engineering of bacterial genes of known pathogens of insects such as B. thuringiensis
insects eat bacterial spores which causes death

3) drought tolerance engineering into cotton by altering its metabolic web
hoped to be introduced into Africa in two years

4) aluminium tolerance.
maize for example is particularly sensitive to aluminium

Question 14

discuss 4 examples of genetic engineering being used to increase health and nutrition; 8 marks

Answer 14

1) golden rice is a rice with enhanced vitamin A content
rice would normally contain no vitamin A; in asia 800 million were effected by vitamin a deficiency which led to night blindness
a few genes were added to increase the beta carotene levels in rice (pre cursor)
still not commercialised

2)Multivitamin maize (corn) which can be used as animal feed
vitamin a. b and c

3) soybean with increased omega-3 fatty acid
we currently get out omega 3 from fish which feed on alga, this is seen as economically and environmentally unsustainable
omega 3 is needed for cardiovascular health

4) crops like soybean can be engineered to express different fatty acids; healthier oils and margarines

Question 15

apart form productivity and health and nutrition, discuss other examples of plant genetic engineering; 2 marrks

Answer 15

grass which doesn’t give humans hay fever

coffee which is decaffeinated

Question 16

what are the benefits of plant biotechnology; 6 marks

Answer 16

1) food security; soybean with omega 3.
2) reduced prduction costs; 1st generation crops
3) land saving technology; less deforestion so less global wamring and no loss of biodiversity; increase productivity so the agricultural footprint doesnt have to increase. aluminium tolerant plants
4) less need for insecticide and pesticide; less environmental damage; herbicide tolerance of soybean
5) better livelihoods for farmers due to better yields. crops tolerant to bad land, better ripening times
6) crops may help lessen pollution by phytoremediation
6) the crops have qualities which are benefical to the consumer; better tasting

Question 17

what are the benefits of using genetic modification rather than conventional selective breeding; 5 marks

Answer 17

1) traits from other species can be introduced
2) very selective; only one gene transfered, not all the organisms genetic material
3) the gene can be altered to give a modified protein. synthetic genes are also an option
4) you can manipulate spatial and temporal expression so that the gene is only expressed in particular tissues
5) it allows scientists to better understand biological processes

Question 18

discuss the different methods of genetically engineering plants. state weather or not these methods are commonly used and the pros and cons of each.
suggest what future endevours may involve with GM plants

Answer 18

chemical methods
A) protoplast fusion (a protoplast is a plant cell without a cell wall); not used much
i) the cell has its cell wall degraded by cellulose enzymes, leaving a protoplast
ii) two protoplasts are then fused using either electrical or chemical treatment (PEG giving a hybrid plant cell
iii)hormones are applied to induce plant cell wall growth
iv) the cell divides into a callus and then a hybrid plant with characteristics of both plants

B) chemical phosphate; not used much

i) GOI is dissolved in phosphate buffer
ii) calcium chloride added causing the phosphate to precipitate with DNA absopbed onto it.
iii) this solution is then incubated with cells and cultured

biological methods;
A)agrobacterium tumefaciens; used often
Wounded plants release phenolics to repel microorganisms.
Agrobacterium has evolved to be attracted to phenolics; it enters the wound in the roots and transfer the T-DNA from their Ti-plasmid to be plant genome somewhere at random (phenolics also switch on virulence genes which are expressed as proteins needed to copy the plasmid)
chromosomal attatchment genes chvA and chvB are needed for this to occur
1) the genetic engineering involved removing the T-DNA from the Ti-plasmid and placing it into another binary vector (anothe rplasmid in agrobacterium), along with a marker gene such as GFP or herbicide resistance. The virulence proteins can read and copy DNA from binary vector in exactly the same way
2)smal leaf discs are incubated with agrobacterium in a selective medium which only allows transformed discs to survive
3)hormones are applied to induce root and shoot formation
good: stable transformation
bad: long process involvoing callus stage
can be used for all types of plants nowadays

B) agrobacteirum mediated floral dip; still used
1)dip flower buds in agrobacterium solution for 10 seconds
2) wrap flower in cling film for 24 hours (moist environment)
3)plant grown in growth chamber for 1 month
4) seeds extracted and grown on selective medium to select for the seeds which are transformed
this method is quick compared to the other method as the callus stage is avoided
good: very rapid

C)viral transformations; used for research
GOI engineered into a virus, which then infects plant.
the expression of the protein is not stable, and isint passed on to offspring. often only half the plant is transformed. This is a useful quick research tool though
good: research tool
bad:not stable

physical methods
A)biolistic transformation; used a lot
1) a particle gun using pressurised helium is used to shoot heavy metal particles (gold/tungsten) at an embryonic plant cell. the explosive force breaks the cell wall and the particle diffuses into the nucleus where the GOI integrates with the genome
2) cell multiplies into a callus and then a plantlet with the new trait
good: multiple genes can be introduced at once (up to 14), no plasmid backbone introduced so no concerns about complex integration patterns, very simple procedure, physical method so no limitations to the plants that can be used, no agrobacterium used so less rigorous testing (its a pathogen)
bad: plant has to regenerate

B) microinjection; not used much
DNA injected into pollen

C)liposome fusion; not used much
DNA placed in an arteficial vesicle and is released into the cytoplasm of the cell where transient expression occurs

in planta methods
A) pollen transfer
1)collect pollen
2)sonicate pollen to break down the cell wall
3)incubate pollen with agrobacterium
4)transfer pollen to female parts of plant
5)harved seeds and check for transformation
good: no tissue culture stage, very rapid so many more generations can be achieved per year
bad: efficiencyis low (2%), labour intensive, rigorous testing because agrobacterium is a pathogen

future
the use of other non pathogen bacteria with similar qualities to agrobacterium, so less testing will be required; ensifer adharens

Question 19

what are the three criteria used to check if plant transformation has occured; 6 marks

Answer 19

1) molecular genetic evidence; PCR and southern blotting to check the DNA is present
2) gene expression and phenotypic enidence; is the phenotype different, northern blots and sequence RNA (cDNA library)
3) inheritance evidence; are correct mendelian ratios adhered to; if so the transformation is likely stable and has been passed on

Question 20

discuss the 3 types of transformations; 6 marks

Answer 20

a) stable; integration into genome, trait maintaine throughout lifetime and then passed on to offspring. commercialisation
b) transient; no integration into genome, short term expression and trait is not passed on to offspring. research tool.
c) organelle; integration into plastid or mitochondria, maintained through life and then passed on maternally

Question 21

discuss how plastid transformation is done and why it may be done over nuclear transformation (discuss its 5 advantages) and also why it may not be done over nuclear transformations (its disadvantages)

Answer 21

How?

1) explant extracted (pieces of leaf) and bombarded biolistically in that hope that one or two chloroplasts will be transformed
2) the heteroplasmic cell (cell with one of its many chloroplasts transformed) has a selection pressure applied so that the wild type chloroplasts are lost and the cell becomes homoplastic. this requires several generations

Why?

1) transgene can not escape because it is not contained in seeds/pollen. no escape of genes to weeds
2) higher levels of expression; there are a large number of pladtids in a cell
3) reduced pleiotrophic effects (when one gene silences another gene) compared to nuclear transformation
5) biolistic tranformaiton benefits; no backobone, multiple insertions
6) no position effects in nucleus; expression of other genes in changed because their positions change

why not>

1) very time consuming and difficult to do; many generations
2) limited to solanaceae plants like tobacco