3.5 Genetics and Biotechnology Flashcards
Explain the benefits of GMOs.
Health Benefits:
- increased nutritional value of crops, crops without allergic reaction
Environmental Benefits:
- less insecticide needed, shelf life of crops extended
Agricultural benefits:
- varieties resistant against drought , high salinity, increased yield, resistance against certain viruses, fugi, etc.
Explain the risks of GMOs.
Health risks:
- allergic reactions, enhanced antibiotic resistance, unexpected effects of ‘new proteins’
Environmental risks:
- non-target organisms affected by toxins, crop herbicide-resistant genes could spread to other plants
Agricultural risks:
- restrictions on farmers reusing seed, increased resistance in insects/other pests
Outline a technique used for gene transfer. [5 marks]
a. plasmid used for gene transfer and is removed from bacteria
b. plasmid is a small circle of DNA
c. restriction enzymes cut DNA of plasmid at specific base sequence, creating sticky ends d. same restriction enzyme used to cut DNA with desired gene
d. DNA can be added to the sticky ends, joining gene and plasmid
e. DNA ligase used to join together
f. recombinant DNA is inserted into host cell
What benefits are relevant and need assessing for Bt Corn?
General Potential benefits:
- introduction of a new trait - Bt gene increases resistance to pests such as the European Corn Borer
- results in increased productivity - less land used/ greated yield/ less crop damage
- decrease use in chemical pesticides - reduced cost/ ecological damage to wild the economic cost of farming
Risks of Bt Corn.
General Potential Risks
- could be toxic to or cause allergic reactions in humans
- non-target organisms affected by toxins
- increases resistance to toxin evolves in pests
- accidental release may result in competition with native plant species
- superweeds develop - through sexual transmission the introduced gene could be transferred to wild varieties
- biodiversity reduced as those that feed on corn are killed
Which is a possible risk associated with genetic modification of crops?
A. Crop plants will become weaker with time.
B. It can increase mutations in the organisms that consume them.
C. Starch obtained from genetically modified plants will be more difficult to digest.
D. Resistance to herbicide genes can be transferred to weeds.
D. Resistance to herbicide genes can be transferred to weeds.
Explain benefits and risks of using genetically modified crops for the environment and also for human health. [8 marks]
Environment benefits:
a. pest-resistant crops can be made
b. so less spraying of insecticides/pesticides
c. less fuel burned in management of crops
d. longer shelf-life for fruits and vegetables so less spoilage
e. greater quantity/shorter growing time/less land needed
f. increase variety of growing locations / can grow in threatened conditions
Environment risks:
g. non-target organisms can be affected
h. genes transferred to crop plants to make them herbicide resistant could spread to wild plants making super-weeds
i. GMOs (encourage monoculture which) reduces biodiversity
j. GM crops encourage overuse of herbicides
Health benefits:
k. nutritional value of food improved by increasing nutrient content
l. crops could be produced that lack toxins or allergens
m. crops could be produced to contain edible vaccines to provide natural disease resistance
Health risks:
n. proteins from transferred genes could be toxic or cause allergic reactions
o. antibiotic resistance genes used as markers during gene transfer could spread to «pathogenic» bacteria
p. transferred genes could cause unexpected/not anticipated problems
OR
health effects of exposure to GMO unclear
Bt Corn risks to monarch butterflies
Context:
- caterpillar stage of the Monarch feed on milkweed, milkweed commonly grows on the edge of corn fields, studies show some mortality in Monarch caterpillars fed milkweed leaves covered with Bt corn pollen
Define a clone.
A group of genetically identical organisms. A group of cells derived from a single parent cells.
Monozygotic Twins
Are naturally occuring clones. eg. when a starfish loses a leg they are able to regenerate a whole body from a single leg.
Describe and explain the process somatic cell nuclear transfer (SCNT)
- cloning multicellular organisms requires the rpoduction of stem cells (differentiated cells cannot form other cell types)
- stem cells can be artificially generated from adult tissue using SCNT
- Somatic cell nuclear transfer is a method by which cloned embryos can be produced using differentiated adult cells
- Somatic cells are removed from the adult donor and cultured (they are diploid and contain the entire genome)
- an unfertilised egg is removed from a female adult and its haploid nucleus is removed to produce an enucleated egg cell
- the enucleated egg cell is fused with the nucleus from the adult donor to make a diploid egg cell with donor’s DNA
- an electric current is then delivered to stimulate the egg to divide and develop into an embryo
- The embryo is then implanted into the uterus of a surrogate and will develop into a genetic clone of the adult donor
Natural methods of cloning
species can reproduce asexually and hence possess natural methods of cloning
- all bacteria - majority of fungi and many species of protists reproduce asexually to produce genetic clones
- while most plants reproduce sexually, they also possess methods of asexual reproduction
- certain animal species can also reproduce asexually, via a variety of different mechanisms
Animal cloning methods - Binary Fission
- parent organism divides equally in two, so as to produce two genetically identical daughter organisms
- this method of cloning occurs in Planaria (flatworms) but is also common to bacteria and protists
Animal cloning methods - budding
- cells split off the parent organism, generating a smaller daughter organism which eventually separates from the parent
- this methods of cloning occurs in Hydra but is also common to many species of yeast
Animal cloning methods - Fragmentation
- New organisms grow from a separated fragment of the parent organism
- This method of cloning is common to starfish and certain species of annelid worms
