biotechnology Flashcards
Why are plants important?
biodiversity, paper/wood products, textiles/fibres, food and fodder, pharmaceuticals, petroleum substitutes, amenity
What is plant biotechnology?
plant cell factories, plant tissue cultures, transgenic plants, molecular breeding, food processing, plant breeding and wine making
What was the green revolution?
a planned international effort in the 1970s to increase crop yield through: new crop cultivars, irrigation, fertilisers, pesticides, mechanisation
What did the green revolution do?
reduced chronic hunger from 40% to 20% of the world population while the population has double and saved millions of hectares of land from cultivation
What did plant breeding and the green evolution achieve?
faster growth, semi dwarf habit (strong stems that don’t fall over), higher yield, disease resistance, adaptability to local conditions
How can biotechnology help?
some plants can be regenerated from a cutting. many plants can regenerate from a few cells but only if the right hormones are provided
How can biotechnology help?
some plants can be regenerated from a cutting. many plants can regenerate from a few cells but only if the right hormones are provided
Why is plant tissue culture useful?
micropropagation, eliminating systemic viruses
What is molecular breeding?
find a DNA marker that is closely linked to the fruit character, follow it in the progeny of a cross, use the marker to identify the seedlings that will bear a certain fruit
What is molecular breeding?
find a DNA marker that is closely linked to the fruit character, follow it in the progeny of a cross, use the marker to identify the seedlings that will bear a certain fruit
How do we find the markers for molecular breeding?
generate a fingerprint of the parent plant using random DNA markers, find markers that are linked to the phenotype, check that the linkage is close, use markers to identify the plants at the seedling stage
What is protoblast fusion?
treat plant tissue with enzymes to remove cell wall, create protoblasts, fuse protoblasts with different genotypes, use polyethylene glycol or electric pulse, tool for creating wide crosses between similar but different species
What is embryo rescue?
culture embryos that would otherwise die
How to use plant cells as factories?
understand the biochemistry, find the genes, express them in the plant cells, harvest the chemicals
What are problems to overcome using plant cells as factories?
they might de-differentiate so changes in gene expressed, changes in enzymes produced and changes in metabolites produced
What is the percentage of essential drugs that are exclusively of flowering plant origin?
11% of 252
What is taxol?
potent anti-cancer drug which binds microtubules and stops cell division
How is plant transformation done?
assemble a transgene in a bacterial plasmid, transfer to the plant genome, select plants with new traits
How is plant transformation done using Agrobacterium tumefaciens?
it is a plant pathogen who’s disease is crown gall, bacterium delivers its own plasmid DNA into plant genome, one gene codes for an enzyme to make the plant hormone cytokinin - replace genes which cause crown gall with transgenes and insert these into plant chromosomes
What is Agrobacterium leaf disc transfer?
put transgene into Agrobacterium, incubate Agrobacterium with the leaf discs, move leaf discs onto selective medium, wait for shoots and roots to develop, grow plants on to maturity
How are plants regenerated from tissue culture?
incubate leaf with discs of Agrobacterium, balance cytokinin and auxin, add more cytokinin to induce shoot growth, add more auxin to induce root growth, transfer to soil and gradually reduce humidity
What is a transgene?
it is made up of a promotor (can only come from something that will react with plant machinery) and a coding region (from any organism)
How is a transgene assembled?
inside a plasmid, promotor and coding region are spliced together to form a transgene which is then transferred to the plant genome
How can GM plants help?
increased crop plant yields due to protection from pests and pathogens, improvement of nutritional qualities (vitamins, proteins, antioxidants), new products (vaccines, plastics)
How much do pests and pathogens reduce crop yield by?
30%
How much does insect damage reduce crops by?
13%
What bacterium is toxic to insects and why?
Bacillus thuringiensis because it produces protein crystals
How can this be used to make plants resistant to insects?
Bt toxic proteins identified, genes isolated, cloned into plasmids, transformed into plants
How can a plant be protected from potato virus Y?
clone virus protein coat, transform into plants, causes protection and healthy crop
What does vitamin A deficiency cause?
blindness
What is rice very poor in>
beta carotene needed for synthesis of vitamin A
How many children go blind every year?
250,000-500,000