chapter 22 Flashcards
what is natural cloning
a structure that forms off a plant that then becomes its own differentiated new plant that is genetically identical to the parent
benefit of vegetative propagation involving perennating organs
a perennating organ stores enough nutrients to sustain the organism during the unfavourable season
4 ways natural plant cloning occurs
bulbs
runners
rhizomes
stem tubers
how does bulbs cause natural cloning
leaf bases swell with stored food from photosynthesis (perennating organ). buds form internally which develop into new shoots and new plants in the next growing season
how do runners cause natural cloning
a lateral stem grows away from the parent plant and roots develop where the stem touches the ground. a new plant develops - the runner eventually withers away leaving the new individual independent
how do rhizomes cause natural cloning
a rhizome is a specialised horizontal stem running underground, often swollen with stored food. buds develop and form new vertical shoots which become independent plants
how do stem tubers cause natural cloning
the tip of an underground stem becomes swollen with stored food to form a tuber or storage organ. buds on the storage organ develop to produce new shoots
plant cuttings
cutting off non-flowering stem from budding plant, dipping it in plant hormones root powder, to encourage growth, fungicide, to prevent infection, and then growing in soil
micropropagation
taking only a tissue sample, sterilising it (e.g with ethanol) and growing w hormones (auxins and cytokines) on agar until roots have developed. a callus forms and this is split into cells and transferred to a new agar plate and eventually, the small plantlets that form and pitted in soil
advantages of micropropagation
- rapid production of plants
- creates disease-free plants
- can clone seedless plants, like seedless varieties of grapes
- produce large numbers of rare/endangered plants
- can grow plants that do not grow from seeds easily
disadvantages of micropropagation
- expensive and requires skilled workers
- if original cells have a viral infection, all the plants produced will have the virus too
- monocultures are grown and the gene pool is reduced, so all the plants are susceptible to the same diseases
embryo splitting
- two parents w desired characteristics, such as two healthy cows w a female that produces nutrient-rich milk, are selected
- the female is given hormones to make her produce many eggs
- samples of their eggs and sperm are used for IVF, or sometimes the eggs are naturally fertilised
- embryo formed is split apart into many single, identical cells
- these are inserted into the uterus of different host mothers and all the offspring would be clones of each other (not the parents)
somatic cell nuclear transfer
- somatic cell is taken from animal to be cloned
- an egg cell is taken from a female and the nucleus is removed and discarded
- the nucleus is then removed from somatic cell and inserted into empty egg cell
- small electrical current is applied to make egg cell start to divide
- once the embryo is a bundle of cells, the cells are separated and inserted into the uterus of different host mothers
- each of these inserted cells are genetically identical to each other and the animal it came from
advantages of animal cloning
- animals w desirable characteristics will produce more offspring than w natural reproduction
- SCNT enables genetically engineered embryos to be cloned
- it could be used to increase the numbers of rare and endangered animals
disadvantages of animal cloning
- SCNT is not efficient, usually 1 embryo is formed from many eggs
- there is a high miscarriage rate when implanting embryos from SCNT
- animals produced by SCNT often have a shorter lifespan
microorganism have been used to make the following foods:
bread - when yeast respires they produce CO2
brewing - yeast respires anaerobically producing ethanol
cheese - bacteria use lactose in milk as respiratory substrate causing the milk to separate into curds and whey, curds is used to make cheese
yoghurt - bacteria produce ethanol or lactic acid resulting in the milk forming polymers that give yoghurt a thicker and smooth texture
mycoprotein (Quorn) - the fungus
/Fusarian venetatum/ is grown and used ti make Quorn
reasons for using microorganisms in food production
economics - microbes are small and so can be grown in smaller spaces than animals + nutrient requirement is cheaper than animals. temperatures they grow are are low so harvesting them is cheaper
short life cycle - bacteria can reproduce every 20 minutes, therefore food production is faster than waiting for animals to grow
growth requirements are basic, reducing the cost and making it easier to grow them. they only need warmth, water, oxygen, and food
medicines produced by microorganisms
penicillin - antibiotic produced by the mould /Penicillium notatum/, /Penicillium chrysogenum/ is now used as it results in a higher yield of penicillin. fungus is grown in fermenters, stirred w oxygen and nutrients and penicillin produced is harvested and purified
insulin - produced by genetically modified bacteria which have the human gene for insulin inserted into one of their plasmids
bioremediation
use of microorganisms to digest pollutants and contaminants. naturally occurring microbes break down pollutants like sewage and crude oil. microbial growth can be encouraged to increase in population size to help break down pollution. technique is commonly used on contamination sites (e.g. oil spills). scientists are looking at genetically modifying bacteria to increase range of pollutants they can break down
advantages of using microorganisms in biotechnology
- microbes grow rapidly
- microbes can be genetically engineered
- microbes can be flavoured to taste like anything
- no ethical concerns about growing microbes
- microbes are rich in protein and low in fat
disadvantages of using microorganisms in biotechnology
- microbes can also produce toxins if growing conditions are not carefully controlled
- microbes must be grown in aseptic conditions
- some people dont like the idea of eating microns
- microbes have no natural flavour, so additives have to be used
4 stages in growth curve
- lag phase - bacteria population is low to begin with
- exponential/log phase- numbers of bacteria is rapidly increasing
- stationary phase
- death phase - when nutrients run out or toxins build up
no death phase usually in open systems as nutrients are constantly being replaced
immobilised enzymes
when the enzyme is fixed to inert substance and substrate is passed over it
no need to purify the enzyme from product at the end of the, therefore they can be reused (economically beneficial), less sensitivity to changes therefore higher temperatures can be used increasing RoR without denaturing the enzymes
4 methods of using immobilised enzymes
- surface immobilisation - adsorption to inorganic carrier
- surface immobilisation- covalent or ionic bonding to inorganic carriers
- entrapment- in matrix e.g. polysaccharides, gelatin, activated carbon
- encapsulation - trapping enzyme within membrane or capsule
