6.2.1- Cloning and Biotechnology Flashcards
what is cloning?
A method of producing genetically identical offspring by asexual reproduction.
what are clones?
genetically identical copies of genes, cells or organisms
what is reproductive cloning?
the production of genetically identical individuals
how do prokaryotes clone themselves naturally?
by binary fission (cells split in two)
how do eukaryotes clone themselves naturally?
by asexual reproduction (divide by mitosis)
what is asexual reproduction known as in plants?
vegetative propagation
how do plants clone themselves naturally?
by growing new plants from growing points (meristem), which contain undifferentiated stem cells that are capable of dividing and differentiating to produce new individual plants called cuttings
what are the three advantages of using asexual reproduction for natural cloning?
1- Rapid colonisation (saves time finding mate and producing gametes)
2- Allows reproduction in absence of mates
3-All offspring are well-adapted to current environment
what is the disadvantage of using asexual reproduction for natural cloning?
no genetic variation/diversity
what is vegetative propagation?
any form of asexual reproduction that occurs in plants, where a new plant grows from a fragment of the parent plant or specialised reproductive structure
what are four examples of vegetative propagation?
-bulbs, daffodil= the leaf bases swell with stored food for photosynthesis
-runners, strawberries= lateral stem grows from the parent plant, roots develop when it touches the ground
-rhizomes, marram grass=horizontal stem running underground, swollen with stored food
-stem tubers, potato= tip of underground stem becomes swollen into stored food and forms a tuber, the buds on the tuber develop to produce new shoots
what are the 3 techniques of horticulture and explain these?
1= cuttings, cut stem treated with plant hormones
2= grafting, cut stem inserted into groove on a different plant stem
3= splitting bulbs, splitting up bulbs or cutting up rhizomes.
what are some advantages of using cuttings to crop plants rather than using seeds?
-all plants will be the same (height, size, flowering, etc) to the stock plant
-guarantees quality
-much faster time from planting to cropping
what are some disadvantages of using cuttings to crop plants
-decreases genetic diversity
-if one plant is effected by disease, they all will be
why should cuttings be taken at an angle?
-greater surface area
-increased water uptake
-enhances survival
is horticulture natural or artificial cloning?
artificial
how does vegetative propagation occur in elm trees?
-elm tree roots contain meristem tissue which divides by mitosis to produce root suckers, which do not usually survive in crowded woodland due to competition for sunlight
-if the main trunk is destroyed during disease, burning or felling, a ring of root suckers starts to grow called a clonal patch
what is the disadvantage of vegetative propagation in elms?
suckers are just as susceptible to diseases as the original tree, as they are genetically identical
what is the main advantages of vegetative propagation in elms?
-survive burning and felling
-recolonise rapidly
what are the 6 steps to taking plant cuttings used in horticulture?
1-use a non-flowering stem
2-make an oblique cut with a sharp scalpel
3-use a hormone rooting powder
4-reduce leaves
5-keep cutting well watered
6- cover the cuttings with a plastic bag
explain the steps in taking plant cuttings used in horticulture?
1-so resources are used to grow the roots
2-large sa, sharp to prevent cell damage
3-synthetic auxins, to allow adventitious roots to grow
4- less stress on plant so increases survival
5- has no roots to absorb water, ensures survival
6-humidity, stops plant drying out and reduces water loss
what is another example of artificial cloning in plants?
micropropagation/tissue culture
what is micropropagation/tissue culture?
the process of making large numbers of genetically identical offspring from a single parent plant using tissue culture techniques.
when is tissue culture used?
-plants that do not readily produce seeds
-plants that do not respond well to natural cloning
-rare plants
-plants that have been genetically modified or selectively bred with difficulty
-plants required to be ‘pathogen free’