cloning and biotechnology Flashcards
define clones
genetically identical organisms or cells
define vegetation propagation
reproduction from vegetative parts of a plant- usually an over wintering organ
advantages of natural cloning
- if the conditions fro growth are good for the parent, then they will also be good for the offspring
- cloning is relatively rapid, so the population can increase quickly to take advantage of the suitable environment conditions
- reproduction can be carried out, even if there is only one parent and sexual reproduction is not possible
disadvantages of natural cloning
- the offspring may become overcrowded
- there will be no genetic diversity
- the population shows little variation
- selection is not possible
- if the environment changes to be less advantageous , the whole population is susceptible
describe plant cloning by vegetative propagation
the differentiation of many plant cells is not as complete as that in animals. many parts of a plant contain cells that retain the ability to divide and differentiate into a range of types of cells. this means that plants are able to reproduce by cloning. . natural cloning involves a process called vegetative propagation. this is the process of reproduction through vegetative parts of the plants , rather than through specialised reproductive structures
plant cloning by vegetative propagation
describe runners, stolons, rhizomes and suckers
many plants grow horizontal stems that can form roots at certain points .These stems are called runners or stolens if they grow on the surface of the ground, and rhizomes if they are underground. some rhizomes are adapted as thickened over wintering organs from which one or more new stems will grow in the spring
suckers are new stems that grow from the roots of a plant-these may be close to the base of a older stem or could be some distance away. in all cases , the original horizontal branch may die , leaving the new stem as a separate individual
plant cloning by vegetative propagation
describe bulbs
over an over wintering mechanism for many perennial monocotyledonous plants. bulbs consists of an underground stem from which grow a series of fleshy leaf bases. there is also an apical bud , which will grow into a new plant in the spring. often a bulb contains more than one apical bud and each will grow into a new plant
plant cloning by vegetative propagation
describe corms
corms are often mistaken for bulbs. however corms are solid rather than fleshy like a bulb. a corm is an underground stem with scaly leaves and buds. corms remain in the ground over winter. in the spring the buds grow to produce one or more new plants
plant cloning by vegetative propagation
describe leaves
the kalanchoe plant reproduces asexually , as clones grow on the leaf margins . the immature plant drops off the leaf and take root.
plant cloning by vegetative propagation
describe tubers
tubers are another type of underground stem. potatoes are tubers. one potato will grow into one or more plants. each new plant can then produce many new tubers later that year
describe cloning in animals
animals do not clone as often as plants. there are, however, a few examples of natural cloning
-mammals clone when identical twins are formed. this occurs when a fertilised egg divides as normal, but the two daughter cells then split to become separate cells. each cell grows and develops into a new individual
how to make a cutting
a stem is cut between two leaf joints( nodes) . the cut end of the stem is then placed in moist soil. new roots will grow from the tissue in the stem- usually from the node , but they may grow from other parts of the buried stem
what helps stimulate root growth
dipping the cut stem in rooting hormone
cuttings can also be made successfully from what other parts of a plant
- root cuttings- in which a section of root is buried just below the soil surface, and produce new shoots
- scion cuttings- which are dormant woody twigs
- leaf cuttings- in which a leaf is placed on moist soil. the leaves develop new stems and new roots. some leaves may produce many new plants from one cutting
describe tissue culture
many commercially grown houseplants are cloned using tissue culture techniques
tissue culture is a series of techniques used to grow cells, tissues or organs from a small sample of cells or tissues. it is carried out on a nutrient medium under sterile conditions . applications of plant growth substances at the correct time can encourage the cells in the growing tissues to differentiate
tissue culture is widely used commercially to increase the number of new plants, in micropropagation
define micropropagation
growing large numbers of new plants from meristem tissue taken from a sample plant
describe the micropropagation steps
1-suitable plant material is selected and cut into smaller pieces . these are called explants. explants could be tiny pieces of leaf, stems, root or bud. meristem tissue is often used, as this is always free from virus infection
2- the explants are sterilised using diluted bleach or alcohol. this is essential to kill any bacteria and fungi as these would thrive in the conditions supplied to help the plant grow well
3- the explants are placed on sterile growth mediums containing suitable nutrients such as glucose , amino acids and phosphates. the gel also contains high concentrations of the plant growth substances auxins and cytokines. this stimulates the cell of each explant to divide by mitosis to form callus
4- once a callus has formed , it is divided to produce a larger number of smaller clumps of undifferentiated cells
5- these small clumps of cells are stimulated to grow , divide and differentiate into different plant tissues. this is achieved by moving the cells to different growth media . each medium contains different ratios of auxins and cytokinins.
5- the first medium contains the ratio 100auxins ; 1 cytokinin , and this stimulates roots to form. the second medium contains the ratio 4 axins : 1 cytokinins , which stimulates the shoots to form
6- once the tiny plantlets have been formed, these are transferred to a greenhouse to be grown in compost or soil and acclimatised to normal growing conditions
advantages of artificial cloning
- cloning is a relatively rapid method of producing new plants compared with growing plants from seeds
- cloning can be carried out where asexual reproduction is not possible . plants that have lost their ability to breed sexually can be reproduced . similarly plants that are hard to grow from seeds can be reproduced
- the plant selected will all be genetically identical to the parent plant. they will therefore display the same desirable characteristics such as high yield , resistance to a common pest or disease, or a particular colour of flower
describe artificial cloning in animals
some invertebrate species such as greenfly and water fleas have evolved the ability to clone naturally . in order species it is a rare event. therefore most cloning of animals is artificial
successful cloning starts with that are totipotent - such cells can divide and differentiate into all types of cells found in the adult organism. in animals, the only truly totipotent cells are very early embryo cells
reproductive cloning may be useful for
- elite farm animals produced by selective breeding or genetic modification
- genetically modified animals developed with unusual characteristics
what are the two main techniques to achieve cloning are
- embryo twinning
- somatic cell nuclear transfer
define embryo twinning
splitting an embryo to create two genetically identical embryos
define enucleation
removal of the cell nucleus
describe embryo splitting
1- a zygote is created by in vitro fertilisation
2- the zygote is allowed to divide by mitosis to form a small ball of cells
3-the cells are separated and allowed to continue dividing
4- each small mass of cells is placed into the uterus of a surrogate mother
define somatic cell nuclear transfer
a technique that involves transferring the nucleus from a somatic cell to an egg cell
describe somatic nuclear transfer steps
1- an egg is obtained and its nucleus is removed , known as enucleation
2- a normal body cell from the adult to be cloned is isolated and may have the nucleus removed
3-the complete adult somatic cell or its nucleus is fused with the empty egg cell by applying an electric shock
4- the shock also triggers the egg cell to start developing , as through it has just been fertilised
5-the cells undergo mitosis to produce a small ball of cells
6- the young embryo is placed into the uterus of a surrogate mother
what is non reproductive cloning
is the production of cloned cells and tissues for purposes other than reproduction
describe therapeutic cloning
new tissues and organs can be grown as replacement parts for people who are not well
- skin can be grown in vitro to act as a graft over burned areas
- cloned cells have been used to repair damage to the spinal cord of a mouse of a mouse and to restore the capabilities to produce insulin in the pancreas
- there is the potential to grow whole new organs to replace diseased ones
tissues grown from the patients own cells will be genetically identical and so avoid rejection , which is a problem when transplanting donated organs
describe cloning for scientific research
cloned genetically identical embryos can be used for scientific research into the action of genes that control development and differentiation . they can also be used to grow specific tissues or organs for use in tests on the effects of medicinal drug
arguments for artificial cloning
- can produce a whole herd of animals with a high yield or showing an unusual combination of characteristics
- produces genetically identical copies of very high value individuals retaining the same characteristics
- using genetically identical embryos and tissues for scientific research allows the effect of genes and hormones to be assessed with no interference from different genotypes
- testing medicinal drugs on cloned cells and tissues avoids using animals or people for testing
- can produce cells and tissues genetically identical to the donor , for use in repairing damage caused by disease or accidents
- individuals from an endangered species can be cloned to increase numbers
arguments against artificial cloning
- lack of genetic variation may expose the herd to certain disease or pests
- animals may be produced with little regards to their welfare , which have undesirable side effects such as meat producing chickens cant walk
- the success rate of adult cells cloning is very poor and the method is a lot more expensive than conventional breeding. cloned animals may be less healthy and have shorter ethical issues
- ethical issues regarding how long the embryos survives and whether it is right to create a life simply to destroy it
- this does not help increase genetic diversity
define biotechnology
the use of living organisms or parts of living organisms in industrial processes. this could be to produce food, drugs or other products
recent examples of biotechnology include
- the use of bacterium clostridium acetobutylicum to produce acetone , which was needed to make explosives during ww1
- the manufacturer of penicillin from the fungus penicillium notatum during ww2
what are the four main areas in which microorganisms are used in biotechnology
- food
- pharmaceutical drugs
- enzymes
- other products
main areas in which microorganisms are used in biotechnology
-food
- ethanol in beer and wine ( yeast)
- carbon dioxide used to make bread rise ( yeast)
- lactic acid used to make yoghurt and cheese ( lactobacillus bacteria )
main areas in which microorganisms are used in biotechnology
-pharmaceutical drugs
- penicillin ( penicillium fungus)
- other antibiotics ( other fungi or bacteria )
- insulin ( genetically modified bacteria )
main areas in which microorganisms are used in biotechnology
-enzymes
- protease and lipase in washing powders (bacteria)
- pectinase used to extract juice from fruit (aspergillus niger )
- lactase to make lactose free milk ( A. niger and A orzyae