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2.2.1 Clones in Nature
· Clone: Genes, cells or whole organisms that carry identical genetic material because they are derived from the same original
· Identical twins are natural clones they are produced when a zygote splits in two.
· Asexual reproduction = mitosis = genetic material replicates + separates to form 2 new nuclei each containing an exact copy
of the original DNA.
Advantages of Asexual Reproduction
· It is QUICK allows organisms to reproduce rapidly + take advantage of the resources in the environment.
· It can be completed if SEXUAL reproduction fails/is not possible.
· All offspring have the genetic information to enable them to SURVIVE in their environment.
Disadvantages of Asexual Reproduction
· Does not produce any genetic VARIETY so any genetic parental weakness will be in all the offspring.
· Vegetative propagation is the production of structures in an organism that can grow into new individual organisms these
new organisms are clones of the parents.
· This allows the species to survive catastrophes like disease.
· Basal sprouts appear within 2 months of the destruction of the main trunk they grow from meristem tissue in the trunk
close to the ground.…read more
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2.2.2 Artificial Clones + Agriculture
· 2 main methods of artificially propagating valuable plants:
TAKING CUTTINGS: a section of stem is cut and is treated with plant hormones to encourage root growth and is then planted. A new plant is
formed that is a clone of the original parent plant.
GRAFTING: a shoot section of a woody plant is joined to an already growing root + stem. The graft grows and is genetically identical to the
parent plant but the rootstock is genetically different.
Artificial Propagation using Tissue Culture: Large-Scale Cloning
· Cuttings and Grafts cannot produce huge numbers of cloned plants very easily + some plants do not reproduce well from
· More modern methods use tissue culture in order to generate huge numbers of genetically identical plants from a small
amount of plant material.
· Tissue culture is the separation of cells of any tissue type and their growth in/on a nutrient medium.
1. A small piece of tissue is taken from the desired plant, usually from the shoot tip, called the explant.
2. The explant is placed on a nutrient growth medium.
3. Cells in the tissue divide + form a mass of undifferentiated cells called a callus.
4. After a few weeks, single callus cells can be removed from the mass + placed on a growth medium containing plant hormones to encourage
5. After another few weeks, the growing shoots are transferred onto a different growing medium containing plant hormones to encourage root
6. The growing plants are then transferred to a greenhouse to be acclimatised + grown further before they are planted outside.
Advantages of using Callus Culture
· Farmers know what the plant produced will be like because it is a clone of the original plant.
· Farmers' costs are reduced because all the crop is ready for harvest the same time.
· Much faster than selective breeding because lots of plants can be produced from a small number of plants.…read more
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2.2.3 Cloning Animals
· There are 2 methods of artificially cloning animals:
SPLITTING EMBRYOS [ARTIFICIAL IDENTICAL TWINS] = cells from a developing embryo can be separated out where each one goes on to
produce a separate, genetically identical organism.
NUCLEAR TRANSFER [USING ENUCLEATED EGGS] = a differentiated cell from an adult can be taken + its nucleus is places in an egg cell
without its own nucleus (enucleated). The egg then develops with the genetic material from the inserted nucleus.
Advantages of Cloning Animals
· High-value animals can be cloned in large numbers.
· Rare animals can be cloned to preserve the species.
· Genetically modified animals can be quickly reproduced.
Disadvantages of Cloning Animals
· High-value animals are not necessarily produced with animal welfare in mind.
· Excessive genetic uniformity in a species makes it unlikely to be able to cope with/adapt to changes in the environment.
· It is unclear whether animals cloned using the nuclear material will remain healthy in the long term.
What is Non-Reproductive Cloning?
· Possible in the future to use cloned cells to generate cells, tissues + organs to replace those damaged by diseases/accidents.
· Advantages of using cloned cells:
Being genetically identical to the individual's own cells so they wont be rejected by the immune system.
Could end the current problems of waiting for donor organs to become available.
Cloned cells can be used to generate any cell type because they are totipotent.
Less dangerous then major operations.
· There are many possibilities for non-reproductive cloning:
Regeneration of heart muscle cells following a heart attack.
Repair of nervous tissue destroyed by diseases like multiple sclerosis.
Repair of the spinal cord of those paralysed by an accident.…read more
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2.2.4 Biotechnology Basics
· Biotechnology is technology based on biology and involves the exploitation of living organisms or biological animal
husbandry, food science, medicine and industry.
· In recent years, our growing understanding of genetics and ability to manipulate living organisms in a variety of ways has led
to a huge expansion in biotechnological processes.
· Biotechnology has applications in 4 major areas that affect our lives:
HEALTHCARE + MEDICAL PROCESSES: includes the production of drugs by microorganisms + gene therapy to treat some genetic disorders.
AGRICULTURE: includes micropropagation of plants + the development of genetically modified plants.
INDUSTRY: includes genetically modifying organisms to produce enzymes.
FOOD SCIENCE: includes developing foods with improved nutrition or better taste, texture + appearance.
BLUE BIOTECHNOLOGY: applied to marine and aquatic environments.
The Use of Microorganisms in Biotechnology
· Many biotechnological processes make use of microorganisms because they:
Grow rapidly in favourable conditions.
Often produce proteins/chemicals that are given into the surrounding medium and can be harvested.
Can be genetically engineered to produce specific products.
Grow well at low temperatures.
Can be grown anywhere in the world not dependent on climate.
Can be grown using nutrient materials that would be otherwise useless/toxic.…read more