HOTS (APPLICATIONS+ DISEASES) BY RV BY RV 2023
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HOTS CHAPTER 3 BY RV 2023
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BY RV 2023
BY RV 2023
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HOTS CHAPTER 4 BY RV 2023
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A polypeptide is a string or linear chain of amino acids BY RV 2023linked together.
HOTS CHAPTER 5 BY RV 2023
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BY RV 2023 Tenderises meat
biodetergent Lipase, cellulose BY RV 2023 Separates the fish skin Extracts fur
BY RV 2023 lactase
HOTS CHAPTER 6 BY RV 2023
The effects of uncontrolled mitosis • When a cell divides by mitosis repeatedly, without control and regulation, it can produce cancer cells. • Cancer is a disease caused by uncontrolled mitosis due to severe disruption to the mechanism that controls the cell cycle. • Cancer cells divide freely and uncontrollably without heeding the cell cycle control system. • Cancer cells compete with the surrounding normal cells to obtain sufficient nutrients and energy for their own growth. • A cancer cell that is not destroyed will divide uncontrollably to form a tumour, an abnormal mass of cellsBY RV 2023
BY RV 2023
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• Cancer cells can intrude on and spread to other tissues which then lead to the malfunction of the tissues and ultimately death. • Cancer can be caused by many factors such as ✓ damage to the DNA ✓ changes in genes (mutation) that control cell division ✓ ionising radiation, for example, X-rays, ultraviolet rays and gamma rays ✓ certain chemical compounds like tar in tobacco smoke ✓ carcinogenic compounds (cancer causing compounds) such as formal-dehyde BY RV 2023
The differences between normal cells and cancer cells BY RV 2023
The application of knowledge of mitosis in cloning The knowledge of mitosis is applied in cloning and the tissue culture technique. BY RV 2023
Cloning 1. Cloning is the process of producing clones or genetically identical copies of a cell, tissue or an organism through asexual reproduction. 2. Animal cloning involves the transfer of the nucleus from a somatic cell to an ovum or embryonic cell with the nucleus removed [somatic cell nucleus to nucleus removed ovum] 3. Many animals have been successfully cloned ever since the first mammal, a sheep named Dolly, was cloned in 1996. BY RV 2023
Cloning 4. Cloning is a form of asexual reproduction because the organisms produced have the same genetic content and chromosomal number as the parent organism. This is a common characteristic of asexual reproduction. 5. The nucleus that directs the development of the offspring comes from a diploid cell produced through mitotic cell division and not through the fusion of gametes produced by meiotic cell division 6. The successful cloning of Dolly has demonstrated that under the right conditions, inactive genes of specialised adult cells can be expressed and made functionalBY RV 2023 once again
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Tissue culture technique 1. Many types of plant and animal cells can be extracted from organisms and cultured in a nutrient medium outside the organisms. 2. Tissue culture technique involves the growth of cells or tissues outside the organisms in a suitable culture medium, which contains nutrients and growth hormones (in vitro methods). 3. In vitro literally means 'in glasses'. The term refers to experiments conducted outside the body of an organism, namely in test tubes or conical flasks. BY RV 2023
4. The main purpose of tissue culture is to produce plant and animal cells through asexual reproduction. 5. Each cell has the full genetic potential (just like a zygote) to form all parts of a mature organism. This means a single plant cell can develop to become a complete plant. 6. Different parts of plants that can be cultured include young shoots, meristematic tissues, leaves, roots, seeds, embryos, cells and protoplasm. 7. In Malaysia, the tissue culture technique is used to propagate plants such as oil palm, rubber trees, orchids and tomatoes. BY RV 2023
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3. The explants or protoplasts are sterilised and then placed in a glass container which contains a nutrient solution with a fixed chemical composition. A culture medium or growth medium normally consists of a complex mixture of glucose, amino acids, minerals and other substances required for the growth of the tissues. The culture medium and the apparatus used must be in sterile conditions and free from microorganisms which can contaminate the tissue culture. The pH and temperature of the culture medium also need to be maintained at optimum levels. BY RV 2023
BY RV 2023
8. Through the tissue culture technique: (a) thousands of new young plants or cloned plants with desirable characteristics and traits such as strong resistance towards diseases can be produced from somatic cells taken from the parent plant. (b) thousands of identical young plants, all having the same characteristics and genetic content as the parent plant can be produced. (c) a large number of identical plants can be grown or propagated for commercial purposes. BY RV 2023
9. With the latest developments in genetic engineering, the genes of a plant can be altered and engineered to produce higher yields. 10.These transgenic plants carry a foreign genetic that has been introduced into their genetic constitution so that they possess new and different traits. 11.Transgenic plants have improved food quality. These plants can be propagated through the tissue culture technique. 12.Transgenic crops like wheat, soya bean and cotton which are resistant to herbicides, pests and diseases have been successfully created by biotechnologists. BY RV 2023
Multiply copies of useful genes → E-coli + growth hormone+insulin Control Environmental pollution →oil spillage Vegetative reproduction → X pollinating agents Shorter period →Less supervision Resistant to herbicides, pests and diseases → Bt + cotton plant → GMF food Larger numbers → genetic engineering BY RV 2023
1. Cloning allows biotechnologists to multiply copies of useful genes or clones. • For example, the bacterium Escherichia coli has been genetically manipulated to produce bovine growth hormones. • The clones of these bacteria can synthesise a large amount of the hormone. • The hormone can then be injected into cows to increase the quality of their milk. BY RV 2023
2. Clones can be produced in a shorter time and in larger numbers. (a) In medicine, for example, the Escherichia coli strain can be cloned to produce insulin. (b) Insulin is a hormone that lowers the level of blood sugar by converting excess glucose into glycogen in the liver. (c) Insulin is produced by the pancreas. A lack of insulin can cause diabetes mellitus. (d) People with diabetes mellitus require a constant supply of insulin. (e) In the past, insulin was obtained by extracting it from the pancreas of animals such as cows after they had been slaughtered. BY RV 2023
(f) The insulin is then purified and used in the treatment of diabetes mellitus. (g) The problem with this method is that it is costly and the amount produced cannot meet the demand for insulin. (h) Today, through genetic engineering, the gene that codes the synthesis of human insulin is inserted into the bacteria’s genome. (i) The genetically modified bacteria are then grown on a large scale. (j) The bacteria multiply rapidly by binary fission, and the human gene replicates together with the bacteria’s own genes. BY RV 2023
(k) The bacterial clones or transgenic bacteria that are being produced are identical because each clone contains the gene to synthesise insulin. (l) The bacterial cells are then lysed so that insulin can be extracted. Because bacteria multiply rapidly and can be grown in large numbers, insulin can be produced on a large scale for commercial purposes. (m)Insulin produced in this way can be made in large quantities, is less expensive and more readily available. BY RV 2023
BY RV 2023
3 (a)Plants that reproduce from seeds take a long time to grow and produce fruits. Cloned plants, however, can produce flowers and fruits within a shorter period. (b)Furthermore, as clones reach maturity in a shorter period of time, less time and effort are needed to properly supervise them in the earlier stages. BY RV 2023
4. Many transgenic crops like wheat, soya bean and cotton which are resistant to herbicides, pests and diseases have been created. (a)Plants are also engineered to produce better quality yields. For example, a gene from the bacterium Bacillus thuringiensis (Bt) is transferred to the cotton plant to create a new transgenic cotton plant which is resistant to the Bt larvae. This gene codes the synthesis of the Bt protein which kills the larvae that feed on cotton plants. BY RV 2023