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AS and A Level: Genetics, Evolution & Biodiversity

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  • Marked by Teachers essays 33
  • Peer Reviewed essays 15
  1. Marked by a teacher

    Too Much Information: Genetic Testing

    5 star(s)

    Some examples of these genetic conditions include Tay-Sach's disease, Bloom syndrome, Deafness, cystic fibrosis, and many other diseases (http://www.einstein.edu/e3front.dll?durki=7158). Although many of these conditions are fatal, the ones that are not can be treated early, even before symptoms develop when possible, or if not treated, at least monitored because of the person's high risk of becoming afflicted. If genetic testing is 95 per cent accurate, which is a reasonable margin of error by any standard, then one in twenty people who take the test will get a false result.

    • Word count: 938
  2. Marked by a teacher

    Compare the Similarities and Differences between Meiosis and Mitosis

    4 star(s)

    These daughter cells are clones to the parent cell. On the other hand, meiosis provides gametes that contain only half the number of chromosome number of an adult cell so that when gametes fuse together in fertilisation, a diploid zygote is formed. Genetic materials in daughter cells of meiosis are slightly different to adult cell due to variation from independent assortment and crossing-over of material. Overview of different phases: Both mitosis and meiosis consists of four main phases: prophase, metaphase, anaphase & telophase.

    • Word count: 629
  3. Marked by a teacher

    Daphnia Write-Up

    3 star(s)

    We set up the different concentrations of caffeine. 0%, 0.125%, 0.25% and 0.5%. We couldn't use tap water, only distilled water, as tap water contains chlorine which can harm the daphnia. So 0% contained no caffeine, only distilled water. 3. We took two glass slides, and put a drop of chilled water in between them: this was so that the heat of the microscopes bulb did not harm the daphnia. 4. We captured a daphnia from the main tank which contained many; we tried to select the largest one possible.

    • Word count: 775
  4. Marked by a teacher

    Thalassaemia is an inherited disease that is caused when there are mutations or a missing gene that affects how haemoglobin is produced. Haemoglobin is the protein in red blood cells that carries oxygen around the body.

    3 star(s)

    or major (b) Alpha To make enough alpha globin protein chains, you inherit two genes (one from each parent). Alpha Thalassaemia occurs when one or more of these genes are missing or have been mutated, the severity of the disease depends on how many of the genes are missing/mutated. * if one gene is affected you are likely to have no or little symptoms and are known as a silent carrier * If two genes are affected this means that you will have alpha thalassaemia trait and are therefore known as a carrier. you will also experience mild anaemia * If you have three genes affected, you will have moderate to severe anaemia, also known as haemoglobin H disease.

    • Word count: 725
  5. Marked by a teacher

    How light intensity affects biodiversity

    3 star(s)

    inside the area I am using. Method : I used a quadrat, a light meter and a string with markings every 1 1/2 m. I decided on a level that I would take all my results from which had a range of different intensity's of light and decided on a point to start where I would get a decent number of results. From there I laid out the string to make it easier to keep the results equal distances apart, (1/2 m apart.)

    • Word count: 902
  6. Marked by a teacher

    Focus on genetic fingerprinting

    3 star(s)

    These enzymes recognise specific sequences in the DNA. Because each of us has a unique sequence of nucleotides in our DNA, the lengths of these bits will vary from per4osn to person. Electrophoresis is then used to separate out these bits according to their size and charge. The net result is a pattern unique to each of us. [image002.jpg] How this can be use? Well, basically this technique is mostly used by police. In the cases like murderers, rapists, burglars and muggers, this technique can help to track down then from traces of blood or other body fluids left behind at the scenes of their crimes.

    • Word count: 910
  7. Marked by a teacher

    The Human Genome Project (arguments for and against)

    3 star(s)

    For example, if a person had cystic fibrosis, doctors could located the mutant gene responsible for this disease, change it to make it "normal" and then the person who has this mutant gene would survive and live a healthier life. Now that the odd gene has been changed, the children of that patient would have no risk of being passed on with cystic fibrosis. Although this sounds like a great idea, to cure people of horrific hereditary diseases, some individuals believe that it is wrong to alter the course of nature and create a "perfect race".

    • Word count: 635
  8. Peer reviewed

    Cystic Fibrosis

    4 star(s)

    The CFTR gene is responsible for producing the CFTR protein, which allows Cl- ions to diffuse out of cells in water regulation. If the gene in the DNA is mutated, the mRNA produced in transcription will code for the wrong sequence of amino acids, so the protein made by the mRNA in translation will be the wrong shape, and therefore will not function correctly. This diagram shows the normal situation, where there is too much water in the mucus (outside the apical end of the cell).

    • Word count: 717
  9. Peer reviewed

    The ethical and social implications of genetic screening

    4 star(s)

    Already we take for granted pre-natal screening, in which genes are analysed from a sample of anionic fluid, and in many cases foetuses with abnormal genes are aborted. Could knowledge of more genes, and therefore increasing the likelihood of spotting a faulty or abnormal gene, lead to an increase in abortion rate? Of course, some people believe the terminations would be justified. Maybe the termination would be better for the parties involved. It would make life easier for the parents as life would surely be difficult with a disabled child and perhaps, awful it may sound, it may be better for the child.

    • Word count: 978
  10. Peer reviewed

    Discuss the Moral and Ethical issues of Cloning Animals

    3 star(s)

    As animals are living organisms, it is therefore wrong to manipulate with their cells and killing the cell after the experiment is equivalent to killing an animal. The experiment might also be regarded as torture to animals, as we add in chemicals in Petri dishes to stimulate growth of cells. However, some people would agree with the act of cloning, as this is for the greater good. The result of animal cloning could lead to the evolution of reproductive and therapeutic cloning, and eventually could clone an entire organ for cure of diseases, e.g.

    • Word count: 612
  11. Peer reviewed

    recombinant DNA

    3 star(s)

    (reference:http://en.wikipedia.org/wiki/Recombinant_DNA , info taken on 25 january 2008. this site gives a general description on recombinant dna and its founders also some of the uses of recombinant dna) Uses of RDNA: Genetically engineered micro organisms-human organisms are inserted into bacteria which are grown into fermenters , the bacteria produce proteins, also large amount of insulin is produced cheply this way. ( reference: 'AS AQA BIOLOGY specification A','A new introduction to BIOLOGY,'Page 164). Genetcally modified plants- transgenic genes are inserted inside plants so they become immune to hebicides and pestisides .

    • Word count: 964

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