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AS and A Level: Genetics, Evolution & Biodiversity

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  • Marked by Teachers essays 33
  • Peer Reviewed essays 15
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  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
  12. The term GM foods or GMOs (genetically-modified organisms) is most commonly used to refer to crop plants created for human or animal consumption that have been modified in the laboratory to enhance desired traits

    A genetically modified plant is like a superhero compared to natural plants: it can resist to pests and disease, it has the ability to grow in a drought, survive in flood and harsh temperatures, it does not need toxic chemicals to act as pesticides or otherwise aid or protect the plants' growth; and has a nutritious and delicious outcome. These plants with enhanced capabilities are said to be the solution to world hunger because of their incredible efficiency. The importance of efficient plants is becoming a necessity with the increasing population which will require a higher demand in food production; the latter is effectively attainable with genetically modified foods.

    • Word count: 808
  13. I will explain how Deoxyribonucleic acid DNA, stores all of our genetic information and the processes of transcription and translation which expressed genetic information.

    [1] This four sequence of DNA have big role in living organisms, the main function of nucleic acids is to store and transmit genetic information and use that information to direct the synthesis of new protein. Human DNA is nearly a meter in length whereas viral DNA is 1.7mm. DNA is the molecule which controls the synthesis of proteins. Proteins are used for growth and repair and also as enzymes, in which form they catalyse all other cellular activities. There are several kind of RNA and each of them have there own role during the biosynthesis of protein.

    • Word count: 817
  14. Succession and Energy in the Food Chain.

    There maybe many different organisms in the secondary consumer level. Food chains usually have fewer than 5 trophic levels. This is because every transfer of energy (food) up the chain results in a great loss in biomass. This is because food is not eaten and food is not digested. Energy is lost by animals as result of radiation/sweat, respiration, excretion (urine and faeces) and egestion. This energy never reaches the next member of the chain. There is an increased efficiency in supplying green plants as human food. This is because plants only lose 50% of their energy to environment whereas herbivores lose about 80%.

    • Word count: 968
  15. Can snails become habituated to a stimulus

    Firmly touch the snail between the eye stalks with the dampened cotton wool bud and immediately start the stopwatch. Measure the length of time between the touch and the snail being fully emerged from its shell once again, with its eye stalks fully extended. 4. Repeat the procedure in step 3 for a total of ten touches, timing how long the snail takes to re-emerge each time. 5. Record your results in a suitable table. 6. Present your results in an appropriate graph. Safety procedure Wear goggles and gloves at all times during the experiment. Make sure hands are washed after the experiment even if gloves have been worn.

    • Word count: 958
  16. The Human Genome Project

    They are preparing to do this by pinpointing the DNA sequence of an abnormal gene in which a disease originates and associating it with the data of a healthy gene. This research project in its entirety is called "The Human Genome Project." In the U.S., the Department of Energy (DOE) at first, and then the National Institutes of Health (NIH) were the research agencies within the government that were responsible for developing the project. In 1988 the two agencies started working together, this association was formalized by the signing of a Memorandum of Understanding to "coordinate research and technical activities related to the human genome" (National Human Genome Research Institute).

    • Word count: 857
  17. Genetic Mutations

    Most mutations are recognized as 'foreign' by the organism's immune system and are subsequently destroyed. As somatic cells do not produce gametes the mutation is not passed along to the next generation by sexual means. 'Carcinogens' are substances that cause cancerous cell growth which affect the DNA in cells, resulting in mutations. For example, an individual that spends prolonged periods of time under 'ultra violet' light may develop a mutation in a somatic skin cell, and thus develop melanoma. Melanoma develops from melanocytes|. In melanoma the melanocytes start to grow and divide more quickly than usual and start to spread into the surrounding surface layers of skin.

    • Word count: 603
  18. Core practicalWhy do they put mint in toothpaste? Would garlic be better?)

    * Pestle and mortar * 10 cm3 industrial methylated spirits * pipette(sterile) * paper discs * sterile Petri dish * sterile forceps * tape * marker pen * incubator set at 25oC Procedure:- * Cleaned the table with antibacterial spray. * Labelled the Petri dishes for garlic, mint and water (control). * Place agar plate in to a Petri dish and leave it for 5 minutes to allow it to thicken and add bacteria. * Add methanol to both garlic and mint. * Crush the garlic and mint separately * Placed disc one in water, one in garlic and one in mint and tap the dish * Repeated the above steps for two more Petri dishes and add different bacteria to each dish.

    • Word count: 552
  19. Risk Factors of CHD

    Partially due to similar lifestyles of family members but there is evidence for genetic causes. Smoking can significantly increase the risk of death from CHD. Nicotine can make arteries constrict, causing an increase in high blood pressure.

    • Word count: 300
  20. dna extraction from peas

    For example, our DNA controls hair colour and eye colour. In this experiment DNA was extracted from peas. This is an ideal product to use as it doesn't smell (like onions) and also prevents the spread of any disease (e.g., by using animal tissue that may have been infected with BSE or VCJD) and mainly because the method behind it is very simple. Hypothesis It is to be expected that it will be possible to extract DNA from a pea.

    • Word count: 860
  21. Stem Cell Research

    James Thomson and his research team at the University of Wisconsin cultured human embryonic stem cells from spare embryos which had been donated from IVF with consent from the couples. The umbilical chord carries a large source of pluripotent cells. If the blood from the umbilical chord and placenta was frozen and stored then those stem cells would be available throughout the child's life to help them or their family if they needed treatment. However it costs a lot of money to store the blood and also a lot of storage is needed too.

    • Word count: 931
  22. Summarize the aspects of Mendel(TM)s work that suggests his results stood a good chance of being accurate and valid.

    Afterwards, the ripened ovary wall becomes the fruit which in this case, is the pea pod. Most flowers allow cross - pollination, which can be difficult to deal with in genetic studies if the male parent plant is not known. Since pea plants are self pollinators, the genetics of the parent could be more easily understood. Peas are also self compatible which allows self fertilized embryos to develop as readily as out fertilized embryos. Mendel tested all 34 varieties of peas available to him through seed dealers, and the garden peas were planted and studied for eight whole years.

    • Word count: 911
  23. The history of the miscroscope

    At the same time, Nehemiah Grew published his work on tissues. He believed that a woven mass of fibres was what made up living material. It wasn't till the 1840's that cells were recognised as the basic units of life. This was expressed by Matthias Schleiden and Theodore Schwann in their work, Cell Theory, which was published in 1839. Cell Theory was the conclusion that all plants were made up of cells and the same could be said about the organisation of animals.

    • Word count: 520
  24. The human genome project notes

    � The human genome project did not only attempt to sequence human DNA but also the DNA of other organisms. � In 1996, the bases sequence for yeast was published with the sequence for a nematode worm following 2 years later. � In 1999, the first complete chromosome, chromosome 22, was successfully sequenced. � There are over 3 billion chemical base pairs that make up the human DNA, and there are approximately 30-40,000 genes. � 2 years later in 2001, the complete sequencing for a human genome was announced.

    • Word count: 857
  25. Genetic Engeneering in Humans

    Testing has already begun on genetically engineered mice to fight Epidermolysis bullosa simplex which affects a number of children lacking in the protein keratin, after four days of treatment 85% of the mice were free from blistered skin, other diseases like this could be treated by using genetically engineered animals. (5) Another way in which genetic engineering could help people's quality of life is by therapeutic cloning which allows the growth of human tissue which could be used for transplantation without the need for an embryo stage - removing previous moral and ethical objections.

    • Word count: 952

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