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AS and A Level: Genetics, Evolution & Biodiversity

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  1. Gene mutations

    Types of gene mutation There are a variety of forms of gene mutation involving the addition, loss or rearrangement of bases in the gene. These mutations take the form of the duplication, insertion, deletion, inversion or substitution of bases. In all cases they change the nucleotide sequence and result in the formation of a modified polypeptide. For example, deletion causes a frame-shift. Consequences of gene mutations Gene mutations occurring during gamete formation are transmitted to all the cells of the offspring and may be significant for the future of the species.

    • Word count: 634
  2. ‘The use of recombinant DNA technology can only benefit humans’

    Not only humans but also plants, sea creatures and insects. With any technical advances new public policy needs arise. Recombinant DNA is an example of a technology that has created a large degree of debate in the public arena. Many people will agree and many will disagree so getting evidential advantages is a must. This debate is: * Emotional (ethical views of people, e.g. religious beliefs)

    • Word count: 532
  3. Recombinant DNA: its functions and moral differences

    Recombinant DNA technology essentially alters the characteristics of an organism by changing its protein makeup. Recombinant DNA techniques have transformed genetic engineering in plants and animal food production, industry and medicine. In most cases, DNA cannot be transferred directly from its original organism (donor) to the recipient organism (host). Instead the donor DNA must be cut and recombined with a matching fragment of DNA from a vector that is, an organism that can carry the donor DNA into the host.

    • Word count: 709
  4. The use of Recombinant DNA Technology can only Benefit Humans

    In 1982, genetically engineered insulin was approved for use by diabetics. To provide a reliable source of human insulin, researchers obtained from the human cells of DNA carrying the gene with information for making human insulin. Researchers made a copy of DNA carrying this insulin gene and moved it into a bacterium. When the bacterium was grown in the lab, the microbe split from one cell into two cells, and both cells got a copy of the insulin gene. Some human diseases are caused by a defective gene. An example is cystic fibrosis, a disease of mucous glands throughout the body that usually develops during childhood and makes breathing increasingly difficult.

    • Word count: 819
  5. Sex Determination in mammals

    This in turn facilitates the continuation of outbreeding necessary for natural selection. Genetic sex The beginning of determination is from the inheritance of an X or Y chromosome from the father. If a Y chromosome is inherited then the progeny will be phenotypically male (XY), conversely, if an X chromosome is inherited the progeny will be phenotypically female (XX). These chromosomes contain the vital genetic information required for organogenesis of the sex organs. The genes involved can be seen below...

    • Word count: 789
  6. Genetic engineering can be used to solve many problems in the world, but some people feel that the dangers out weigh the advantages. Discuss the use to genetic engineering today and the moral, ethical and economic implications of the technique.

    This technique has been used but only with limited success. With more research into this area is could be used more widespread to treat genetic diseases. Both animals and bacteria can be modified to produce substances that can be used to help treat those people who cannot produce the substance naturally themselves. You can make transgenic organisms by inserting a gene from one organism into another to make it produce a new substance. Bacteria can be modified to produce insulin.

    • Word count: 892
  7. Human Cloning - argument

    Also, because there are many benefits to cloning and since not everyone believes in a god why should religion be used in making decisions for people where religious morality is not even an issue? The beliefs of some people should not stop others from the benefits of cloning. There are those with religious beliefs who think that taking antibiotics or receiving blood transfusions is wrong, but this does not stop the rest of the world from receiving the benefits from them.

    • Word count: 889
  8. A Murder Mystery

    He raised the alarm and the police were called in. Detective chief inspector wellings was called in to head up the murder inquiry. The area was sealed off and a scene of crime officer scoured the area for clues. The doctor confirmed that the body had been stabbed with a 6-inch blade knife through the heart. The search for the weapon began and DCI Wellings had a team of officers combing the local area for any clues. On examining the body the doctor found traces of fibre and different colour hair than that of the victim.

    • Word count: 672
  9. Polymerase Chain Reaction

    The solution is then mixed with DNA polymerase, and nucleotides. Some short nucleotide sequences which act as a "start" signal for replication (primers) are also added to the solution. The temperature of the solution is slowly lowered to 53?c, to allow primers to bind to DNA. The temperature is then raised again to 73?c to enable thermostable polymerase to replicate DNA. This cycle of temperature changes is repeated about 20 times. Gene amplification begins with double-stranded DNA. Denaturing - This DNA is then heated, making the strands separate.

    • Word count: 651
  10. Genetic Engineering – Friend or Foe?

    At the end of this essay there will be a conclusion to my essay and my personal views on Genetic Engineering. What are the benefit and the effect of Genetic Engineering? Genetic Engineering increase plant and animal productivity to supply food for us but it will almost certainly endanger species and reduce biological diversity. Genetic engineering in food could lead to the increase in the use of chemicals in agriculture and further contamination of the environment. Some people might think that this is a good way of making good product in which they select the best plant/animal and using it genes to make the same one but what about those people who are allergic to a certain type of food?

    • Word count: 990
  11. Recombinant DNA technology used for insulin production

    The process which is to be followed is named as ?Recombinant DNA Technology?. In order to access the gene that is responsible for the production of insulin in humans, the DNA it is found on, must be extracted from the human cell. This is primarily done by breaking the cell membrane and then the nuclear membrane of the human cell, allowing having direct access to the chromosomes which will actually lead onto identifying the exact location (Gene Mapping) of the human insulin gene on the chromosome.

    • Word count: 773
  12. DNA Fingerprinting process

    containing the insulin gene are being reinserted into the E.coli cells, there is a very low possibility that all the plasmids will be able to make it to the desired location (E.coli cells). How is PCR Done? PCR is a 3 stage cycle; 1. The first stage is the Denaturing of DNA which is carried out at 94-96°C. At this stage, the high temperature breaks up the hydrogen bonds which hold the double stranded DNA together and the strands separate into two single strands.

    • Word count: 969
  13. Sex linkage in fruit flies and huntingdons disease

    It is known that red eye colour (R) is dominant to white eye colour (r). In the P generation red eyed male flies (XRY-) were crossed with white eyed females (XrXr). The outcome of the F1 generation were half male white eyed (XrY-) and half female red eyed (XRXr). These results were obtained because the mothers? genes determine the male offspring?s eye colour; as the mother has both recessive, white eye colour alleles, the male offspring?s are 100% white eyed (XrY-).

    • Word count: 761
  14. Genetics- Transcription and Translation

    It helps the single RNA nucleotides to match up with the nucleotides on the template DNA strand. This process occurs through complementary base pairing, when Adenine matches Uracil, Thymine with Adenine, Guanine with Cytosine and Cytosine with Guanine. The template strand is complementary to the coding strand and due to this reason the RNA strand is built by using the template strand. This way the exact copy of the coding strand is formed on the mRNA strand, the only difference is Uracil takes the place of Thymine.

    • Word count: 893
  15. Mitosis in Onion Tip cells and Meiosis in Locust Testis Squash Cells

    The spindle fibres hold on to the centromere of the chromosome to accomplish the task of aligning them. In Anaphase the centromeres separate and the spindle fibres shorten in order to pull the sister chromatids to the opposite poles of the cell. Now, there are 46 haploid chromosomes on each pole of the cell. The chromosomes are still in the shape of fat fingers. During Telophase, the spindle fibres break down and disappear, allowing the nuclear membrane to re-appear around the two sets of 46 haploid chromosomes on opposite poles of the cell. The nucleolus also reforms. The chromosomes become uncoiled (spaghetti-like).

    • Word count: 887
  16. Conservation in Zoos & Seedbanks Revision Notes

    some individuals can be released into the wild or protected areas such as national parks, to maintain or re-establish wild breeding populations * The genetic diversity of the species is maintained * Reintroduction programmes: these programmes endeavour to release captive bred individuals back into the wild so that natural breeding populations can be maintained or re-established Importance of maintaining genetic diversity during captive breeding programmes: * The problem is that some zoos can only have a small number of individuals, so inbreeding is likely to occur.

    • Word count: 508
  17. M2. Discuss the impact on individuals and society of genotypes resulting in developmental delay or impairment of normal body functioning

    Translocation DS- where some of or the entire third 21st chromosome is trans-located to another chromosome, usually the chromosome 14. This only occurs in about 3-5% of the Downs Syndrome population. Down?s syndrome is a life- long condition which develops whilst the baby is in the womb; affecting the individual?s normal physical development and causes moderate to severe learning difficulties. This is due to the fact that Downs syndrome causes the brain cells to deteriorate faster than a normal persons.

    • Word count: 804
  18. In this essay the researcher will discuss the impact of Multiple Sclerosis and how it affects the immune system

    Multiple Sclerosis can affect both males and females and usually starts between the ages of 20-50 years old. Multiple Sclerosis is believed to be the cause of damage to the myelin sheath which protects each nerve fiber disrupting the transfer of impulses from the brain to the body. There are four types of MS which are, Relapsing-Remitting MS which is clearly defined attacks followed by complete or partial recovery, Secondary-progressive MS which occurs 10-20 years

    • Word count: 700
  19. With the aid of specific examples, describe the concept of a hierarchy of biological organization. What is meant by the phrase the whole is greater than the sum of its parts?

    The hierarchy of biological organization is a group of different systems that sustain life through emergent properties. The first four levels of this organized group are the biosphere, ecosystem, community, and population. The biosphere contains all the living and nonliving matter here on earth. The nonliving matters, such as sunlight, wind, and bodies of water and land have a direct effect on the living matter contained in the biosphere. The second level is the ecosystem which at various locations, contain all living organisms and nonliving matter in one place.

    • Word count: 872
  20. Cystic Fibrosis

    Steroids can be taken to help reduce the swelling in the lungs. DNase can also be taken which thins out the mucus found in the lungs making it easier to be coughed up. A type of treatment used to help the digestive system is a supplement of vitamins A, D, E and K these are taken along with a well balanced diet which is low in fat and high in calories, proteins and pancreatic enzymes. A new therapy that has been introduced is gene therapy.

    • Word count: 808

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