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AS and A Level: Genetics, Evolution & Biodiversity

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  1. Mutation and its Consequences - Gene mutations occur when there is change in the sequence of bases, such as when the gene is copied incorrectly.

    If one base were to be substituted, the DNA sequence would then read: AGC TAC GTA AGT. The last codon will now be transcribed as UCA which translates into the amino acid Serine. Because the primary structure has now been changed, this may affect the tertiary and quaternary structures. > Addition o Addition occurs when an extra base is added into the sequence. All the bases that follow are also moved along. This is called a frame shift. Original base sequence AGC TAC GTA CGT Becomes: AGC ATA CGT ACG T... The codons that come after the addition will now be affected and most amino acids will be changed into another amino acid.

    • Word count: 637
  2. Crop and Animal Biotechnology - Ethics and Morality.

    This organism is transgenic, meaning its DNA has been altered. There are numerous useful functions of genetic engineering. Use of biotechnology means that smaller quantities of crops would be lost, as plants could be altered to be pest and disease resistant. It can make crops more nutritional, and it can also make the crops last longer. An advantage of cloning is that it will be possible to clone organs for transplants, meaning people will not have to wait for donors.

    • Word count: 457
  3. Discuss a recent article you have read in a magazine or a journal related to an aspect of health education.

    The whole controversy over genetic engineering is not just medical but social, political and moral. Once where doctors were not permitted to identify the gender of a baby is now not the case. Parents can now know the gender of a human embryo. This is causing population differences when it comes to gender in countries such as India and China. The ratio of males is higher than females in these countries because parents are choosing to abort the foetus when they find out it is female. Genetic engineering is also being used to create babies from generative diseases. Such as the couple in America who wanted a baby free from the genetic disease Tay sachs.

    • Word count: 698
  4. Critically consider evolutionary explanations for human intelligence.

    Evolutionary explanations for intelligence fall into two categories - the ecological explanation and the social explanation. The ecological explanation looks at and measures intelligence in terms of ability to find and obtain food, using tools and hunting. Animals with more advanced cognitive maps (i.e. those with better memories for where food can be found or is stored) will do better and be more likely to survive than those animals with less advanced cognitive maps, and therefore the lesser cognitive maps will be selected out. Humans have large brains for their bodies, and this must be of some evolutionary advantage.

    • Word count: 666
  5. The common statement that people put across when debating over the moralities of human cloning is that it is unnatural.

    This nucleus can be from either a male or female source. The insertion of this nucleus creates what is known as a 'Clonal Zygote.' This zygote undergoes mitosis and creates the 'Clonal Embryo.' When the baby develops, you must ask yourself what relationship the baby has with its donors. The baby is not a brother, sister, son or daughter but a new form of biological relationship which can only be described as a clone. This subject, I find, is quite chilling. 'There are millions of human clones walking the face of the earth. We call them identical twins.' (Dr. Lee Silver, REMAKING EDEN: CLONING AND BEYOND IN A BRAVE NEW WORLD)

    • Word count: 927
  6. Inducible Operon VS Repressible Operon - Genetic regulation is a process where certain proteins and other kinds of stimuli tend to cause a cell to express genes or not express them.

    Structural genes code for the enzymes themselves. RNA polymerase transcribes all of the genes into a polycistronic mRNA. The promoter is the site where the RNA polymerase binds to the DNA prior to beginning transcription. The operator serves as the binding site for the protein called the repressor. The regulatory gene encodes the repressor protein. An inducible operon is an operon in which the presence of a key metabolic substance induces transcription of the structural genes. One example of an inducible operon is lac operon and the inducer of this operon is lactose.

    • Word count: 628
  7. The arguments for and against genetically modified foods

    foods. The main issue with GM foods is that it is unnatural and said to be playing "God". Many biotechnology companies persistently claim that their methods of genetic modifications are similar to natural genetic changes, or more commonly and traditionally used techniques such as cross breeding. However, some of the modifications involve using genes from one species and inserting it into another. The cross species transfer often involves unrelated species such as between insects and tomatoes or fish and lettuce. This type of cross breeding would not occur in nature and could lead to many new toxins, diseases and weaknesses.

    • Word count: 859
  8. 'Only God has the right to interfere with our genes' Do you agree? Give reasons for your opinion showing you have considered another point of view. In your own answer you should refer to religious teachings.

    Many religions may argue that only God has the right to interfere with our genes and that it is wrong for scientists to be in control of life rather than God. Religions may also argue that by scientists interferring with life they could get rid of certain genetic features which the parents are not particulary fond of, which could be like the creation of a master race. It would also mean that whilst cloning, only ceratin embryos should survive so the others would get discarded and many Hindus would argue that this is going against their Ahimsa (the belief of non-violence).

    • Word count: 834
  9. Cloning, is it man playing god?

    Cloning is not playing of god, rather it is a salutary act which can fulfill human needs. There are three different types for cloning: Embryo cloning, adult DNA cloning and therapeutic cloning. Embryo cloning is a medical technique which produces monozygotic twins or triplets. Adult DNA cloning is a technique which is intended to produce a duplicate of an existing animal and therapeutic cloning is a procedure that starts off like adult DNA cloning. Generally, when people hear the term 'cloning', the first thing come to their mind is the creation of human monsters or armies of superhuman soldiers.

    • Word count: 686
  10. Cloning is the process of asexually producing a group of independent organisms or cells, all genetically identical, from a single ancestor.

    have a baby exactly the way they want it and to be able to determine its gender, would be an even greater opportunity. Also in vitro fertilization is not always successful. If cloning could prove 100% a success then a lot of infertile couples would be able to have children at any age. It certainly would help the medical industry in an even greater number of advantages, as it would improve reconstructive and cosmetic surgery. The surgery could be improved by using real skin and other tissues that will be an exact match for a particular patient.

    • Word count: 987
  11. Meiosis. Before meiosis can happen, the DNA Must replicate, this is done in the stage of interphase. Following interphase the first stage of meiosis occur

    The chromosomes become more visible by coiling up and condensing. In mid prophase I the nucleolus had gone ant the chromosomes, which consist of two identical chromatids, come together in their bivalents. A bivalent is a pair of homologous chromosomes. Next in late prophase I the nuclear envelope disintegrates so the spindle fibres can attach to the centromeres. The chromosomes can now be seen as two chromatids. In this stage adjacent non-sister chromatids can cross over at the point of chiasma and exchange part of their genetic material. The Next stage of Meiosis is metaphase I.

    • Word count: 564
  12. How far can scientific experiments on living creatures be justified?

    This proposed process of evolution has been proven to take quite a long time to occur. Scientific modern day man has found that this evolutionary process is painfully slow and in the last decade has taken the initiative to literally 'speed-up' this process. Man has been able to modify simple organisms so that they will produce proteins for human health purposes. Patients suffering from terminally ill diseases have used these proteins to make their lives easier and less painful. Man has been able to alter the genes of certain crops in order to make them more resistant to certain pests and diseases, resulting in a greater yield.

    • Word count: 696
  13. Biology - science of the future

    This is for safety reasons in case there are unknown side-effects, which could be detrimental to the life of a human being using the product in question. One of the most recent and interesting developments has been Genetic Engineering. Due to a lack of sophisticated equipment and technology in previous years, studying the gene in depth was impossible. A revolution in modern biology occurred in the years 1971 - 1973, which allowed genetic research to make great advances. Today, genetic engineering and gene cloning is allowing for progress in medicine, industry and agriculture.

    • Word count: 947
  14. It has been suggested that the benefits of genetic engineering far outweigh the concerns about its use. Discuss the arguments for and against this statement.

    If this micro-organism turns out to also be a cure for another possibly worse illness, then what will we do? It is possible that by letting genetic engineering play a much larger part in our lives, we are shooting ourselves in the foot. Then again, the amazing advances genetic engineering has allowed to happen, in the production of insulin for sufferers of diabetes, goes to show that, if used in the right way, and carefully, it can do something very good.

    • Word count: 972
  15. Deoxyribonucleic acid

    DNA molecules are exceedingly long polymers and exist as two chains, which come together to form a double helix. The chains are orientated in opposite directions and arranged side by side. With the nitrogen bases forming the cross rungs. The building blocks of nucleic acids are nucleotides. Made up from a carbon sugar, a phosphate group, and an organic nitrogen containing base A pairs with T G pairs with C The DNA in a human cell contains around 3 billion base pairs.

    • Word count: 217
  16. 'Only God has the right to interfere with our Genes'

    There are many Arguments in Favour and Against Genetic engineering, both religious and non-religious. The Non-religious Argument in Favour agrees with me as I say that it offers the chance to cure hereditary or incurable diseases. The other reasons in favour are because it is available in other countries and only people rich enough can afford the treatments and it is a part of medical research, which is closely monitored by the law. The Non-religious Arguments against Genetic Engineering state that it does not give enough information about the consequences and has effects that would be permanent, if anything went wrong.

    • Word count: 647
  17. The Future Impact That the Human Genome

    Deoxyribonucleic acid (DNA) contains all our hereditary material that contains all of our genes. DNA is made up of four chemical bases which are twisted in pairs. HGP researchers are working out the human genome in three major ways: 1) Determining the order of sequence of all the bases in our DNA. 2) Making maps showing the location of genes. 3) Producing linkage maps (Inherit traits can be tracked over generations). The advantages of the HGP are mainly: 1) Diagnosis and Prediction of Disorders All diseases have a genetic component, whether inherited or environmental.

    • Word count: 900
  18. Genetic engineering

    Nowadays, the gene for making chymosin was transferred from cows to yeast because 1) many people consider it is wrong to slaughter calves, 2) chymosin from yeast is cheaper and purer. So today, over 90% of all hard cheese is made from chymosin produced by genetic engineered yeast. Medical application How to attempt to alleviate the symptoms of genetic diseases? The disease I am going to talk about is cystic fibrosis. CF is a bronchial infection, which causes the early death for patients with this genetic disease because the lungs of CF patients produce thick mucus that provides a great growth medium for bacteria and viruses.

    • Word count: 677
  19. The Use of Recombinant DNA Technology Can Only Benefit Humans

    Using procedures like recombinant DNA, many human genes have been cloned in E. coli or in yeast. This was made possible for the first time to produce unlimited amounts of human proteins. Cultured cells (E. coli, yeast, mammalian cells) transformed with the human gene are being used to manufacture: insulin for diabetics, human growth hormone (GH) GH from domestic mammals like cows and pigs does not work in humans. So for many years, the only source of GH for therapy was that taken out from the glands of human cadavers. But this supply was shut off when several patients died from a rare neurological disease attributed to contaminated glands.

    • Word count: 759
  20. The Human Genome Project and its Moral and Ethical Consequences

    With this information they are able to create many medical benefits and improve technology greatly. With gene testing scientists would be able to clarify a diagnosis and direct the appropriate actions towards the patients as well as warning parents that they may have children with diseases and identifying people with high risk of preventable conditions.

    • Word count: 475
  21. Learning about the structure of the CRO Repressorprotein

    Other functions include the transport and storage of protein molecules and also control the growth and differentiation. Cro and Repressor are part of the lysogenic/lytic growth switch mechanism in bacteriophage and function through transcription regulation at operons. DNA binding is conducted as a homodimer. Each monomer interacts with a pseudo-symmetric half-site. Repressor proteins - the monomers have a two-domain structure: * N-terminal domain: a 69 residue DNA-binding domain known as R1-69. It is a 5-helix bundle with helices 2 and 3 forming a helix-turn-helix motif.

    • Word count: 428
  22. Why are researchers and scientists so interested in cloning?

    Although the process used to transfer these genes is very hit and miss. A new more precise way of transferring these genes needs to be found, if the scientists could find a more precise method the they would be able to create some genetically engineered sheep that would then reproduce eventually making a whole flock of genetically engineered animals all producing medicines in they're milk. Scientists are also interested in cloning because of its use in the development of animal organs for transplant into humans (xenotransplantation).

    • Word count: 731
  23. Biological explanation for anorexia nervosa (Holland et al, 1988): Evidence for a faulty gene.

    If there was any doubt, a blood test was done to establish genetic relatedness. * Diagnosis of anorexia was based on standard clinical criteria FINDINGS: * 9 out of 16 (56%) MZ twins were concordant for anorexia * 1 out of 14 (7%) DZ twins were concordant for anorexia * In 3 cases where the second twin did not develop anorexia, they did develop other psychiatric disorders and two suffered from minor eating disorders. CONCLUSIONS: * The findings show that there is a much higher concordance rate for anorexia in MZ twins compared to DZ twins * This suggests provide good evidence for genetic factors causing some cases of anorexia, and possibly other psychiatric disorders.

    • Word count: 909
  24. Chromosomes

    The information they carry has a strong influence over our personal characteristics. Showwhere on the chrormsonme is a very narrow region which is known a s a centromere. This is a picture of the 23 pairs of chromosomes in the human. The chromosomes seem to have a very basic structure how ever this is not the case chromosomes have a very complicated structure.However the same is characterised and the 23 pairs of chromosomes all follow the same simailarties in look only the size and thickenss vary in looks. Chromosomes are long thin structures, .

    • Word count: 804
  25. Genetic Engineering - a laboratory technique used by scientists to change the DNA of living organisms

    Geneticists in addition, believe they can improve the foods we eat. For instance, tomatoes cannot endure the hardship of frost so geneticists identified a particular gene that enables a flounder to resist the cold and genetically inserted the gene into the tomato. This makes it possible to extend the growing season of the tomato. Genetic engineering has generated vaccines and altered livestock traits; it has also produced pharmaceutical compounds and increased the disease resistance of crops. At first glance, this might look exciting to some people but if you take deeper consideration it reveals serious dangers.

    • Word count: 632

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