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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

    Revision notes - origins of life on Earth, chemistry of life

    5 star(s)

    * Life may have evolved in these areas using chemical energy available from vents. Abiogenesis (Urey-Miller) * Life on earth arose from organic molecules existing on the primitive earth (amino acids - basic building blocks of life) Panspermia * Suggests either very primitive organisms or complex organic compounds travelled to earth from space. In each theory, before life could have originate/evolve complex organic compounds first had to be formed. Theories differ in how these precursors formed � shallow oceans (Urey-Miller); formation of chem.

    • Word count: 2113
  2. Marked by a teacher

    The Human Genome Project

    5 star(s)

    This double-helical structure of the DNA molecule was discovered Watson and Crick in 1953, for which they received the Nobel Prize for Chemistry. The bases from each side join in pairs to form the "rungs" of the ladder-specifically, adenine always pairs with thymine, and guanine always pairs with cytosine. The genetic code is specified by the order of adenines, thymines, guanines, and cytosines in the DNA ladder. A particular section of the DNA ladder usually has a unique sequence of base pairs.

    • Word count: 2268
  3. Marked by a teacher

    Biology Issue Report on GM Foods

    4 star(s)

    These two sets of figures do not necessarily tally but the current population is not currently receiving enough food and rising population is not the only factor in food demand. In addition to population growth and reduced rainfall, soil fertility can be depleted by a lack of access to fertiliser and bad farming practices which reduces the area suitable for crops and pasture. Genetic Modification of Crops ? A Biological Solution One solution in combatting food shortages and ensuring healthy yield is ensuring that crops are chosen for planting which are able to grow with a minimal amount of water.

    • Word count: 2177
  4. Marked by a teacher

    Evolution. This issue report will aim to address the Theory of Evolution by explaining key concepts and ideas in an informative and unbiased way. It will set forth to describe the theory, by highlighting its main components,

    4 star(s)

    They are convinced that they can draw definite conclusions about the origins of life. There are other rationally sound models that deny the original Theory, branding it incorrect. However, are biologists justified in stating that the Theory is ultimately flawless and cannot be refuted? They have to convince everyone that their exposition of science is valid. Before they can find a solution to their problem, let's go back to basics. Firstly, what is the definition of biological evolution? "...biological evolution is defined as descent with modification from a common ancestor."

    • Word count: 2081
  5. Marked by a teacher

    The Loss of the Lemur: The Road to Extinction

    4 star(s)

    I undertook a visit to Woburn Safari Park, which keeps this sub-species of lemur, in order to find the answers to these questions and visit the very animals facing extinction half way around the world. The Cause Although the problem of the declining lemur population was identified by 1986, the problems in Madagascar are still highly prevalent and affecting the subspecies greatly. There are two main causes for this decline, highlighted during the visit by Adele Clegg, Head of Learning at Woburn Safari Park.

    • Word count: 2074
  6. Marked by a teacher

    Human Cloning Assignment

    4 star(s)

    Each group of researchers has its own specific technique. The best known is the Roslin technique, and the most effective and most recently developed is the Honolulu technique. The cloning of Dolly has been the most important event in cloning history. Not only did it spark public interest in the subject, but it also proved that the cloning of adult animals could be accomplished. Previously, it was not known if an adult nucleus was still able to produce a completely new animal. Genetic damage and the simple deactivation of genes in cells were both considered possibly irreversible.

    • Word count: 2972
  7. Marked by a teacher

    Should Gene therapy be allowed to prevent cystic fibrosis?

    3 star(s)

    The problem in doing it is integrating the DNA into the genome and the rapidly dividing nature of cells prevents gene therapy from achieving any long term cure. If patients wanted a longer and stable cure, they will have to undergo multiple rounds of gene therapy. * There are problems with viral vector; a study has shown potential problems to the patient, such as inflammatory, toxicity and immune responses. Furthermore if the viral vector starts to recover, there is always a possibility that it could cause disease.

    • Word count: 2948
  8. Marked by a teacher

    Can Germ line Gene Therapy be used as a treatment for Huntingtons Disease?

    3 star(s)

    When a mutation occurs, this protein is no longer produced and instead a different form of protein is produced. This protein initially causes very little harm to the brain, but after a prolonged time, it damages nerve cells in the brain and leads to Huntington's disease. The full process of Huntington's disease is still very unclear. Scientists continue research on patient as to how and why this happens and what protein is made from the mutation. Solution There are many solutions to combat Huntington's disease. gene therapy is the method that I will be studying in this report. Gene therapy is a complex process which takes patience and resilience to complete.

    • Word count: 2665
  9. Marked by a teacher

    The problem of low genetic diversity in cheetahs and its effects on conservation.

    Domesticated species often have low levels of genetic diversity. This is caused by the artificial selection of crops and animals for the traits that humans want. While this can have positive short-term results such as a richer harvest or a prize winning breed low genetic diversity among domesticated species poses a risk because new virus or bacteria strand can invade a population of nearly identical organisms very rapidly killing them off but if there is a variation between them then there is a good chance Image1 Crufts winner best in show some of them will build up or have and immunity to it.

    • Word count: 2046
  10. Peer reviewed

    Problem - Maintaining the habitat of the capybara and breeding them for meat.

    4 star(s)

    Water is being abstracted for human usage increasing the threat to freshwater habitats. Efforts to protect wetlands have now produced several international agreements. Another habitat being destroyed is the grasslands, in the past grassland covered about two fifths of the earth's land surface 3.This grassland is being destroyed for agricultural use for growing crops or raising livestock. However, farming has created grassland; the hill pastures of Europe and New Zealand, for example, are a result of deforestation several centuries ago 3.This old pasture has a larger range of plants and vegetation, which nutritionally benefits the capybara and several other animals.

    • Word count: 2865
  11. Peer reviewed

    How Zoo's Avoid Inbreeding in a Limited Captive Population

    4 star(s)

    With more time, Inbreeding Depression can occur which is the decline of health and poor vigour of a population. Other factors can effect a population for example, Genetic pollution, uncontrolled hybridization, the bottleneck effect, small Gene pools. The term Line breeding is used by breeders of purebred livestock, where the animals are purposely inbred for planned characteristics and predictable offspring. Inbreeding depression is more likely to occur when populations of animals are breeding with relatives, this causes more homozygosity, with that in effect offspring inherit the recessive alleles of their parents, and Recessive alleles are mainly deleterious, thus giving the effect the name 'Inbreeding Depression'.

    • Word count: 2672
  12. Peer reviewed

    Is there a relationship between the girth of a tree trunk and the percentage cover of lichen?

    4 star(s)

    Only one species of tree shall be examined - sycamore trees. This eradicates any influence that could be made by varying amounts of lichen growing on different species of trees, narrowing down the variables to be controlled. Light intensity cannot be controlled, however it can and will be measured. Measuring light intensity could well indicate whether there is a photosynthesis component involved, which would add detail to the results and subsequent conclusions. It will be measured at each tree using a light meter. Light intensity will be measured at the one meter point on the north mark on all trees.

    • Word count: 2468
  13. Peer reviewed

    Issue report: 'Smart' Drugs

    3 star(s)

    However is this really the case? Economical Issues There are massive gains to be made from these types of drugs. Take for instance Modafinil it is a drug that reduces the amount of sleep you need over 4 days to 0 hours. Yes 0 hours. That sort of thing could mean that you could spend more time working and yet have more time doing things that you may want to do. The average business man spends 57 hours a week working, often meaning that he has little time to himself all week long.

    • Word count: 2177
  14. Free essay

    Cloning Reasearch Paper

    Human being has to face to new disease, which are incurable. Should we stay like this and no doing anything? Of course no! Our survival instinct tells us to act as scientist did before. We are able to create synthetic blood, to inject seven different gens in a cell in order to make this cell as a new one. We cannot say anymore that we are not playing god, we also modify genetically vegetable as corn. Is this more ethical than create a copy of an organ which already exist? Here we are going to see the historic of the cloning then why cloning might be a good thing and to finish we will see that clone an organ is defendable.

    • Word count: 2606
  15. Biology Reseach Project - Is Hormone Replacement Therapy safe?

    These studies range between different areas of medicine. In the 1990's a large study was done by the Women's Health Initiative that showed that HRT reduced the risk of osteoporosis and colon cancer but increased the risk of strokes, breast cancer, embolisms, and heart disease1. There was a further follow up study in 2002 by the same organisation in 2002 which concluded that there are more risks than benefits. However to date do doctors do have knowledge of these factors and fail to specify to patients? This is not the case; it is in the patient's best interests to make a uniform decision to whether their use of HRT will undermine their immune system.

    • Word count: 2584
  16. Photosynthesis. An experiment was carried out to determine how certain factors such as light intensity and availability of carbon dioxide, affected the rate of photosynthesis. The rate of photosynthesis was measure by the amount of oxygen produce (cm3/m

    This liming factor will control the maximum rate of the photosynthetic reaction. Photosynthesis takes place in two major parts: ATP and NADPH production (light reactions) and carbon fixation ("dark" reactions). - (Photosynthesis and the Environment , 1) Both processes are dependent upon each other - the relative concentrations of NADPH and ATP due to their consumption in the Calvin cycle influences photosystem mechanisms, and the amount of ATP and NADPH produced in the light reactions dictates how fast CO2 is fixed in the Calvin cycle. The Calvin cycle can be defined as a cyclical series of biochemical reactions that occur in the stroma of chloroplasts during photosynthesis.

    • Word count: 2595
  17. Phylogenetic tree - in 1866, Ernst Haeckel introduced the phylogenetic tree, or the tree of life. Until now, the theory about the existence of tree of life is still strong in most people thought. But in fact, is this the phylogenetic tree really exist? If

    If not, is Darwin wrong? The key point for the theory of the tree of life is homology. In 1848, Richard Owen introduce the term Homology to refer the structural similarities between two species that is not functionally necessary. According to Darwin, there are the structural similarities between species because they had all descended from their common ancestor. In the theory of evolution of Darwin, there are three conclusions: * Natural Selection ultimately produces evolution * The vast varieties of living creatures are a natural outgrowth of the vast ways to live within the environment, or niche that organisms can occupy.

    • Word count: 2171
  18. Biology Report - Effect of Environment on Phenotype

    This is the basis of my investigation. Although the plants are the same genotype and in the same condition, their root growth should differ because of the substance and its pH that is used to accommodate each plant. If the pH is higher than 7.4 then ions such as iron, Manganese, Copper, Boron and zinc become less available. When there is a deficiency then the plant's growth will slow down, resulting in no, or less root growth. It also affects the absorption of nutrients by the plants because when the pH is lower then 6, Phosphoric acid, calcium and magnesium become less soluble in water and it becomes difficult for the plant to absorb them, again inhibiting root growth.

    • Word count: 2202
  19. In this coursework I am going to investigate the different characteristics of cloning, how it came to be, the methodologies and how it works, and, in the process, determine its significance to humans.

    Humans have been using this vegetative technique in agriculture for thousands of years. The process has been helpful in environments where flowering and seedling establishment are infrequent. The table below shows the advantages and the disadvantage of plant cloning. Advantages of plant cloning Disadvantages of plant cloning A lot of new plants can be grown in a short time All plants have same genetic information so there is risk of diseases or pests Little space is needed No new characteristics All new plants inherit the same characteristics No variation Like plants capable of asexual reproduction, the eggs of some animals can grow into adults in a different environment besides the body of its parent.

    • Word count: 2096
  20. Biology Report. How Stem cell research can help enhance medical advancements

    This disease is caused by the insufficient formation and action of dopamine, which is produced in the dopaminergic neurons of the brain2. The source that provided me with this information was Wikipedia, although it is useful website to gain information from I do not believe it is reliable. The reasons for this is because it allows anybody who has access to the website to edit various articles, meaning that they could contain inaccurate or misguided information therefore it will not have the detailed knowledge sought for were it to be written by scientists.

    • Word count: 2045

    The pGLO plasmid contains the gene for GFP but also the gene for �-lactamase, which provides resistance to ampicillin. B-lactamase inactivates the ampicillin present on the nutrient agar, allowing bacterial growth. Only transformed bacteria will grow on plates that contain ampicillin. Only a very small percentage of cells take up the plasmid DNA and are transformed. Transformation solution - contains calcium chloride. The calcium cation neutralizes the repulsive negative charges of the phosphate backbone of the DNA and phospholipids of the cell membrane, allowing DNA to enter the cells. Heat shock - increases permeability of the cell membrane to DNA.

    • Word count: 2092
  22. List areas of science that have raised ethical or moral issues

    This was aroused during the creation of Dolly the sheep in 1997 which caused world interest and the scientific and ethical implications. The most known cloning technique is the reproductive cloning; however, there are three types of cloning techniques cloning technique. These tree types of cloning are DNA cloning, reproductive cloning and therapeutic cloning. DNA cloning Molecular cloning refers to the transfer of DNA fragment from one organism to a self- replication genetic element like a bacterial plasmid. Plasmids are self- replicating extra-chromosomal circular DNA molecules.

    • Word count: 2512
  23. Colour variation in Littorina littoralis on the upper, middle and lower zones of a rocky shore

    The upper zone of the rocky shore will be predominantly exposed to sunlight for most of the day. Although sea water does reach the upper zone, its coverage is very shallow, and would not completely block sunlight reaching the sea floor. Prolonged exposure to sunlight can cause Littorina littoralis to dry out and die, known as desiccation. However, a zone on the rocky shore which has no exposure at all to sunlight will be very unlikely to have any plants or seaweed there, as sunlight is needed for plants to photosynthesize. The seaweeds are the main source of food for periwinkles.

    • Word count: 2884

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