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AS and A Level: Genetics, Evolution & Biodiversity

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  1. Marked by a teacher

    The daphnia lab report

    3 star(s)

    Caffeine abuse causes palpitations, tremors, diarrhea, nausea, chest pains, sweating, vomiting and neurological symptoms. Addicts develop tolerance for caffeine and require a higher dosage every time to achieve the desired effects (Hasan 24). Early studies showed that high levels of Caffeine made the heart beat abnormally fast and constricted cerebral blood vessels in the human brain. Therefore, if a caffeine addict decided to stop drinking coffee for a day, their blood vessels would dilate resulting in a powerful headache. Other symptoms include fatigue and melancholy when withdrawing from caffeine (Caffeine). Caffeine's sensitivity varies from human to human but high levels of caffeine isn't good for the human body, as it is linked to restlessness, insomnia, anxiety, stress, heart irregularities and an increase in blood pressure.

    • Word count: 3009
  2. Marked by a teacher

    Thalassemia is a genetic (inherited) conditions affecting the blood. There are different types of thalassemia.

    3 star(s)

    Thus, the blood is in the 'surplus' mode, which can lead to symptoms and complications. (Nassar, Rechdan, 2006) Depending on the type of thalassemia, the number of abnormal hemoglobin is different. This can be a big part of the body of hemoglobin, and only a small percentage. This is basically what determines how serious to have thalassemia. There are also other individual factors. Thus, two people with the same type of thalassemia may have different severity of the disease from one state. (Nassar, Rechdan, 2006) Beta-thalassemia major Anyone with beta-thalassemia major, two genes of beta-thalassemia. Most of their hemoglobin is abnormal and does not work. This leads to severe anemia, beginning around age 4-6 months.

    • Word count: 1660
  3. 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
  4. Marked by a teacher

    Can The Use Of Stem Cells Be Justified?

    3 star(s)

    Labnotes - stem cells: potent research January 2003 This is a strong view taken by many religious people because of their belief that all life is sacred and life starts at the moment of fertilisation, so a fertilised cell should have the same status as a human being. Others argue that an early embryo is just a ball of cells, so it cannot have any rights. Edexcel 360 science 2006 Is it right to allow suffering to continue when it might be alleviated? At the end of 1998, two groups of scientists developed a technique for culturing embryonic stem cells.

    • Word count: 1053
  5. 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
  6. 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
  7. 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
  8. Marked by a teacher

    'Discuss the advantages and disadvantages of the use of gene technology.'

    With this information, parents have the choice of keeping the baby or not, to spare it from a seriously impaired or shortened life. An exciting and likely prospect in medicine is gene therapy, which is being tested currently. This would allow doctors to cure a disorder which was a result of a defective gene, and the first successful attempt was made where the gene encoding the enzyme adenosine deaminase was transferred into the bone marrow of two girls suffering from a rare blood disorder caused by the lack of this enzyme.

    • Word count: 1699
  9. Peer reviewed

    An Investigation into the effect of caffeine on reaction times

    5 star(s)

    Reduced adenosine activity also contributes to increased dopamine activity5, a neurotransmitter which is a precursor in the production of epinephrine6. Together, these effects increase the levels of epinephrine in the brain. ADHD (attention-deficit hyperactivity disorder) is caused by a deficiency in dopamine, and its treatments raise dopamine levels7. This suggests that dopamine also plays a part in attention and concentration. Synapse showing antagonistic action of caffeine on adenosine receptors - http://www.snabonline.com/pupil/mediabank.aspx -> Book artwork with no labels -> Figure 8.57 - 22/10/08 As well as blocking adenosine receptors, caffeine also blocks the removal of cAMP (cyclic adenosine monophospate) from cells.

    • Word count: 4449
  10. Peer reviewed

    Discuss the Impact of Genome Sequences on the Study of Development

    5 star(s)

    Despite it's hazy and undramatic origins the field aquired a recognisble unity by the 1930's. One proposed question was "how do the organisms' genes produce their effect in development?" This lead to the field of developmental genetics, using the genes of an organism to explain it's development. During that period Lillie (1927) Spemann (1938) and Just (1939) said there would be no genetic theory of development until: 1. Genetisists could explain how chromosomes produce different and changing types of cell cytoplasms. 2. Genetisists could explain how genes control the earley stages of development. 3. And explain how complex phenomena, such as the sex determination mechanisms occur.

    • Word count: 1908
  11. 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
  12. Peer reviewed

    Brewing. During beer production the sugar in the wort is fermented by the yeast into alcohol. For this purpose yeast fungi of the species Saccharomyces cerevisiae are used.

    4 star(s)

    Yeast is able to utilise these sugars both in the presence of oxygen and when oxygen is excluded. The aerobic breakdown, which produces more energy is called respiration and the anaerobic breakdown, which produces less energy is called fermentation. Of the carbohydrates only sugars are respired or fermented by yeast. An important parameter for distinguishing individual yeast species is their ability to respire or ferment various sugars. Whether a sugar is used aerobically or anaerobically depends principally on the oxygen availability. In the presence of oxygen, yeasts obtain their energy by respiration. When the oxygen is removed metabolism changes to fermentation.

    • Word count: 1451
  13. Peer reviewed

    For each of the animal groups you have chosen, describe the structures involved in the biological process you have named. In each case, describe how these structures function, and explain how they allow each group to survive in their habitat.

    4 star(s)

    This allows the insect to have a high metabolic rate - so they can fly. Insects can also open and close their spiracles which allow them to control water loss and allows insect to live in extremely arid conditions Fish: Fish live in an aquatic environment. As water contains less oxygen than air they have developed a very efficient gas exchange system. Gas exchange takes place at the gills which are specialised structures. They have several adaptations to increase the rate of gas exchange. Gills are thin and covered in lamellae this gives the gills a very large surface area.

    • Word count: 1456
  14. 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
  15. 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
  16. Peer reviewed

    The arguments for and against developing a “genetic fingerprint” profile for all members of society

    4 star(s)

    The enzyme makes two incisions, one through each of the sugar-phosphate backbones (i.e., each strand) of the double helix without damaging the nitrogenous bases (http://en.wikipedia.org/wiki/Restriction_endonuclease, 02/03/2008). Now the DNA sections can be separated by the process of electrophoresis, which is a technique, used in the laboratories that result in the separation of charged molecules (http://www.life.uiuc.edu/molbio/geldigest/electro.html, 02/03/2008). Because DNA is a negatively charged molecule, it is able to move through a matrix of agar when an electric current is passed through.

    • Word count: 1240
  17. 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
  18. Peer reviewed

    The cloning of Dolly.

    4 star(s)

    Cloned animals will be living in factories that would be able to produce a range of human drugs to helps us with various illnesses and maybe even diseases. The purpose of cloning Dolly was to see if the idea of a different way to producing animals, would actually work. Cloning mammals means that you can use larger animal types. Definition of terms What is cloning? Cloning is the production of genetically identical animals or humans using laboratory-grown cells. The term cloning (derived from the Greek word klon, meaning "twig")

    • Word count: 4230
  19. 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
  20. 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
  21. 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
  22. 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
  23. Mendels Inheritance Experiment. A class practical was carried out on purple fruit maize cobs and yellow fruit maze cobs where the individual kernels (fruits) were able to be identified

    The monohybrid cross is used to determine the F2 generation from a pair of homozygous grandparents (one grandparent dominant, the other recessive) which results in an F1 generation that are all heterozygous; crossing two heterozygous parents from the F1 generation results in an F2 generation that produces a 75% chance for the appearance of the dominant phenotype of which two thirds are heterozygous, and a 25% chance for the appearance of the recessive phenotype, this cross was originally used by the biologist Gregor Mendel who crossed two pea plants to obtain a hybrid variety which lead to discovering the possible changes in phenotypes of various alleles as previously mentioned.

    • Word count: 1765
  24. Chlamydia is the most commonly reported STD in the United States today.

    The only way to conceive such infection is through oral, vaginal, or anal sexual contact with an infected partner. Chlamydia bacteria can live in vaginal fluid and semen. The reason that there are so many cases left unreported is that about 70 percent of chlamydial infections have no symptoms what so ever, thereby naming it the "silent" disease. If you do happen to be infected, symptoms will usually appear in 1 to 3 weeks.

    • Word count: 603
  25. Cystic Fibrosis is one of the UK's most common inherited diseases and is life-threatening.

    This causes thick, sticky mucus and very salty sweat. However some research suggests that the CFTR protein also affects the body in other ways which supports the other symptoms and complications that cystic Fibrosis has. More than a thousand known defects can affect the CFTR gene and the type of mutation can affect the severity of the disease. Other genes also may play a role in how severe the disease is. (2) Figure 1 shows how CFTR genes are inherited.

    • Word count: 1022

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