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AS and A Level: Genetics, Evolution & Biodiversity

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  1. Genetic Engineering - soon to become a mainstream part of our lives

    These substances are very important in some people's lives. Genetic Engineering can also allow for animals and plants to be 'tailor made' to show desirable characteristics. Genes could be manipulated in trees for example, to absorb more CO2 and reduce the threat of global warming. Genetic Engineering in plants could also help plants become resistant to disease or lack of water, helping them to live longer and increasing yield. Increasing yield would obviously be a tremendous help in poorer countries where people's lives depend on their yield.

    • Word count: 645
  2. Genetic Engineering; Magician or Monster.

    Disease could be prevented by detecting people, plants, or animals that are genetically prone to certain hereditary diseases, and preparing for the inevitable. Gene therapy can be used to fix defective genes or to replace missing genes. Many diseases are the result of just one gene malfunctioning; sickle cell anaemia, cystic fibrosis, are all caused by one defective gene. To correct the problem, gene therapy is used to deliver genes that function correctly. Genes could also be manipulated in trees for example, to absorb more CO2 and reduce the threat of global warming.

    • Word count: 632
  3. Genetic disorders that can be revealed by kariotype analysis.

    * Aneuploidy - condition in which in one pair of chromosomes there is one more (trisomy) or one fewer (monosomy) chromosome than there should be. It is the most common form of chromosomal aberrations (1/200 newborns) and some of them will be described here. The interesting fact is that it is estimated that chromosomal aberrations occur in some 7.5% of all zygotes. Most of them is lethal though, as e.g. 60% of miscarriages occurring spontaneously in first three months of pregnancy are caused by chromosomal aberrations. Only 0.5% of newborns show such genetic disorders. The most common general symptoms of aneuploidy are general development retardation, many developmental defects.

    • Word count: 787
  4. The use of recombinant technology can only benefit humans. Discuss.

    Indge, Rowland and Baker (2000) summarises some of the ways that recombinant technology has been beneficial to humans; > Genetically engineered micro organisms- large amounts of insulin and human growth hormone can be produced cheaply. > Genetically modified plants- Desirable plants can be transferred from an organism to a crop plant. > Genetically modified animals- human proteins such as haemoglobin and blood-clotting factors, are already produced in the milk of transgenic cows, goats and sheep. > Human gene therapy- gene therapy involves inserting a 'normal' gene into an organism's body to correct a genetic disorder.

    • Word count: 689
  5. DNA Fingerprinting.

    The rest consists of non-coding sequences of bases called introns, which occur between or within a gene. Introns can be between 60 and 100 000 bases long. A single gene can contain 50 introns between exons (coding parts of the DNA molecule). The function of introns is unknown. Within non coding regions between genes there are short sequences of bases called core sequences that repeat themselves over and over again, sometimes up to 100 times. These repeated regions of DNA are called mini-satellites or variable number tandem repeats. Different people have different numbers of repeated core sequences; therefore they have different sized mini-satellites.

    • Word count: 819
  6. What are Genetically Modified Foods?

    from one species and transferred it into another. This enables the transfer of a desired characteristic between unrelated species, or between plants and animals. For example, an 'antifreeze' gene which appears naturally in Arctic fish has been introduced into tomatoes and strawberries, thus making them freeze-resistant; and pigs have been genetically engineered with a human gene introduced to make them grow more effectively. The advocates of genetic engineering say it could be a solution to the world's most intractable food problems. Genetically modified foods will be beneficial to everyone,' says Jackie Dowthwaite, spokeswoman for the Food and Drink Federation (FDF), which represents the UK's food processing industry.

    • Word count: 675
  7. The use of genetic engineering can only benefit humans.

    We likely will learn many other possibilities as we learn more about DNA and how the cell functions. The set of techniques used to manipulate DNA is known as genetic engineering. (www.isbe.state.il.us/.../...Engineering.htm) Genetic engineering is a complex technique, which needs special enzymes called restriction endonucleases, which chops up DNA strands at individual specific locations (sites). (Heinemann Advanced Science by Ann Fullick) This new method of engineering is very beneficial to human beings because genetic engineering has, for example, made it possible to detect, and in some cases treat, diseases such as sickle-cell anaemia, diabetes and cystic fibrosis. Following initial concerns that genetic engineering could give rise to infectious organisms, the spread in which would be difficult to keep contained.

    • Word count: 958
  8. Critically discuss the view that eating disorders are caused by genetic and biological factors. With reference to the biological and genetic explanations whilst also trying to offer alternative explanations.

    - They have an intense fear of gaining weight, but are often obsessed with food - They have a disturbed body image- they usually continue to see themselves as overweight - It is usually accompanied with amenorrhoea - It is largely a problem with middle class and adolescent girls. - Two types of anorexia have been identified; the restricting type (constant fasting) and the binge eating type (those who periodically binge and then purge) Bulimia Nervosa is a more common problem than anorexia and probably more related to dieting.

    • Word count: 842
  9. The Human Genome Project.

    There are about 2.9 billion base pairs in the human genome wound into 24 distinct bundles, or chromosomes. Written in the DNA are 30,000-40,000 genes which human cells use as templates to make proteins; these sophisticated molecules build and maintain our bodies. Proteins are large, complex molecules made up of long chains of subunits called amino acids. Twenty different kinds of amino acids are usually found in proteins. Within the gene, each specific sequence of three DNA bases (codons) directs the cells' protein-synthesizing 'machinery' to add specific amino acids. The Human Genome Project was officially started in 1990 by the U.S.

    • Word count: 832
  10. The Advantages and Moral Dilemmas of Human Cloning.

    Cloning began by curiosity and built itself into a geneticist's way to replicate various genetic materials such as gene segments and cells. When it was discovered that the cells could be reproduced, it eventually led them to think that just maybe a whole organism could be cloned. They worked up to larger and larger organisms and finally Dolly arrived. She was made through a cloning process that generally takes a fair amount of time. It all starts when the scientists transfer the nuclei from the various types of sheep cells into unfertilised sheep eggs from which the natural nuclei had been removed by surgery.

    • Word count: 831
  11. Homeotic genes are defined as a gene, mutations in which result in the transformation of one body part into another.

    Lewis conducted work concerning Drosophila fly development, - How the genes causing them co-operate during body segmentation. His research on the genetic basis for so-called homeotic transformations during embryonic development was the now famous Drosophila-mutant with legs in the place of antennae. He found that homeotic genes control specialisation of the segments. In the mutant case, inactivity of the first gene in a complex of homeotic genes (antennapeadia gene) caused other homeotic genes to duplicate and therefore transform antennae structures (normally in the head)

    • Word count: 663
  12. A Method to Clone and identify the V. stable.

    The very first step in the cloning of the glucuronidase gene is to break up the DNA into manageable sized fragments using restriction enzymes. The site of cleavage is at the unique restriction site BAMH1. At the same time the vector is also prepared. The vector chosen for this experiment is pBR322 (see fig below) The reason for using this particular plasmid vector is that it has its own origin of replication, which ensures the multiplication of the vector, it has a copy number that is reasonably high which can be further increased, and two selectable markers, both of which can be involved in insertional inactivation upon fragment insertions.

    • Word count: 977
  13. In what sense does Dawkins think that our genes are selfish? Does his view make sense?

    This molecule had the remarkable ability to create copies of its own. And so it went. The replicator started making copies were not always the same, and as the copying procedure continued the errors were getting cumulative and serious. These errors were essential for the progressive evolution of life. So from these errors there were varieties of replicating molecules that have been more stable than others, and others with more longevity that tended to me more numerous. As a result a competition began between them because the building blocks were used up at a rate that they became precious.

    • Word count: 969
  14. Describe and evaluate theories and empirical studies in the Biological Perspective.

    Such a study that has taken place can be Gottesman's (1991), who compared the Concordance (refers to the probability of both twins sharing a characteristic like schizophrenia) rates of MZs and DZs for schizophrenia, which is a serious mental disorder characterised by hallucinations, delusions and difficulty in thinking logically or rationally. The results from this test came out to be that MZs have a 48 % concordance for schizophrenia and DZs have a 17 % concordance for schizophrenia, showing that MZs have a much higher probability of sharing schizophrenia then DZs.

    • Word count: 828
  15. What is the biological role of sex?

    If organisms did not produce offspring, their species would become extinct. A zygote is formed when the sperm cell from a human male and the ovum from a human female meet in the fallopian tubes inside the female body. The sperm cells and ova are different to all the other cells in the human body; they contain only 23 chromosomes (half the number of the full complement of chromosomes). Why is it that the sex cells only contain 23 chromosomes? This is because a normal cell contains 46 chromosomes. If the sex cells sheltered this many chromosomes, when they came to fuse in the fallopian tubes, the resulting zygote would contain 92 chromosomes!

    • Word count: 842
  16. The human genome project.

    This 'provides a mechanism for maintaining and passing on the genetic information from one generation to another' 3 DNA is formed when these monomer nucleotides join together to from a polymer. DNA consists of a double strand, which twists, resembling a twisted ladder where the base pairs form the rungs. This DNA sequence is very important as it specifies the traits of a particular human beings. DNA carries the genetic information that codes for amino acids thus coding for proteins which have vital roles in the human body for example they make antibodies, enzymes and are blood carrier molecules.

    • Word count: 661
  17. The moral and ethical issues associated with recombinant DNA technology.

    These grew in a colony then they were put in to the patient like an ordinary blood transfusion"(4) and the girl lived, as this was a successful cure. Not many people will argue to curing genetically prone people, but it could get out of hand "in theory any desired gene could be instead into an human egg"(1) so how far do we go is the question, can we choose what are babes should look like?

    • Word count: 566
  18. Genetic Engineering.

    However it also provides medical benefits. The achievement of genetic operation will result in a better quality of life for people. Nearly all diseases can possibly be cured. As a result of genetic testing, the prevention of risks is also a benefit. For instance, if I find that I am genetically liable to have a heart attack, I can reform my habits around my genetic characters. Also if it is the result that genes open the power of the mind, then who is to say that someday people won't be able to hand pick their child and their qualities.

    • Word count: 578
  19. Argument on Genetic Engineering.

    The achievement of genetic operation will result in a better quality of life for people. Nearly all diseases can possibly be cured. Cancer will be treated as cancer causing genetic defects will no longer be a problem. As a result of genetic testing, the prevention of risks is also a benefit. For instance, if I find that I am genetically liable to have a heart attack, I can reform my habits around my genetic characters. Or, if I know that I have a recessive gene for a disease, I will know not to have a child by another person with that gene.

    • Word count: 628
  20. The dangers and concerns of gene therapy.

    Inside the lungs the liposomes fuse with the cell membrane 4) The DNA is can then be carried into the cell 5) The normal allele is transferred to the nucleus where it is transcribed Functional cystic fibrosis transmembrane regulatory channel proteins are produced and incorporated into the cell membranes,alowing chloride ions to leave the cell thus preventing the thick sticky mucus asociated with the symptoms of cystic fibrosis. The treatment is only temporary because the epithelial cells in the airways die and the new cells in their place do not contain the normal allele.

    • Word count: 977
  21. Human genome project.

    Gene therapy has also been revolutionised hopefully defective or missing genes can be replaced or added to cure genetic diseases. Understanding the human genome will help assess risks posed by exposure to toxic chemicals. Some people are less susceptible to these chemicals research into this will help scientists understand why this is the case. This can be vital to understand effects of exposure to radiation. Genome research will also help us to understand human evolution and the things we have in common with all life. By comparing human and animal genomes we can find out the functions of some genes.

    • Word count: 749
  22. Human Genome Project.

    The Human Genome Project has a lot of goals. Firstly its main goal is to identify all the 100,000 genes in human DNA. Secondly to determine the sequence of three billion chemical base pairs that make up the human genome, all this information has to be stored in a database. Tools for data analysis have to be developed. Related technologies have to be transferred to the private sector. Due to the ethical, legal, and social issues, which may arise from the project, it has to be addressed.

    • Word count: 617
  23. It is unlikely for us to worry about genetic enhancement is inevitable because there is skepticism arises from three sources: futurology and its limits, the science of behavioral genetics, and human nature itself.

    From these invisible predictions, we could hardly believe if the prediction about the "designers babies" is going to happen. The reason why technological predictions are usually wrong is because futurologists make prediction as current progress can be extrapolated indefinitely. They underestimate how much has to go right for a development to change of life, as it takes a large amount of discoveries, with the psychological and sociological imponderables that make people adopt some invention. This is about the same situation of the genetic enhancement from the fact that the development is just in initial period, but it is expected to become truth if research proceeds on its current course.

    • Word count: 788
  24. Arguments supporting and opposing the research carried out in the Human Genome Project.

    Successfully accomplishing these goals will demand the development of a variety of new technologies. It will also necessitate advanced means of making the information widely available to scientists, physicians and others in order that the results may rapidly be used for public good. Public are afraid that the total completion of the human genome project will give scientists the opportunity to manipulate the human make-up. The whole issue of genetics frightens people because they feel it is the fact that scientists intend to play "God".

    • Word count: 933
  25. Inherited sources of genetic variation.

    To increase genetic variation other larger and more complex organisms such as plants and animals reproduce sexually by Meiosis. Meiosis causes the formation of four daughter cells, however in female ova only one of these is usually functional, and the number of chromosomes in these daughter cells is haploid or halved, due to the cell dividing twice. The reason for the genetic information being halved is so that the zygote can contain half the information from each gamete or parent with out the number of chromosomes doubling with every generation. It is through this division that genetic variation can take place.

    • Word count: 765

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