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• light microscope pag description

  1. thin slice of specimen
  2. take a clean slide and use a pipette to put one drop of water in the middle - this secures the specimen in place
  3. use tweezers to place specimen on the slide
  4. drop of stain if your specimen is transparent/colourless
  5. cover slip at one end holding it an angle
  6. lower it and press gently with the needle so that no air bubbles are trapped under it
  7. clip slide onto the stage of the microscope
  8. select lowest power objective lens / coarse adjustment knob to move stage up so that the slide is just underneath / adjust focus with fine adjustment knob
• genome

  entire genetic material of an organism
• DNA

  DNA is a polymer made up monomers. Each monomer is made up of nucleotides. Each DNA molecule contains two strands of nucleotides which coil together to form a double helix.
• Phenotype

  Characteristic the organism displays
• Genotype

  Combination of alleles an organism has for each gene
• Chromosome

  One very long molecule of DNA that's coiled up
• Gene

  Short length of DNA on a chromosome
• Genetic variant

  Different versions of a gene
• Allele

  Different versions of the same gene
• importance of amino acids

  Each gene codes for a particular sequence of amino acids, which are put together to make a specific protein. This process of making a big molecule (eg protein) from lots of smaller molecule (eg amino acids) is called polymerisation.
• gamete

  reproductive cells
• homozygous

  two alleles that are the same for that particular gene eg. CC or cc.
• heterozygous

  two different alleles for that particular gene eg Cc
• dominant allelle

  version of the characteristics that appears
• recessive

  characteristic that does not appear unless both allelles are recessive
• what does the 23rd pair of chromosomes do

  determine gender

  XY == Male

  XX == female
• Y chromosome

  Carries a gene which makes an embryo develop into a male as it grows, by stimulating the growth of testes. Females who dont have Y chromosome dont have this gene so they develop in a different way
• potential importance for medicine of our increasing understanding of the human genome

  Scientists have identified all of the genes found in the human genome. This has lots of potential uses in medicine by comparing the genomes of people with and without a certain disease, scientists can try to identify the genetic variants that are involved in the disease. People can then be tested for genetic variants that are linked to particular disease.
• What is genetic engineering?

  Process which involves modifying the genome of an organism to introduce desirable characteristics
• main steps in the process of genetic engineering

  1. isolating and replicating the required gene
  2. putting gene into a vector (plasmid)
  3. using vector to insert the gene into cells
  4. selecting modified cells
• benefits of gene technology

  For example in agriculture, crops can be genetically modified to be resistant to herbicides. This means farmers can spray their crops to kill weeds without affecting crops. This increases crop yield.

  In medicine, genetically engineering bacteria to produce human insulin has helped to improve healthcare. Researchers have also managed to transfer human genes that produce useful proteins into sheep and cows. These proteins can then be extracted from the animal eg their milk.
• risks of gene technology

  It's hard to predict what effect modifying its genome will have on the organism - many genetically modified embryos don't survive and some genetically modified animals suffer from and some genetically modified animals suffer from health problems later in life. There's also moral concerns about the use of technology to modify human genes. It could lead to the creation of "designer babies" and parents choosing their child characteristics.

  2) Transplanted genes may get out in the environment. It could affect the food chains or even human health.
• How can genetic testing help to improve health care?

  1)Some genetic variants put you at higher risk of developing a certain disease. If people knew they had it, they could make lifestyle changes to reduce this risk.

  2)In the UK new-born babies are routinely tested for certain genetic variants so doctors can tell whether or not they've inherited a particular genetic disorder. If they have, treatment can begin early.

  3)Could also help create personalised medicine, doctors prescribe ones that are most effective for the patient.
• Drawbacks of genetic testing

  1. Increased stress - if people knew they were going to get a disease, they could panic.
  2. Discrimination - Employers may discriminate against people who are genetically likely to get a disease.
• Genetic testing (family planning)

  1. Parent

  2. Embryo

  3. Fetus
• Parent(Genetic testing)

  One of the parents may know there is a genetic disorder within the family. Genetic testing could reveal whether they are a carrier for the conditions.
• Embryo(Genetic testing)

  A couple who know they are at risk for passing on the genetic disorder may choose to have their eggs fertilised in a lab. A cell can be taken from each resulting embryo and its DNA analysed. An embryo without genetic variants linked to the disorder can be implanted into the womb to develop into a baby.
• Fetus(Genetic testing)

  Once a woman is pregnant, it's possible to get some of the fetal DNA by taking a sample of the amniotic fluid. This procedure carries small risk of miscarriage. The fetal DNA can then be tested for the genetic variants linked to the disorder.