B7- Miscellaneous

Frage	Antworten
Why is micro-organism farming useful?	They have relatively simple biochemistry biochemistry; they reproduce very rapidly; they can be farmed on a large scale to produce complex, useful molecules; they can be genetically engineered to produce further valuable chemicals; there are few ethical concerns about the way that a microorganism is treated.
How could microorganisms be used to make food?	Bacteria can produce bacteria very quickly but are difficult to harvest because they are very small. Yeast is easier to harvest but grow more slowly and produce lower-quality protein. The output of protein from microorganisms is much more efficient than that from animals.
What are fermenters?	Large steel vessels used by drug companies to make useful products such as penicillin which are produced by particular fungi. Temperature and pH are very carefully controlled so the maximum amount of product is produced as cheaply as possible.
What are selective herbicides?	Chemicals that kills certain plants but leaves others untouched
What happens over time with selective herbicides?	Weeds become resistant to them.
How are new selective herbicides produced?	A new herbicide is developed that kills both crops and weeds. Genetic engineers find genes that give plants resistance and add these to the crop plants. This gives a new, powerful and safe herbicide.
How has insulin been produced for people with diabetes over time?	It used to be extracted from the pancreases of pigs and cows but it was expensive, needed to be purified to avoid contaminants and there were religious and ethical implications. In 1982 a method was found for producing human insulin using bacteria. A method of genetic engineering was used to produce insulin by taking a human gene and inserting it into the bacterium E.coli.
What is recombinant DNA? How is it done using plasmids.	When DNA is combined from different sources. A vector, either a plasmid or virus is used to transfer a gene from one organism to another. First the gene is located an duct out of original chromosome, then enzymes are used to multiply it. Plasmids are circular DNA molecules found in some bacteria. The gene copies are mixed with plasmids, some of these plasmids open up and the gene is inserted into these plasmids. The plasmids then close up and can be multiplied by more enzymes. Plasmids are then inserted into bacterial or plant cells. The gene is then expressed when the modified cell develops.
How can be viruses used for recombinant DNA?	Viruses are microorganisms that are able to inject DNA directly into another cell. The cell then duplicates the DNA from the viruses as if it were part of its own genetic material. Inserting the required gene into the virus means this gene will be duplicated and become part of the organisms DNA.
How is recombinant DNA being used to try and cure cystic fibrosis?	A certain gene, that codes for the production of a protein that controls how fluid passes across a cell membrane. Because those with cystic fibrosis don't have this gene their lungs fill with fluid that interferes with their breathing. The virus-like particles are sprayed into their nose and pass down to the lungs. The gene is injected into cells and they are able to make the protein they need to stay healthy.
What is FISH testing and how does it work?	Fluorescence In Situ Hybridisation can be used to fin particular genes in a person's cells. First the researcher will prepare a length of DNA called a DNA probe, that can bind to a particular gene. The probe can do this because the two strands of the DNA molecule are mirror images of each other- if you have one then the matching opposite strand will be able to react with it. The probe is then labelled with a chemical that glows in ultraviolet light. The probe is mixed with a sample of DNA from the patient, usually from the white blood cells. If the probe finds the matching gene it binds to it and, when it is exposed to UV light glows. The glow tells the researcher that the gene is present. The FISH technique is useful for testing for the presence of genes we know make certain illnesses more likely. It is used particularly for testing before birth.
What are the ethical implications of predicting possible illnesses?	Should the fetus be aborted if they have an increased risk of getting a disease in later life? Could it go further, e.g. aborted because they have the wrong eye colour. Also once born could people struggle to get insurance or a job because they are likely to suffer from an illness. Could genes be brought and sold in the future through gene transfer techniques?
What is nanotechnology?	Technology which works at the scale of atoms and molecules. Usually between 0.1 and 100 nanometers (nm). One nanometer is one billionth of a metre.
How can nanotechnology be used in food packaging?	Food tends to go off because it reacts with oxygen in the air. Food packaging often lets oxygen seep through, but new packaging with nanotechnology makes this much more difficult. It also reduces the rate at which water can leave the food. This increases the shelf life. Some food packaging now includes nano-particles that change colour is packaging is damaged or the temperature rises above a certain level. Some nano-particles can even detect contaminants in the food.
How can nano-particles be used in medicine? (get 2)	Plasters which contain silver nanoparticles are now available, these have an antibacterial property which stops the wound going septic. Another use is gold-plated nanobullets used to destroy cancer cells. The scientists attach the particles to antibodies that only bind to cancer cells. When infrared light is passed into the body the gold particles heat up and kill the cells to which they are bound. Another company which use similar technology. It embeds, in a special coating, a compound that gives out electrons when exposed to X-rays. The coating allows the compound to enter tumour cells. A small dose of X-ray produces a large supply of electrons that kill the cancer cells.
How can medicine be used to help the heart?	Heart valves can now be replaced by artificial ones or ones from pigs which have been bred to reduce the problem of rejection. A pacemaker tells the heart when to beat. If the pacemaker does not detect a contraction within a certain time, it will give it a small shock to make it contract.
What are stem cells and what can they do?	Undifferentiated cells that can reproduce themselves to give identical undifferentiated cells or differentiate into any sort of cell they are required to. Stem cells injected into a damaged organ may be able to replace dead tissue by developing into the cells that make up those tissues. They could also replace nerve tissue, which could repair a broken spinal cord. They are also used to treat leukaemia by replacing faulty bone marrow cells so that enough red blood cells are produced (the bone marrow cells is killed using powerful drugs and radiation)
What are the sources of stem cells?	Cells from a very young embryo called embryonic stem cells. Fetal cells extracted from an aborted fetuses organs. Adult stem cell are stem cells in children and adults that are available from many different sites. Stem cells taken from amniotic fluid are called amniotic stem cells, and can be extracted without any harm coming to the fetus.
How is stem-cell research controlled?	Researchers must get permission to harvest these cells. Try to provide the greatest benefits for the largest possible number of people. Sometimes this is controversial. Some people believe that it is wrong to ever use cells from a human embryo, others believe the potential cures that may come from this research are more important than other arguments.

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