Flashcards
Gene Technology
Cards in this deck (26)
- 1Explain how DNA finger printing is done.1. Collection of the DNA sample. This can be collected from the hair, semen, blood, etc.
2. Extraction, we now need to extract the VNTRs - Variable Number Tandem Repeats. Those are repeats of DNA base sequences that are non coding / do not code for a protein.
3. Digestion - We need to use the enzyme restriction endonuclease to cut this DNA at specific sites called the recognition sites, into smaller pieces - this enzyme will cut close to the VNTRs but not within them so that they remain unique to every individual.
4. Seperation 1 - you now need to place this DNA fragment into gel electrophoresis. This will separate the DNA fragments according to their size, the smallest will travel the furthest and the largest will travel the shortest.
5. Seperation 2- you now need to transfer this DNA from the gel and into a nylon membrane.
6. Hybridisation - label the DNA, using a DNA probe, those probes are radioactive and they will bind to the VNTRS at the complementary DNA base sequence.
7. Development- an x-ray film is then placed over the nylon membrane, visible bands appear. - 2Describe how gel electrophoresis is done.1. A gel with wells along one edge is placed in a tank full of buffer, where each of the wells has the DNA fragment of the desired gene. Those DNA fragments have been cut using a restriction endonuclease and they have been marked radioactively or using a fluorescent protein.
2. The buffer is used to dissolve the DNA fragments.
3. the edge that has the wells full of the DNA will be connected to the negative terminal, so the other end is connected to the positive terminal. This is because DNA has a negative charge due to the phosphate group.
4. switch on the circuit
5. The DNA fragments will then move towards the positive terminal because they will be repelled by the negative terminal.
6. The shorter DNA strands will move further than the larger DNA strands.
7. shine UV light over the sample to see where the DNA fragments are if fluorescent gene was used
8. You can then transfer this DNA Into a nylon membrane where it can be dried and stored this is southern transfer. - 3what are DNA probes used for?DNA probes are used to identify which gene has the specific DNA base sequence that is desired by the scientists.
- 4What is used in genetic screening?DNA probes.
- 5Describe how DNA probes can be used in genetic screening.1. Gel electrophoresis takes place
2. Heat the DNA to 95C to denature the DNA, and breaking the hydrogen bonds between the complementary strands and obtain 2 separate DNA strands. Other techniques can be used such as placing the DNA into an alkaline solution or using DNA helicase.
3. Add DNA probes that have a marker gene attached to them such as a fluorescent gene or a radioactive gene.
4. Wash to get rid of any unbound DNA probes.
5. The DNA probe will bind to the complementary DNA base sequence, then you can put the DNA Unser UV light and the DNA with the complementary DNA base seuqnec to the DNA probe will fluoresce because the DNA probe has attached to it,
6. Thus proving that the person has the mutation and hence the person has the disease. - 6What happens in DNA microarray?1. Involves the use of a glass slide with many different DNA probes/ those DNA probes will have different DNA base sequences.
2. DNA sample will then be added to the slide, this DNA that is added will be single stranded, the double strand has broken by heating to 95C or using DNA helicase.
3. Then the DNA probe with the complemeneyaru DNA base sequence to any of the genes in the DNA strand will bind.
4. This DNA FRAGMENT is labelled with a maker gene.
5. The glass slide is then washed to remove any unbound DNA fragments
6. Then again put UV light on top of the glass or and if the DNA fragment did bind to any of the DNA probes it means that the DNA probe will fluoresce. - 7what is genetic counselling?This is when advice and information is given to people regarding their genotype/ their risk of genetic diseases and the outcomes.
The genetic councillor will speak to the people to see what the best form of treatment will be and if their child has a high risk of developing a certain disease, the genetic councillor will be able to inform the parents of this and discuss other plans such as IVF / and coucncellorwill inform patients of the psycholgical, economical and physiological issues associated with raising the child with a certain disease. - 8What are the 2 things that transcription factors can be?1. Activators - so they will increase the rate of transcription.
2. Repressors - so they will decrease the rate of transcription. - 9how can transcription factors act like activators?Transcription factors will allow the RNA polymerase to bind to the promoter region.
- 10how can transcription factors act like repressors?Transcription factors can bind to the promoter region and prevent the RNA polymerase from binding.
- 11Explain how oestrogen works.1. The ovaries will release oestrogen, in males the enzyme aromatase will convert the testosterone into oestrogen.
2. This oestrogen will then be carried in the blood plasma by a protein carrier because it is a steroid hormone, and is therefore lipid soluble and not water soluble.
3. The oestrogen will then bind to the complementary protein receptor on the CSM of the target cell and will enter the cell by simple diffusion via the phospholipid bilayer.
4. The oestrogen will then bind to a transcription factor, causing it to change shape.
5. The transcription factor's DNA binding site will change shape and the inhibitor is no longer complementary to the binding site and it released.
6. The transcription factor will then enter the nucleus via the nuclear pore and will bind to the complementary promoter region of the target gene.
7. This will then result In the binding of RNA polymerase to the promoter region as well.
8. Transcription will start, making the mRNA strand.
9. The mRNA strand can later on be translated into the protein that is coded for by that specific gene. - 12what is the role of the transcription factor?The transcription factor is there to stimulate the transcription of the gene by binding to the complementary promoter region of the target gene.
- 13what is a transcription factor?Those are proteins found in the cytoplasm of the cell, which enter the nucleus via the nuclear pore and bind to a specific promoter region and then start the transcription of the gene.
- 14what is epigenetic?This is the study of how environmental factors affect our DNA without affecting the DNA base sequence, resulting in heritable changes.
- 15what is the epigenome?Those are chemical tags that surround the DNA-Histone complex (chromatin).
- 16How do environmental factors affect our epigenome?1. Environmental factors will stimulate proteins to carry its genetic message inside the cell.
2. The message will pass to a specific protein which can be attached to a specific sequence of bases on the DNA
3. Once attached the protein has 2 possible effects. - 17what are the 2 possible effects once the protein stimulated by the environment has attached to the specific DNA base sequence?1. Methylation of DNA - involves a methyl group.
2. Acetylation of histones - involves an acetyl group. - 18What happens if we condense the chromatin? (DNA-Histone Complex)1. The DNA will be more tightly wound up or coiled
2. The transcription factor will not be able to bind to the promoter region because it is unaccessbile.
3. The gene cannot be transcribed and cannot be translated
4. Gene is not expressed and it is said to be silenced / switched off. - 19what happens in the decrease acetylation of histones?1. This means an acetyl group is being removed from the histone.
2. This wil result in a more positive charge in the histone.
3. The phosphate group in the DNA will have a negative charge.
4. there will be stronger forces of attraction between the histone and the DNA.
5. This will make the gene more tightly coiled/wound up, and so the promoter region of the gene cannot be reached by a transcription factor.
6. The transcription factor will not bind to the promoter region and the gene will not be transcribed or translated.
7. The gene is said to be silenced / switched off. - 20what happens when we increase the methylation of DNA?1. We are adding a methyl group, CH3, to the DNA, specifically to the cytosine.
- 21How does the methylation of DNA inhibit the transcription of DNA?1. Methylation will prevent the binding of the transcription factor to the promoter region because it will make the DNA more rightly wound up.
2. Will attract proteins that will induce deacetylation / condense the DNA making it less accessible by transcription factors. - 22Can the epigenome be inherited? How?Yes the epigenome can be inherited despite mechanisms in the egg and sperm cells that will remove all of the epigenome, some will still be left behind causing the offspring to inherit it.
- 23Do epigenetic changes affect our DNA base sequence?No,
but they will increase the frequency of mutations. - 24Explain how epigenetic therapy is done.1. Many diseases such as cancer are caused by epigenetic changes.
2. Drugs that affect the methylation of DNA or the acetylation of histones can be given to the person to reverse the effect.
3. Those drugs must be made specific/target specific cells to prevent the healthy cells from being affected.
4. Giving the drug to the person will result in the gene being either switched on or switched off. - 25Give 2 uses of epigenetic.1. We can use epigenentics in oder to determine what stage of a disease the person is in / diagnose the person - because the level of acetylation or methylation.
2. Treatment of diseases - 26Explain how RNA interference siRNA = small interfering RNA works.1. An enzyme will cut the double stranded RNA into smaller double stranded RNA molecules called small interfering RNA.
2. Those siRNA will then speerate, the hydrogen bonds between them will break.
3. One strand will then combine with a specific enzyme.
4. This strand will then carry the enzyme to the specific mRNA base sequence, and will bind to this complementary mRNA base sequence.
5. An enzyme will then be activated to cut the mRNA into smaller pieces.
6. This mRNA can no longer be transcribed or translated.
7. The gene will no longer be expressed.
Information
- Description
- Flashcards on Gene Technology , created by ray :) on 21/05/2018.
- Created by
- ray :)
- Views
- 0
- Rating