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21 Cards in this Set
- Front
- Back
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What is the Genome?
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The genome is the total of all the genetic material in an organism.
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What is the human genome project? |
1988-2003 started- international project- aim to discover sequence of all 23 chromosomes |
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How was the genome project done? |
- genome broken up, sequenced in sections - overlapping sections sequenced - analysed+put together |
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Why is it important to know the human genome |
- genetic diseases - DNA profiling |
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What were the aims of the genome project |
- identify all 20,000-25,000 genes in human DNA - find out where each gene is located - determine the sequences of the 3 billion base pairs - store in database- everyone has access too - find function of genes |
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What are the ethical issues of the genome project |
- may highlight genetic illness - influence abortions - increases pressure for gene therapy- prevent children inheriting genetic disease - embryo cannot consent - discrimination (jobs) - issues with insurance - lead to 'designer babies' - knowing risk of disease- cause stress - human rights invasion- genetic tests - data protection- access to genetic information |
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What percentage of dna is identical in all humans? |
0.1%- causes variation - used for DNA profiling the rest of genome 99.9% - involved in gene expression |
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Where is DNA found in prokaryotes and eukaryotes?
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Prokaryotes: DNA is found in the cytoplasm, in the main chromosomes and plasmids.
Eukaryotes: DNA is in the nucleus and in the mitochondria (plants: chloroplasts) |
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What determines the protein structure?
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The genes themselves
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What percentage of DNA codes for proteins (exons)? |
2% |
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What is gene/dna sequencing? |
Analysing individual stands of DNA/genes to find out the sequence of bases which make up that gene - it can be used to identify individuals (paternity/ court) |
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What does PCR stand for? |
Polymerase chain reaction |
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Why is PCR needed? |
DNA profiling needs 10,000 human cells - PCR use to amplify DNA so large enough sample can be used |
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What were the difficulties of first developing PCR? |
DNA heated to 90/5C to separate stands- destroys DNA polymerase - enzyme from bacterium used instead (evolve to survive heat) |
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Describe the process of PCR |
1. reactants mixed and added - Taq, DNA polymerase, primers, bases, buffer 2. heated to 90/5'C for 30 secs - dna separates 3. primers bind to DNA, 50/5'C for 20 secs 4. 72'C for 1 min+ DNA polymerase builds up DNA strand. |
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How many times is PCR repeated? Amount of DNA? Time? |
30 times, 1 billion copies of the original DNA, 3 Hours |
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What is the human genome project |
- project to find all the sequences of bases in each 23 chromosomes - identify all 20000- 25000 - stored in database - where genes are located |
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Explain the process of sanger sequencing |
- DNA strands chopped into smaller pieces - double strands separated - PCR - labelled terminator bases (labelled with flurescent/radioactive isotope) added to single strands of DNA - terminator bases incorporated into dna, strand halted - repeated 4 times for each terminator base |
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In sanger sequencing, what is added as reactants |
- DNA to be sequenced - normal nucleotides - 1 type of terminator nucleotide - primer - dna polymerase |
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How is DNA separated |
- gel electrophoresis - phosphate backbone negativity charged - dna placed in wells in agar - smaller fragments move further - photographic paper used to |
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