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Paper 2 Biological diversity > Manipulating genomes > Flashcards

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All the genetic material contained by an organism


DNA profiling

1. Extract the DNA from tissue sample produced by PCR
2. Digesting the sample using restriction endonuclease
3. Separating the DNA by electrophoresis
4. Hybridisation (radioactive or fluorescent probes added to excess DNA in order to label the fragments)
5. Development (membrane with radioactively labelled fragments is placed onto X-ray film) - this reveals dark bands where the radioactive fluorescent DNA probes are attached.



1. Strands are separated at 90-95 degrees for 30 seconds, which denatures the DNA by breaking the H bonds.
2. Annealing the strands by adding primers to the ends of the DNA strands at 55 degrees. Needed for replication of DNA to occur.
3. Synthesis of DNA as temp is increased to 72-75 degrees for 1 min, so DNA polymerase can work best and add bases to the strands. Two new DNA fragments are produced.


Uses of DNA profiling

- criminal investigations
- forensic science
- proof of paternity
- checking if individuals are prone to certain diseases


Sanger sequencing/DNA sequencing

1. DNA is placed into 4 tubes and primers, DNA polymerase, and activated free nucleotides are added.
2. In each tube, chain-terminating nucleotides for one specific base are added.
3. Tubes are placed in a THERMOCYCLER and PCR begins.
4. PCR occurs until the DNA polymerase reached the CTN, where PCR stops.
5. The terminator base attaches at different lengths down the sequence, therefore, DNA strands with different lengths are produced.
6. Capillary sequencing (like gel electrophoresis) is used to separate them according to their length.
7. The end of each DNA strand can be identified by the fluorescent markers.
8. Order of bases in the capillary tube determines the sequence of the new DNA strand



Development of the software and computing tools needed to organise and analyse raw biological data.


Computational biology

Uses the data provided by bioinformatics to build theoretical models of biological systems, used to make predictions in certain circumstances.



- mRNA includes exons and introns, and introns have to be removed.
- exons to be translated are joint together by spliceosomes