M6 C21 Manipulating genomes Flashcards
what is a genome?
minimum genetic material that contains 1 copy of all genes of an individual
what is gene technology?
the manipulation of an organisms dna to produce an organism or product
what are autosomes?
chromosomes that aren’t sex chromosomes
what is sanger sequencing?
stops dna synthesis due to modified nucleotides
what are non coding regions of DNA called?
introns
what are the 5 stops of producing a DNA profile?
extraction
digestion
seperation
hybridisation
development
what happens in extraction?
DNA is extracted in PCR
what does PCR stand for?
polymerase chain reaction
what happens in step 1 of PCR?
excess nucleotide bases are put into the tube woth the DNA that we want to copy and primers. this is then heated up to denature the hydrogen bonds between bases to seperate the DNA
What temperature is used in step 1 of PCR?
95 degrees
what happens in step 2 of PCR?
annealing of the primers are added to each separate strand, they signal where the DNA should start and end replicating.
what temperature is used in step 2 of PCR?
55-60 degrees
what happens in step 3 of PCR?
the extension of DNA as 2 taq polymerase molecules attach to the 2 primers on the 2 DNA strands. they move along the new strand as free nucleotides bind to the complementary bases.
what temperature is used in step 3 of PCR?
72-75 degrees as this is the optimum temperature of taq polymerase
what happens after the extraction of DNA?
digestion
what happens in digestion?
the strands of DNA are cut into small fragments by restriction enzymes at different points
what happens in seperation?
the fragments are then separated by gel electrophorisis
what happens in gel electrophoresis?
they seperate the fragments by legnth as the negative backbone is attracted to the positive elctrode at the end of the agar gel as an electric current is put through the gel
what size fragments move quicker in gel electrophoresis?
smaller fragments
what happens in hybridization?
radioactive or fluorescent DNA probes are added in excess to the fragments. they bind to the DNA strands separated in the gel and the excess is washed off
what happens after hybridization?
development of the evidence as the membrane with the dna evidence is put onto a x-ray film which reveals the dark bands where the dna is/ where probes have attached
what can DNA profiling be used for?
crime scene analysis
paternity tests
immigration relationships
see how at risk someone is for a particular disease
what is sanger sequencing?
radioactive labelling of bases
what is added in sanger sequencing?
DNA for sequencing is mixed with a primer, DNA polymerase, excess free nucleotides, terminator nucleotides
what happens in sanger sequencing?
heated at 96 degress to seperate the strands
cooled to 50 degrees to anneal the primers
heated agasin to 60 degrees so polymerase can create new strand by adding complementary bases
what happens when a terminator base is added instead of a ‘normal’ base?
the synthesis of dna is terminated as no more nucleotides can join
as there is a lower amnount of terminators compared to the nucleotides lots of different lenghts of fragments are produced.
what happens after many cycles of Sanger sequencing?
all the possible dna chains will have been produced. they are then seperated by length in capillary sequencing which works like gel lectrophoresis
what detects the final base on each fragment of DNA?
fluorescent markers on the terminator bases at the end of each sequence
how are the final bases recognized when sequencing DNA?
Lasers detect the different bases as they all have different fluorescent colors for each 4 bases this is then fed into a computer to sequence a genome
what can we use dna sequencing for?
bioinformatics- model biological systems, genes linked to certain diseases
sequencing the genome
identifying species
analyse pathogen genomes
look at eveloutionary relationships
what is synthetic biology?
genetic engineering
use biological systems in industrial context- drug production
synthesis of new genes to replace faulty
make a new organism
what are the principles of genetic engineering?
-genetically modifying dna from different organisms to produce recombinant dna
-genes are isolated from 1 organism and inserted into a other organism using a vector
what are the 1 way of isolating a gene in genetic engineering?
1- mrna extracted from cells to show what gene is being expressed. reverse transcriptase copies mrna back to cdna
how can a gene be isolated by restriction endonuclease in genetic engineering?
the restriction endonuclease cuts gene from the dna leaving sticky ends
what vectors are commonly used in genetic engineering?
bacterial plasmids
how is the gene inseretd into0 the plasmid/
restriction endonucleases cut open the plamsid leaving it with complementary sticky ends to the ends of the dna frament being inserted
what does dna ligase do?
forms phosphodiester bonds between the sugar and phosphate groups on 2 strands of dna joining them together
what does the plamsid do once inside a host cell?
combines with the host cells dna to form recombinant dna
how does the vector get into the host cell|?
place bacteria and plamsids in ca rich solution heated so bacterial mebrane is more permeable and plasmids can enter
how does electroporation get the vectors into the cell?
small electrial current is applied to bacteria makes membrane more permeable so plasmids can move in
what is electrofusion and how is it used?
tiny electric currents are applied to 2 different cells this then fuses the cell and nuclear membranes of the 2 cells so their dna becomes mixed
used in GM plants
what are reasons for genetically modified organisms?
increased growth
grows transplant tissue
resistance to pests
grwoth in harsh cinditions
better food security
medical benefits
what are some reasons against GMO’S?
losses for small farmers
playing god
exposure to allergens
health risks
resistant bacteria developing in humans
viability of offspring of GMO’s
toxic compounds in environment
tested on animals
