biology-dna technology

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Bethany 123

Cards (23)

what are the grooves in DNA used for
-they are sections of the DNA that unwind so that replication and transcription can occur
-they also act as binding areas that allow for specific functions to be performed
what are the aims of genetic engineering
-to remove a desiered gene and transfer it into another organism
-this is done so certain proteins can be made within the new organism
what are some uses of genetic engineering
-the production of insulin in diabetes treatment
-used in the human growth hormone
-can be used as a factor viii to treat haemophillia
what is factor 8 and haemophillia
-factor 8 is known as a blood clotting agent
-those with haemophillia dont have this gene so the blood dosent clot.
how is DNA cloned
-isolate:fragment of DNA that contain the desired gene is isolated
-instert: it is then inserted into a vector
-transfer:the vector is transferred into the host cell
-identify: which cells have taken up the plasmid of DNA in the vector
-grow:the population of the new cells multiplies
how are the genes isolated
-the genes are transcribed into RNA which is extracted from cells in a lab
-an enzm known as reverse transcriptase takes RNA and makes DNA
-the DNA produced is now known as copy DNA/cDNA
why is RNA extracted not DNA
RNA is easier to obtain thatn DNA as there is more of it
what is cDNA amplification
where more cDNA ismade using the polymerase chain reaction
what are the stps to obtaining the gene of intrest
-cells containg RNA are grown in a lab
-then the RNA is extracted into a test tube
-where the reverse transcriptase is added and cDNA is made
-this is then amplified using PCR
-after this the ends of the cDNA are cut using a restriction enzyme
what is the role of restriction enzymes  
-to cut DNA
-sometimes the cut is made between the adjacent G and C leaving a blune end where there are no exposed bases
-other times the ends of the cut have a overhanging piece of DNA this is known as a sticky end
-these sticky ends can bind to their complimentary base pairs.
what si the role of DNA ligase
-the restriction enzyme cuts the DNA leaving sticky ends
-these pair up with their cmplimentary bases
-DNA ligase binds thes two pairs together
what are the steps to PCR
-first the sample is heated to 94 so that the double strands separate and the enzymes denature
-then it is cooled down to 55 where the primers anneal to the DNA
-at 72 the taq polymerase synthesises a new strand of DNA
what is a primer  
a specific short sequence of DNA that is complementary to the gene of intrest
what is taq polymerase
-DNA polymerase that is extracted from baceria as it wont denature during the first step of PCR
what are some examples of where DNA can be found
-blood
-hair
-semen
-saliva
what are VNTRs
-variable number tandem repeats
-non coding sections of DNA
what ia the process of gel electrophesis
-the DNA genome is cut into fragments by restriction enzymes
-they are then loaded into wells at the end of an agarose gel where an electric current is passed through the gel
-DNA has a negative charge so is attracted and will migrate towards the positive electrode
-resulting in the fragments being separated and being shown as bands of DNA down the gel like so:
what is the meaning of genotype and phenotype
-genotype is the gentic composition of an individual
-phenotype is how that gene is expressed this is influenced by the genotype and the environment
what is the meaning of heredity
the passing on of genes through reproduction
what is an autosome
a chromosome that doesnt determine the sex of an individual
how is cystic fibrosis passed on through reproduction
-recessive
-2 alleles are needed for the gene to be expressed
-if only one is inherited then that person is a carrier of cystic fibrosis
how is huntingtons disease passed on through reproduction
-dominant gene
-only need one allele for the gene to be expressed
-no carriers of this gene
how is haemophillia passed on through reproduction
-X-inked disease
-found on the X chromsome