8.1 RECOMBINANT DNA

what is biotechnology

technology that uses cellular processes to make products that are of use to humans.

what is artificial selection/selective breeding

A process where humans deliberately choose which organisms to reproduce to enhance or reduce specific traits in off spring. This involves selecting individuals with desired characteristics and mating them to produce new generations with those traits more pronounced. 

why do we use alternative processes

because artificial selection is a slow and inefficient process. Genes are passed on by chance and it is necessary to wait for the next generation to mature before knowing the outcome.

what is genetic engineering/recombinant DNA technology

it involves the artificial modification of DNA, where DNA is either added or removed from a cell.

the dna produced is called the?

recombinant DNA

and the organism is the?

genetically modified organism (GMO)

what are the possible uses of recombinant DNA technology

• introducing desired traits into organisms

• using harmless bacteria to produce proteins

• replacing faulty genes

• introducing DNA from a species into another species

what is the organism produced from introducing DNA from a species into another species?

transgenic organism

what is the aim of transgenic organisms

• to introduce a trait that is not normally present.

• All transgenic organism are GMO’s but not all GMOs are transgenic.

• One example is golden rice, developed to address vitamin A deficiency

who and how did a person invent the recombinant DNA technique

• Stanley Norman Cohen and Herbert Boyer invented the technique in 1973.

• technique was to isolate and amplify genes or DNA segment and insert them into a bacterial cell

• the introduced genes became part of the transgenic organisms DNA and could be passed on from one generation to the next.

what must be done for a genetic engineering to be possible

the gene for the desired trait must be identified then isolated

next the DNA gene must be “opened'“ and the gene is then added to the recipient and joins it’s DNA

what is a recognition site/recognition sequence

• certain enzymes in bacteria are able to resist the duplication of bacteriophages by cutting up the viral DNA.

• these enzymes always cut the DNA at a point where there is a certain sequence of bases.

what is a restriction enzyme

the enzyme that cuts the DNA, restricting the duplication of bacteriophages

what is a restriction enzyme an example of

endonucleases, enzymes that cut within a DNA molecule by separating two nucleotides.

some restriction enzymes produce different types of cuts, what are these?

• straight cut

• blunt end

• staggered cut

• sticky end

straight cut

• when the restriction enzyme makes a clean break across the two strands of DNA to produce a blunt end.

• a blunt end is when both strands terminate in a base pair

staggered cut

• results in fragments with sticky ends

• a sticky end is a stretch of unpaired nucleotides in the DNA molecule that overhang at the break in the strands

recognition sites are -

• four to eight base pairs long and are palindromic

• which means that they have the same sequence when read both forwards and backwards.

• this means that the same sequence occurs on both strands within the recognition site, therefore both strands will be cut, forming two segments.

what factors contribute to the type of cut a restriction enzyme will do

• the recognition of a certain base sequence

• the cut at a certain point