5.16 describe the stages in the production of cloned mammals involving the introduction of a diploid nucleus from a mature cell into an enucleated egg cell, illustrated by Dolly the sheep

5.16 •cloning an adult mammal is done by transplanting a nucleus e.g Dolly the Sheep

                  •1. nucleus of sheep’s egg cell was removed, creating an enucleated cell 

                  •2. a diploid nucleus (full paired set of chromosomes) was inserted in it’s place, from a mature udder cell of a different sheep 

                  •3. the new cell was electrocuted so it started to divide by mitosis

                  •4. the dividing cell was implanted into the uterus of another sheep to develop until born  

                  •5. the result was Dolly, a clone of the sheep that the udder cell came from 

5.15 understand how micropropagation can be used to produce commercial quantities of identical plants (clones) with desirable characteristics

5.15 •(see above) In micropropagation, plant clippings are taken and put in a growth medium. They will develop into a new plant with the same DNA. 

        •this means they have the same characteristics. 

        •many clippings means many clones

5.14 describe the process of micropropagation (tissue culture) in which small pieces of plants (explants) are grown in vitro using nutrient media

5.14 •micropropagation is used to clone plants  

                  •a plant with desirable characteristics (e.g large fruit) is selected to be cloned 

                            •1. explants (small pieces) are taken from the tips 

                            •2. the explants are sterilised to kill any microorganisms 

                            •3. the explants are then grown in vitro (in a petri dish containing a nutrient medium) - the medium contains growth hormone  

                            •4. cells in the explants divide and grow into a small plant and further ones can be taken until enough small plants are produced 

                            •5. small plants are taken out and put in glasshouses, and are genetically identical 

5.13 evaluate the potential for using genetically modified plants to improve food production (illustrated by plants with improved resistance to pests)

5.13 •genetically modified plants can improve food production

                  •can be made resistant to inspections of plant killing chemicals

                  •making crops insect-resistant means farmers don’t have to spray as many pesticides, killing weeds without affecting the crop increasing yield  

                  •some have longer ripe fruits, contain more vitamins, produce human antibodies, tolerate drought and a variety of temperatures 

                  •concerns include transplanted genes getting out into the environment and creating a ‘superweed’ variety  

                  •could affect food chains and human health and other unforeseen problems, passed down onto future generations and are expensive for LEDCs 

5.12 understand that large amounts of human insulin can be manufactured from genetically modified bacteria that are grown in a fermenter

5.12 •as mentioned above, the bacteria containing the gene for human insulin can be grown in huge numbers in a fermenter, which has paddles to stir, provide it with nutrients, control

         pH, temperature and gases

5.11 describe how plasmids and viruses can act as vectors, which take up pieces of DNA, then insert this recombinant DNA into other cells

5.11 •vectors can be used to insert DNA into other organisms 

        •a vector is something that’s used to transfer DNA into a cell

        •there are two types - plasmids and viruses 

                  •plasmids are small and circular molecules of DNA that can be transferred between bacteria 

                  •viruses insert DNA into the organisms they infect

        •process of genetic engineering

                  •1. the DNA you want to insert e.g gene for human insulin) is cut out with a restriction enzyme and the vector of DNA is cut open as well 

                  •2. the ligase enzymes join is added and joins the gene and vector DNA, producing recombinant DNA  

                  •3. the recombinant DNA is inserted into other cells e.g bacteria  

                  •4. these cells now use the gene you inserted to make the protein you want

5.10 describe the use of restriction enzymes to cut DNA at specific sites and ligase enzymes to join pieces of DNA together

5.10 •enzymes can cut up DNA or join DNA together 

                  •restriction enzymes recognise specific sequences of DNA and cut the DNA at these points

                  •ligase enzymes are used to join the two pieces of DNA together 

                  •two different bits of DNA stuck together are know as recombinant DNA