module 2 – biotechnology & gene technologies genetic engineering module 2 – biotechnology & gene technologies

learning objectives Understand why scientist genetically engineer organisms. Understand how recombinant plasmids are made. Understand how transgenic bacteria can be made. Understand how bacteria copy and transfer plasmids between each other.

success criteria State reasons why scientists genetically engineer organisms. Describe the steps involved in genetically engineering bacteria. Explain why conjugation in bacteria can lead to concerns in the healthcare sector.

starter Come up with reasons why we would want to genetically engineer organisms. Think, pair, share.

Why genetically engineer? The animals that farmers keep today, have been selectively bred over thousands of years. Cows used today for milk and meat production, do not look anything like the wild animals they are descended from. Humans have unwittingly, manipulated the genetics of various animals and plants over the last few millennia. Humans have only very recently, realised the great power of DNA technology. It is possible to manipulate genes in many ways, inserting them back into a genome, and then seeing new phenotypes emerge. What used to take many generations to occur, can now happen in a few weeks

wild cow jersey cow domestication & selective breeding

Individuals of the same species Individuals of different species Genetic Modification Every species has a genome, and every individual has its genotype. It is possible to alter the genotype of an organism by transferring genes between: There are many advantages to humans by doing either. Individuals of the same species Individuals of different species

Benefits to Humans Increasing the yield and nutritional value of animals/plants Production of the active ingredients of vaccines Developing crops that are resistant to extreme weather, such as drought and flooding. Developing pest and disease resistant crops Cultivating microorganisms for the production of medicines Developing crops that are resistant to herbicides

bacteria and plasmids

Inserting genes into Plasmids The real-life application of what we have just learnt, occurs when geneticists insert an animal or plant gene into plasmids. Plasmids are small loops of DNA which are found in addition to the large circular chromosome that bacterial cells possess. By inserting our chosen gene into a plasmid, the plasmid acts as a ‘carrier’, or vector, which we can then introduce back into a bacterial cell. Restriction Endonuclease Restriction Endonuclease A plasmid DNA coding for a desired protein As the DNA fragment was cut out using the same restriction endonuclease as used to cut the plasmid open, they have complimentary sticky ends. Remember, that DNA Ligase would once again be used to bond the sugar-phosphate backbones.

They are also known as transgenic – have new DNA. Introducing recombinant plasmids into bacterial cells is called transformation. This is done by mixing the plasmids with the cells in a medium containing calcium ions. The calcium ions make the bacterial cells permeable, allowing the plasmids to pass through, into the cell. However, only a few bacterial cells (approx 1%) will actually take up the plasmids. For this reason, we need to identify which ones have been successful. This is done with gene markers. Calcium ion medium Bacteria that do take up recombinant plasmids are now known as transformed bacteria. They are also known as transgenic – have new DNA.

conjugation

Use the top of page 177 to find out: The name of the MRSA species. Conjugation Bacteria can pass genetic material between each other in a process called conjugation. Even different species are capable of transferring plasmids for resistance to antibiotics. This is a concern as resistant strains such as MRSA are spreading in hospitals. Use the top of page 177 to find out: The name of the MRSA species. How MRSA spreads. What is being done to combat the spread of MRSA

How conjugation happens.

plenary Answer questions 1 & 2 on page 177.

learning objectives Understand why scientist genetically engineer organisms. Understand how recombinant plasmids are made. Understand how transgenic bacteria can be made. Understand how bacteria copy and transfer plasmids between each other.

success criteria State reasons why scientists genetically engineer organisms. Describe the steps involved in genetically engineering bacteria. Explain why conjugation in bacteria can lead to concerns in the healthcare sector.