4 Natural Selection & Genetic Modificaion Flashcards
What is selective breeding?
Humans choose animals & crops to breed
- based on genetic characteristics
What is selective breeding also known as?
Artificial selection
What are the reasons for selective breeding?
Usefulness
Appearance
What are examples of things that are selectively bred?
- dogs
- crops
- flowers
- animals
Problems with selective breeding:
Interbreeding
- e.g. french bulldogs have flat faces, causes severe breathing problems
- Susceptible to disease / inherited defects
Reduced variation
- makes species harder to adapt to environmental change
What involves growing genetically identical cells in a lab under sterile conditions (without contamination from microorganisms)?
Tissue culture
What is tissue culture process?
- tissue sample taken from plant
- cells sterilised
- sample treated with hormones to trigger cell division, grown on agar plate
- ball of cells (callus) forms + more hormones cause roots & stems to grow
- plants can be planted in soil
What is an agar plate?
Plant food in jelly form
What is the first stage of tissue culture?
Taking cuttings from plants
Why do tissue culture?
Plants
- produce lots of genetically identical plants quickly
- any time of yer
- genetic modifications quickly
- increase population numbers of rare plant
Medicine
- study cell processes
- drug effectiveness
- study viruses that cannot survive outside of cells
- grow artificial tissues
What is genetic engineering?
Modifying an organisms genome by introducing another gene from another organism to produce a desired characteristic
What are examples of genetic engineering?
Vitamin A rice
- lack of vitamin A can lead to blindness
Insulin producing gene
- inserted into bacteria
- bacteria mass produce it
What is the first stage of genetic engineering?
Cut target gene out
- retraction enzymes used to ‘cut’ a desired gene out of a chromosome
What is the second stage of genetic engineering?
Cut a vector
- restriction enzyme used to ‘cut’ a vector
- target gene & vector have exposed single- stranded DNA (sticky ends)
- vector usually bacterial plasmid/ virus
What is the 3rd stage of genetic engineering?
Gene inserted
- enzyme (ligase) used to join sticky ends
- vector now carries target gene
- marker gene (e.g. antibiotic resistance gene) added to make easy to check vector taken up target gene
