Natural Selection & GM Flashcards
What type of enzyme is used to cut the wanted gene from an organism’s chromosome?
restriction endonuclease (enzyme)
Restriction enzymes can be used to cut open the vector DNA and cut out the desired gene. What is important about these restriction enzymes?
Must use the same restriction enzyme on both DNA strands (so you get complementary sticky ends)
What enzyme is used to join together the vector DNA and the new gene?
ligase enzyme
What are possible vectors for inserting recombinant DNA into organisms?
bacteria - plasmid
plants - virus (or bacteria with a recombinant plasmid)
animals - virus or gene gun
Why will an organism be able to produce a protein coded for by the DNA of a different organism?
DNA code is universal (same in all organisms)
Give three examples of uses of genetic engineering
Bacteria producing human proteins, e.g. insulin
GM animals, producing human proteins in milk (e.g. antibodies)
GM crops, e.g. resistant to specific insects, resistant to drought or with added nutrients
What do we call a genetically modified organism?
transgenic organisms
What are the benefits of genetically modifying crop plants?
increased yield of crop - can grow in new environments (e.g. very dry, wet or cold), plant has a higher growth rate, or resistant to insects so less damage
crop has higher nutritional value, e.g. increased vitamin A production in rice
Fewer herbicides and pesticides used on crop, so less impact on food chains
What are the risks of genetically modifying crop plants?
transfer of gene to wild species, modifying their growth
loss of food supply for an insect may affect food chains
GM crops may outcompete wild species
Expensive to produce, so may not benefit farmers in poorer countries
Why is there always variation in a population of organisms?
mutations take place randomly and continuously
Describe the process of natural selection
Variation in population due to mutation
Some individuals have features making it easier for them to survive (better adapted)
Those individuals who survive reproduce
Pass on alleles for beneficial characteristic to offspring
Characteristic becomes more common
Why will only some organisms in a population reproduce?
only some survive - those with the features which make it easiest to obtain food & a mate (best adapted)
Why are antibiotic resistant bacteria becoming more common?
Mutations happen at random - some bacteria are resistant to antibiotics
Antibiotics used more often - kill the non-resistant bacteria
Less competition, so resistant bacteria multiply and spread
