genetic revolution 5.12, 5.13, 5.14, 5.15, 5.16, 5.17B, 5.18B, 5.19B, 5.20B

Question 1

what are transgenic organisms?

Answer 1

organisms which have received genes from another species

Question 2

what can be used to carry the dna from one organism to another?

Answer 2

vectors
for example, a vector has been used to introduce foreign DNA into bacterial cells is the bacteriophage (a type of virus)
the bacteriophage attacks a bacterium by injecting its own dna into the bacterial cell
the dna becomes incorporated into the dna of the host cell and eventually causes the production of many virus particles
another example involves cutting genes from human chromosomes and inserting them into the plasmid of a bacterium

Question 3

what are plasmids?

Answer 3

bacteria have small, circular pieces of DNA

Question 4

how do you genetically engineer?
example of diabetes

Answer 4

• first the human insulin gene must be located on the chromosome
• the gene is then cut from the rest of the chromosome using a DNA restrictive enzyme
• a plasmid is removed from the bacterium and cut open with the same DNA restrictive enzyme
• each DNA restrictive enzyme cuts at a specific sequence of bases, producing short single stranded sections called sticky ends
• the human insulin gene and plasmid join together due to complementary base pairing at the stinky ends, a DNA ligase enzyme forms bonds between the nucleotides to make this a single piece of DNA
  = we say the plasmid is now recombinant DNA

Question 5

manufacturing genetically modified products from bacteria:

Answer 5

• transgenic bacteria are then placed into a fermenter in order to increase in number
• this is sterilised prior to use
• the insulin is secreted by the bacteria then collected from the fermenter, purified and distributed

Question 6

genetic modification in crops:

Answer 6

• introducing the new gene or genes into plant cells
• producing whole plants from just a few cells

Question 7

advantages of genetic modification in crops:

Answer 7

• more precise than selective breeding
• higher crop yield/ better food quality
• less pesticide/ herbicide used so less pollution
• disease resistant

Question 8

disadvantages of genetic modification in crops:

Answer 8

• not accepted by public
• long term affects unknown
• may affect food chains/ environment
• reduces variation

Question 9

what is micro-propagation?

Answer 9

method of producing much larger numbers of genetically identical plants
complex and requires labs equipment

Question 10

what is the method of micro-propagation?

Answer 10

• stage 1 is to take a small section (explant) cut from desired plant
• it is sterilised and placed onto a nutrient gel where it grows into a small ball of cells (callus)
• small groups of cells are then taken from the callus and enters next stages
• plant hormones are used to stimulate shoot and root growth
• these small bundles of cells grow into individual cloned plants

Question 10

how to clone mammals?

Answer 10

• a dna is extracted with a whole nucleus
• electric shock used to fuse the nucleus and empty (enucleated) egg cell = stimulating mitosis

Question 11

why can cloning mammals be a huge advantage?

Answer 11

• clone animals with desirable characteristics
• save species that are close to extinction