manipulating genomes

Question 1

genome

Answer 1

all the genetic material an organism contains

Question 2

introns

Answer 2

large non coding regions of DNA that are removed from mRNA before it is translated into a polypeptide chain

Question 3

extrons

Answer 3

regions of DNA that do code for proteins

Question 4

satellite DNA

Answer 4

short sequences of DNA within introns that are repeated many times

Question 5

minisatellite

Answer 5

a sequence of 20-50 base pairs which is repeated 50 to several hundred times

Question 6

microsatellite

Answer 6

a sequence of 2-4 bases only repeated 5-15 times

Question 7

producing a DNA profile

the five main stages

Answer 7

extracting the DNA 
digesting the sample 
separating  the DNA fragments 
hybridisation 
seeing the evidence

Question 8

producing a DNA profile

extracting the DNA

Answer 8

polymerase chain reaction is used to get DNA from the tiniest fragment of tissue

Question 9

producing DNA profile

digesting the sample

Answer 9

strands of DNA cut into small fragments using restriction endonucleases which cut the DNA at recognition sites.

Question 10

producing a DNA profile

separating the DNA fragments

Answer 10

electrophoresis is used
fragments of different sizes move at different speed through the jel and then the jel is immersed in alkali to separate the DNA double strands into single strands which are then transferred onto membrane

Question 11

producing a DNA profile

hybridisation

Answer 11

fluorescent DNA probes added, they are short DNA sequeces complementary to known DNA sequence they bind to complementary strands of DNA

Question 12

producing a DNA profile

seeing the evidence

Answer 12

membrane placed under UV light so the flourescent tags glow. fragments give a pattern of bars which is unique to every individual

Question 13

electrophoresis

Answer 13

DNA fragments put into agarose gel
electric current flows through towards positive end due to negative phosphate groups in DNA, rate of movement depends on length smaller move easier and so move further

Question 14

polymerase chain reaction

Answer 14

90°C for 30 seconds to denature the DNA by breaking hydrogen bonds causing them to separate
60°C primer anneal to end of DNA
75°C for at least a minute, optimum for DNA polymerase to work which adds bases to the primer producing identical double strands of DNA. taq polymerase used