M6 C21 Manipulating genomes

Question 1

what is a genome?

Answer 1

minimum genetic material that contains 1 copy of all genes of an individual

Question 2

what is gene technology?

Answer 2

the manipulation of an organisms dna to produce an organism or product

Question 3

what are autosomes?

Answer 3

chromosomes that aren’t sex chromosomes

Question 4

what are non coding regions of DNA called?

Answer 4

introns

Question 5

what are the 5 stops of producing a DNA profile?

Answer 5

extraction
digestion
seperation
hybridisation
development

Question 6

what happens in extraction?

Answer 6

DNA is extracted in PCR

Question 7

what does PCR stand for?

Answer 7

polymerase chain reaction

Question 8

what happens in step 1 of PCR?

Answer 8

excess nucleotide bases are put into the tube woth the DNA that we want to copy and primers. this is then heated up to denature the hydrogen bonds between bases to seperate the DNA

Question 9

What temperature is used in step 1 of PCR?

Answer 9

95 degrees

Question 10

what happens in step 2 of PCR?

Answer 10

primers are added to each separate strand, they signal where the DNA should start and end replicating.

Question 11

what temperature is used in step 2 of PCR?

Answer 11

65 degrees

Question 12

what happens in step 3 of PCR?

Answer 12

the extension of DNA as 2 taq polymerase molecules attach to the 2 primers on the 2 DNA strands. they move along the new strand as free nucleotides bind to the complementary bases.

Question 13

what temperature is used in step 3 of PCR?

Answer 13

72-75 degrees as this is the optimum temperature of taq polymerase

Question 14

what happens after the extraction of DNA?

Answer 14

digestion

Question 15

what happens in digestion?

Answer 15

the strands of DNA are cut into small fragments by restriction enzymes at different points

Question 16

what happens in seperation?

Answer 16

the fragments are then separated by gel electrophorisis

Question 17

what happens in gel electrophoresis?

Answer 17

they seperate the fragments by legnth as the negative backbone is attracted to the positive elctrode at the end of the agar gel as an electric current is put through the gel

Question 18

what size fragments move quicker in gel electrophoresis?

Answer 18

smaller fragments

Question 19

what happens in hybridization?

Answer 19

radioactive or fluorescent DNA probes are added in excess to the fragments. they bind to the DNA strands separated in the gel and the excess is washed off

Question 20

what happens after hybridization?

Answer 20

development of the evidence as the membrane with the dna evidence is put onto a x-ray film which reveals the dark bands where the dna is/ where probes have attached

Question 21

what can DNA profiling be used for?

Answer 21

crime scene analysis
paternity tests
immigration relationships
see how at risk someone is for a particular disease

Question 22

what is sanger sequencing?

Answer 22

radioactive labelling of bases

Question 23

what is added in sanger sequencing?

Answer 23

DNA for sequencing is mixed with a primer, DNA polymerase, free nucleotides, terminator nucleotides

Question 24

what happens in sanger sequencing?

Answer 24

heated at 96 degress to seperate the strands
cooled to 50 degrees to anneal the primers
heated agasin to 60 degrees so polymerase can create new strand by adding complementary bases

Question 25

what happens when a terminator base is added instead of a ‘normal’ base?

Answer 25

the synthesis of dna is terminated as no more nucleotides can join
as there is a lower amnount of terminators compared to the nucleotides lots of different lenghts of fragments are produced.

Question 26

what happens after many cycles of Sanger sequencing?

Answer 26

all the possible dna chains will have been produced. they are then seperated by length in capillary sequencing which works like gel lectrophoresis

Question 27

what detects the final base on each fragment of DNA?

Answer 27

fluorescent markers on the terminator bases at the end of each sequence

Question 28

how are the final bases recognized when sequencing DNA?

Answer 28

Lasers detect the different bases as they all have different fluorescent colors for each 4 bases this is then fed into a computer to sequence a genome