21.1 Dna Profiling

Question 1

What are exons

Answer 1

Dna that codes for proteins

Question 2

What are introns

Answer 2

Non coding regions of dna

Question 3

What is satellite dna

Answer 3

Short sequences of dna that are repeated many times

Question 4

What is dna profiling

Answer 4

Producing an image of the patterns in the dna of an individual

Question 5

What is the first stage of producing a dna profile

Answer 5

Extract the dna from a tissue sample

By using polymerase chain reaction

Question 6

What do you do after you extract the dna using polymerase chain reaction in dna profiling

Answer 6

Digest the sample
Strands of dna are cut into small fragments using restriction endonucleases
They cut at specific restriction sites

Question 7

What do restriction endonucleases do

Answer 7

Make 2 cuts at specific restriction sites once through each strand of the dna double helix

Question 8

What happens after you digest the sample

Answer 8

You separate the dna fragments via electrophoresis

Question 9

What is electrophoresis

Answer 9

At technique that utilises the way charger particles move through a gel medium under the influence of an electric current
It’s immersed into alkali to spectate the double strands into single strands and these are transferred onto a membrane for southern blotting

Question 10

What happens after you spreads dna fragments in dna profiling

Answer 10

Hybridisation
Radioactive or fluorescent dna probes are now added in excess to dna fragments
The probes identify the microsatellite regions that are more varied than larger microsatellite regions

Question 11

What are dna probes and what do they do

Answer 11

Are short dna or rna sequences complementary to a known DNA sequence
They bind to complementary strands of dna under particular conditions

Question 12

What is the final step of dna profiling

Answer 12

The dna fragments give a pattern of bars which is the dna profile and it’s unique to every individual

Question 13

What’s the difference between radioactive labels and flourescent labels added to dna probes

Answer 13

If Fluorescent labels are added the meme fans is placed under UV light so the fluorescent tags glow
If radioactive labels were added X-ray images are taken

Question 14

What is polymerase chain reaction

Answer 14

Replicates dna and allows scientists to produce a lot of dna from the tiniest original sample

Question 15

What is teh first stage of pcr

Answer 15

Separate the strand
Temperature in pcr machine is 90-95 for 30 seconds
This denatures the dna by breaking the hydrogen bonds holding the dna strands together

Question 16

What happens after the strands are separated in pcr

Answer 16

Annealing of the primers
Temperature is decreased to 55-60
The primers bind to the ends of the dna strands because they are needed for replication of teh strands to occur

Question 17

What is the last step do pcr after annealing has happened

Answer 17

Temp is increased to 72-75 for at least 1 min, this is the optimum temp for DNA polymerase to work at
DNA polymerase add bases to the primers and build up complemtary strands of dna and produced double stranded dna identical to original sequence

Question 18

What is dna profiling used for

Answer 18

Forensic science
Prove paternity of children
Identify individuals who are at risk of developing partcikar diseases