PCR, gel electrophoresis and DNA profiling

Question 1

polymerase chain reaction

Answer 1

technique used by scientists that amplifies the amount of DNA present exponentially to create millions of identical copies of the DNA from a small sample

Question 2

what’s needs for PCR

Answer 2

• DNA sample
• primers
• free nucleotides
• taq polymerase
• buffer solution

Question 3

DNA sample

Answer 3

provides the target sequence of DNA that is to be copied (or amplified)

Question 4

Primers

Answer 4

short nucleic acid sequences that provide a starting point for DNA to be built on

Question 5

• Free nucleotides

Answer 5

added to solution in order for DNA to be built

Question 6

Taq polymerase

Answer 6

binds to the primer and begins building DNA from the free nucleotides

Question 7

Buffer solution

Answer 7

provides a suitable chemical environment for activity of polymerase

Question 8

PCR consists of three steps

Answer 8

• 1. Denaturation
• 2. Annealing
• 3. Extension

Question 9

Denaturation

Answer 9

The sample is heated to 95° C to break the hydrogen bonds between the two strands of double stranded DNA, to obtain single strands of DNA

Question 10

Annealing

Answer 10

temperature is reduced to 50-60°C. This allows the primers to anneal/bind to complementary sequences on opposite strands at each end of the target DNA sequence.

Question 11

Extension

Answer 11

The temperature is increased to 72°C. This allows Taq polymerase to attach to the primers on the DNA strands. The Taq polymerase moves along each strand adding free nucleotides to form double stranded DNA

Question 12

Gel electrophoresis

Answer 12

technique that separates fragments of negatively charged DNA by length.

Question 13

DNA profiling

Answer 13

identifies one individual from another individual