3.5 Genetic modification and biotechnology

Question 1

What does PCR stand for?

Answer 1

Polymerase chain reaction

Question 2

What is PCR?

Answer 2

An artificial method of replicating DNA in lab conditions

Question 3

What is the PCR technique used to do?

Answer 3

Amplify large quantities of a specific sequence of DNA from an initial minute sample

Question 4

What does each cycle of PCR do to the amount of DNA?

Answer 4

Double it

Question 5

Where does PCR occur?

Answer 5

In a thermal cycler

Question 6

What does PCR use to control the replication process?

Answer 6

Variations in temperature

Question 7

What are the three stages of PCR?

Answer 7

Denaturation
Annealing
Elongation

Question 8

What happens during the denaturation stage of PCR?

Answer 8

DNA sample is heated to separate it into two single strands

Question 9

What is the temperature for the denaturation stage of PCR?

Answer 9

95C for 1 min

Question 10

What happens during the annealing stage of PCR?

Answer 10

DNA primers attach to the 3’ ends of the target sequence

Question 11

What is the temperature during the annealing stage of PCR?

Answer 11

55C for 1 min

Question 12

What happens during the elongation stage of PCR?

Answer 12

A heat tolerant DNA polymerase binds to the primer and copies the strand

Question 13

What is the temperature used during the elongation stage of PCR?

Answer 13

72C for 2 min

Question 14

After PCR and once large quantities of DNA have been created what happens?

Answer 14

Other lab techniques are used to isolate and manipulate the sequences

Question 15

What is gel electrophoresis?

Answer 15

A lab technique used to separate and isolate proteins or DNA fragments based on size

Question 16

What happens in gel electrophoresis?

Answer 16

Samples are placed in a block of gel and an electric current is applied which causes the samples to move through the gel

Question 17

Why will smaller samples move faster through the gel in gel electrophoresis?

Answer 17

As they are less impeded by the gel matrix

Question 18

Why do samples of different sizes separate?

Answer 18

As they travel at different speeds

Question 19

How may DNA be cut into fragments?

Answer 19

Using restriction endonuclease

Question 20

What will different DNA samples generate?

Answer 20

Different fragment lengths

Question 21

In DNA separation, why do fragments separate?

Answer 21

Because DNA is negatively charged due to the presence of a phosphate group on each nucleotide

Question 22

In DNA separation, where are DNA samples placed?

Answer 22

Into an agarose gel

Question 23

In DNA separation, how is fragment size calculated?

Answer 23

By comparing against known industry standards

Question 24

In DNA separation how can specific sequences be indentified?

Answer 24

By incorporating a complementary radiolabelled hybridisation probe, transferring the separated sequences to a membrane and then visualising via autoradiography

Question 25

In protein separation, what must proteins first be treated with?

Answer 25

An anionic detergent

Question 26

In protein separation,why must proteins be treated with an anionic detergent?

Answer 26

To linearise and impart a uniform negative charge

Question 27

In protein separation, where are protein samples placed?

Answer 27

In polyacrylamide gel

Question 28

In protein separation, what are sizes compared against?

Answer 28

Known industry standards

Question 29

In protein separation, where are separated proteins transferred to?

Answer 29

A membrane

Question 30

In protein separation, how are target proteins identified?

Answer 30

By staining with specific monoclonal antibodies

Question 31

How can proteins affect size?

Answer 31

They may be folded into a variety of shapes

Question 32

How do proteins have no clear charge?

Answer 32

They have positive and negative regions