Chapter 21 - Recombinant DNA technology

Question 1

Why does the polymerase chain reaction require DNA fragments?

Answer 1

They are to be copied

Question 2

What is DNA polymerase?

Answer 2

Joins together nucleotides

Question 3

What are primers?

Answer 3

Nucleotide sequences that have a set of bases complementary to those at each end of the DNA fragment

Question 4

What is a thermocycler?

Answer 4

Machine that maintains constant temperature

Question 5

Describe the process of the polymerase chain reaction?

Answer 5

DNA fragments, primers and DNA polymerase are added to thermocycler
Temperature increased to 95c
Hydrogen bonds break so two DNA strands separate
Cooled to 55c
Primers join to complementary sections of DNA
DNA polymerase begins replication
Temperature increased to 72c
Transcription occurs
Temperature cycle continues

Question 6

Advantages of in vitro cloning

Answer 6

Very quick

Doesn’t require living cells

Question 7

Advantages of in vitro cloning

Answer 7

Useful to introduce a gene into another organism
No risk of contamination 
Very accurate
Cuts out specific genes
Produces transformed bacteria