exam Q's

Question 1

Explain why the polymerase chain reaction was used on the sample of DNA from the toothbrush

Answer 1

toothbrush gives small sample of DNA/ need more DNA for analysis; PCR gives many copies

Question 2

Explain one way in which the polymerase chain reaction differs from DNA replication in a cell

Answer 2

-uses heat; to separate strands
-primer added in PCR; to initiate replication

Question 3

Tests for use in criminal cases often take much longer because samples are very small or contaminated (lines 8-10). Explain why it takes longer to obtain a genetic fingerprint if the sample is
-very small
-contaminated

Answer 3

-very small= PCR/amplification needed
- contaminated= other DNA present; need to identify ‘required’ DNA from rest