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

Question 4

scientists have produced a variety of aubergine that is resistant to moth larvae by tranferring a gene from the bacillius bacterium

describe the process the scientists could have used to produce the pest-resistant aubergines

Answer 4

-method of gene extraction from bacterium e.g with restriction enzymes
-use of vector
-electroporation
-dna ligase
-marker genes, identification

Question 5

how can large quantities of bacteria, animals, plants b grown

Answer 5

bacteria grown in fermenters
animals bred on pharms
plants grown in licensed fields