Exam Questions

Question 1

What is one difference between somatic and germ line therapy?

Answer 1

-somatic targets specific tissues in need of treatment
-germ line cannot

Question 2

Define the term DNA sequencing

Answer 2

-working out the sequence of bases
-mapping out an individuals genome

Question 3

Explain how DNA sequencing allows the sequence of amino acids in a polypeptide to be predicted

Answer 3

-order of bases codes for amino acids
-each triplet codes for 1 amino acid

Question 4

How can DNA sequencing and bioinformatics be used to increase the effectiveness of a vaccination programme?

Answer 4

sequencing
-predict the strain
-ensure vaccines contain the correct antigen

bioinformatics
-access to large amounts of data
-identify the source of the outbreak

Question 5

How can bioinformatics be used in determining whether a newly sequenced allele causes a genetic disease?

Answer 5

-amino acid sequences held in the database
-rapid comparison of sequences with newly sequenced allele

Question 6

Explain why booster vaccinations are needed

Answer 6

-memory cells reduce in number

Question 7

Explain why only selected sections of non-coding DNA are used when profiling a human

Answer 7

-99% of introns are the same across humans
-non-coding contains repeating sequences
-in the telomeres + centromeres
-need to select the sections that are only unique to that individual

Question 8

What is the name of the enzyme used in PCR to synthesis new DNA strands?

Answer 8

-Taq DNA polymerase

Question 9

Describe 3 differences in the process of chromatography and electrophoresis

Answer 9

1. electrophoresis uses electrical charge to separate fragments
2. chromatography separates by solubility
3. buffer solution is used in electrophoresis

Question 10

Describe a process scientists could used to produce pest-resistant vegetables (6 marks)

Answer 10

-insertion of DNA fragment into the DNA of another organism using host or vector cells
1. remove desired gene from the vegetable
2. restrictive endonuclease cut DNA at staggered ends = sticky ends
3. plasmid vector is removed from bacterium containing 2 marker genes
4. sticky ends inserted into vector = recombinant plasmid
5. inserted back into bacterium producing transgenic bacterium which is now pest resistant

Question 11

What events take place when sticky ends are instead into the vector?

Answer 11

-complementary bases pair
-formation of PD bonds
-forming recombinant plasmid

Question 12

State 1 valid concern that people have about the genetic modification of bacteria

Answer 12

-resistance

Question 13

Explain how inserting a new gene into a chromosome could affect the functioning of other genes in that chromosome

Answer 13

-frameshift
-altered triplets
-nearby genes switched on and off