Question 18M.2.SL.TZ2.6c
| Date | May 2018 | Marks available | [Maximum mark: 8] | Reference code | 18M.2.SL.TZ2.6c |
| Level | SL | Paper | 2 | Time zone | TZ2 |
| Command term | Explain | Question number | c | Adapted from | N/A |
Although simple in structure, bacteria as a group show a wide range of diversity.
Explain the process of genetically modifying bacteria.
[8]
a. genetic modification carried out by gene transfer between species
b. genes transferred from one organism to another produce the same protein/amino acid sequence
c. due to universality of genetic code
OR
organisms use same codons of mRNA to code for specific amino acids
d. mRNA for required gene extracted/identified
e. DNA copies of mRNA made using reverse transcriptase
f. PCR used (to amplify DNA to be transferred)
g. genes/DNA transferred from one species to another using a vector
h. plasmid acts as vector to transfer genes to bacteria/E. coli
i. plasmid cut open at specific base sequences using restriction endonuclease
OR
plasmid cut to produce blunt ends then extra cytosine/C nucleotides added
OR
sticky ends made by adding extra guanine/G nucleotides
OR
mention of sticky ends if not gained already
j. cut plasmids mixed with DNA copies stick together (due to complementary base pairing)
k. DNA ligase makes sugar-phosphate bonds to link nucleotides of gene with those of plasmid
l. bacteria that take up plasmid are identified
m. (genetically modified) bacteria will reproduce carrying the transferred gene
n. example – eg: as production of human insulin using E. coli bacteria
Accept any of the points clearly explained in an annotated diagram.
