CHAPTER 8 RECOMBINANT DNA

Bacteria which do not have restriction enzymes cannot...

• protect themselves from viruses.

• replicate their plasmids.

• be used as vectors in gene cloning.

• be used as host cells in gene cloning.

• The bacteria multiply but the plasmid cannot replicate in the bacteria.

• The bacteria cannot survive at all.

• The bacteria multiply but cannot express the foreign gene carried by the plasmid.

• The bacteria survive but cannot be cloned.

What is enzyme X?

• DNA polymerase

• RNA polymerase

• DNA helicase

• DNA ligase

Rearrange the following steps in the correct sequence.

I. Cut the plasmid and human DNA with same restriction enzyme.

II. Screen for the bacteria that contains recombinant DNA.

III. Insert DNA fragment into the cut bacterial plasmid.

IV. Isolate the bacterial plasmid and human DNA.

V. Transformation and amplification

• I,II,III,IV,V

• I,IV,III,V,I

• IV,I,III,V,II

• IV,I,III,II,V

• The gene of interest can be found in colonies 1, 3 and 4.

• Colonies 2 and 5 carry recombinant plasmids with intact lacZ genes.

• Only colonies 2 and 5 were able to survive in the antibiotic medium.

• All colonies contain transformed and non-transformed bacteria.

What is the purpose of amplification?

• To screen for recombinant bacterial cell.

• To join the DNA fragment with the cut plasmid.

• To produce multiple copies of the desired gene.

• To prevent the bacteria from reproducing.

• A

• B

• C

• D

If two double-stranded DNA molecules are used at the beginning of a polymerase chain reaction(PCR), how many double-stranded DNA molecules can be obtained after two cycles?

• 2

• 4

• 8

• 32

• 1

• 2

• 3

• 4

Which if the following is true about cDNA?

• They are usually single-stranded DNA.

• They contain both introns and exons.

• They are composed of DNA fragments synthesised with the use of RNA polymerase.

• They contain DNA fragments complementary to mRNA.