7.1.1 Biotechnology: Plasmids in Prokaryotes

Question 1

biotechnology

Answer 1

• the utilization of organisms and their components to perform functional tasks in research and to make
  products that are useful to humans

Question 2

plasmids

Answer 2

• small circular pieces of DNA that are separate from the bacterial chromosome and can carry genes that encode proteins with specific functions
• circular pieces of DNA that are separate from
  the bacterial chromosome. Plasmids are self-replicating and have genes that encode proteins with very specific functions
• Some plasmids code for the ability to participate in
  bacterial conjugation. Conjugation is the process by which genetic material is transferred between two bacteria. A plasmid can encode for a bacterium’s ability to form a pilus (pl. pili). A pilus is a structure that connects two bacteria together and allows for the transfer of DNA from one bacterium to the other.

Question 3

Plasmids can code for the following:

Answer 3

· the ability to form pili: Pili are involved in bacterial conjugation.
· antibiotic resistance: Fungi produce chemicals called antibiotics that are able to kill bacteria (a natural competitor). Bacteria that have a resistance plasmid are able to overcome specific antibiotics.
· toxins: Some of the chemicals that bacteria produce can cause a person who has a bacterial infection to be ill. Many of these chemicals are encoded in plasmids.
· protective proteins: Some bacteria have protective protein coats that are encoded in plasmids.

Question 4

R plasmids

i. are plasmids that encode antibiotic resistance.
ii. are plasmids that encode the F factor.
iii. can be transferred through conjugation.
iv. may contain transposons.

Answer 4

• i, iii, iv

Question 5

Which of the following is not a characteristic of plasmids?

Answer 5

• They are found in the cytosol of eukaryotic cells

Question 6

Plasmids are important in bacterial conjugation because

Answer 6

• they code for the proteins necessary for the sex pili.
• they are transferred from one cell to another.
• A and C

Question 7

Plasmids can be used as cloning vectors. Which statement most accurately describes their role as vectors?

Answer 7

• Plasmids carry non-bacterial DNA into bacterial cells where they replicate with the cells

Question 8

Plasmids may encode toxins produced by bacteria. One advantage of having toxin genes on plasmids rather than as part of the genome is that

Answer 8

• multiple copies of the toxin gene can be produced to increase toxin production.