Lab: Genetic Exchange

Question 0

Conjugation

Answer 0

Allows genetic exchange to occur between two bacterial cells in direct contact with one another and form a sex pilus

Question 1

Three mechanisms of genetic exchange amongst bacteria

Answer 1

• transformation
• transduction
• conjugation

Question 2

Plasmid

Answer 2

Circular pieces of dsDNA that exist and replicate independently of chromosomal DNA

Transferred from F+ donor to F- recipient

Contains F factor ( allows plamsmid to be integrated)

Question 3

Bacterial transformation

Answer 3

Microorganism takes up naked DNA from it’s environment

Question 4

Organisms that undergo transformation are considered

Answer 4

Competent

Question 5

Natural transformation

Answer 5

Organisms have membrane-bound proteins that actively transport DNA into the cell

Question 6

Artificial transformation

Answer 6

• electroporation: electric current applied and causes pored to be generated in cellular membrane allowing DNA to enter cell
• heat-shock in calcium chloride: causes membrane to become permeable to DNA

Question 7

Selecting for transformed bacteria

Answer 7

Use marker proteins that give a selective advantage to the orgs with transformed gene and allows it to be distinguished

Question 8

Transduction

Answer 8

Viral phage or bacteriophage infects and transfers genetic material to a bacterial cell.

Question 9

Components of viral phage

Answer 9

• head (containing genetic material - DNA, RNA, both)
• neck extending from head
• collar that sits on top of sheath
• base plate at the end of the sheath
• protein syringe hidden and protected in the sheath above the base plate
• tail fibers extending from the sheath

Question 10

Attachment steps in transduction

Answer 10

• one of the tail fibers attaches to the host cell creating a lock and key connection
• all other fibers then orient themselves to attach to the host cell locking phage onto bacteria
• penetration begins
• once fibers attached, conformational change, base plate pushes sheath up over neck exposing protein syringe that penetrates bacterial cell
• genetic material delivered into cell

Question 11

Vertical gene transfer

Answer 11

passed down through generations

Question 12

Horizontal gene transfer

Answer 12

transferred from an unrelated bacterium

transformation, conjugation, transduction

Question 13

F factor

Answer 13

• segment of plasmid
• when expressed sex pilus forms
• contains gene that allows for chromosomal integration
  must be present for conjugation to occur