Phage

Question 1

What are bacteriophage?

Answer 1

viruses that infect bacteria

Question 2

What do viruses need to replicate?

Answer 2

a host

Question 3

What is the structure of a virus?

Answer 3

Nucleic acid core: RNA or DNA
Capsid: protein coat
Enveloped (some)

Question 4

Lytic Cycle

Answer 4

cell dies

Question 5

Lysogenic cycle

Answer 5

Cell lives

Question 6

Life cycle of T-even Phage

Answer 6

1. attachment: tail fibers of the phage attach to receptors on the bacteria
2. penetration: lysozyme are released to degrade the cell
   - contraction of viral sheath, drive the phage core into cell wall, DNA goes into host
3. Biosynthesis: uses the host nucleotides and enzymes to transcribe and translate viral proteins and DNA
4. Maturation: DNA and capsids are assembled together
5. Release: release viruses from the host (lysozyme leads to bacterial cell lysis)

Question 7

How to quantify viruses in a sample

Answer 7

-Must provide a host (lawn of Escherichia coli B)

• When the cells are infected with a virus, virus will lyse the cells causing plaques
• Plaques are quantifiable and we can calculate PFU/mL