Bacteriophage Lambda

Question 1

Explain what bacteriophages are and name their minimal functions (4):

Answer 1

– Protection of nucleic acid
– Delivery of nucleic acid
– Conversion of infected cell to produce phage
– Release of phage

Question 2

Lytic growth- name 4 stages and briefly explain them

Answer 2

1. Infection:
   phage attaches to bacterium
   DNA (uncoated!) injected into bacterium
2. Early development:
   Enzymes for DNA synthesis are made
   Replication begins
3. Late development:
   Genomes, heads and tails are made
   DNA packaged into heads, tails attached
4. Lysis:
   Cell is broken to release progeny phages

Question 3

Explain the lysogeny and induction

Answer 3

In lysogeny, Phage DNA is integrated into bacterial genome, bacteria live.

Lysogenic bacterium is immune to further infection (INDUCTION)
Phage DNA is released and enters lytic cycle