Phage lambda cro repressor system

What protein concentration determines lytic cycle?

low cII

What protein concentration determines lysogenic cycle?

high cII

activates the lytic phase of phage development in infected E. coli cells by suppressing the activity of transcriptional terminators that prevent the synthesis of essential phage proteins.

N

Phage plaque that appears turbid indicates

lysogenic pathway (due to production of lysogens)

bacterium that carries phage DNA (a prophage) integrated into its genome.

lysogen

number of infecting phages per cell

multiplicity of infection

High multiplicity of infection (MOI) stimulates

lysogeny

Low multiplicity of infection (MOI) stimulates

lysis

recombination genes in bacteriophage lambda

int, xis, att

DNA replication genes in bacteriophage lambda

Q

causes RNA polymerase to ignore termination signal and continue elongating transcript until second signal reached.

anti-termination factor

Repressor protein that represses gene encoding DNA repair enzymes.

LexA

Stimulates autocleavage of lambda repressor.

RecA

RecA leads to lytic or lysogenic growth?

lytic