12. Gene Regulation in Prokaryotes

In which of the following life cycles does a bacteriophage integrate itself into the host genome?

In good growth conditions the bacteriophage is more likely to enter into which life cycle?

Activation of which of the following genes leads to entrance into the lysogenic cycle?

The N protein is an anti-terminator. What does this mean?

Which of the following proteins is mainly responsible for entering the bacteriophage into the lysogenic cycle?

Describe the difference between the bacteriophage lytic cycle and lysogenic cycle.

Describe the lytic and lysogenic life cycles of λ bacteriophage. What roles do λ repressor and Cro protein play in controlling transcription from P_R and P_RM, and how are these roles linked to lysis and lysogeny?

Suppose that base substitution mutations sufficient to eliminate the function of the operator regions listed below were to occur. For each case, describe how transcription or life cycle would be affected.

O_R1 mutation in λ phage

Suppose that base substitution mutations sufficient to eliminate the function of the operator regions listed below were to occur. For each case, describe how transcription or life cycle would be affected.

O_R3 mutation in λ phage

Two different mutations affect P_RE. Mutant 1 decreases transcription from the promoter to 10% of normal. Mutant 2 increases transcription from the promoter to 10 times greater than the wild type. How will each mutation affect the determination of the lytic or lysogenic life cycle in mutant λ phage strains? Explain your answers.

How would mutations that inactivate each of the following genes affect the determination of the lytic or lysogenic life cycle in mutated λ phage strains? Explain your answers.

N

How would mutations that inactivate each of the following genes affect the determination of the lytic or lysogenic life cycle in mutated λ phage strains? Explain your answers.

cII and cro

How would mutations that inactivate each of the following genes affect the determination of the lytic or lysogenic life cycle in mutated λ phage strains? Explain your answers.

int

How would mutations that inactivate each of the following genes affect the determination of the lytic or lysogenic life cycle in mutated λ phage strains? Explain your answers.

cro

How would mutations that inactivate each of the following genes affect the determination of the lytic or lysogenic life cycle in mutated λ phage strains? Explain your answers.

cI