Phage one-step growth curve: the interval during which extracellular phage titer rises to a plateau is called what?

Difficulty: Easy

Correct Answer: rise period

Explanation:


Introduction / Context:
The one-step growth experiment dissects phage replication into characteristic stages by plotting extracellular phage count over time. Correct terminology helps interpret curves and quantify kinetics. The item asks for the term describing the phase when extracellular titer increases and then reaches a constant level.



Given Data / Assumptions:

  • Multiplicity of infection is controlled to synchronize infection.
  • Phage adsorption is rapid, followed by intracellular replication.
  • Sampling measures extracellular infectious particles at fixed intervals.


Concept / Approach:
After the eclipse period (no detectable mature intracellular phage), lysis begins and infectious particles are released into the medium. The rise period is the interval during which extracellular titer increases rapidly. When lysis completes across the population, the curve approaches a plateau. The latent period spans adsorption to the first appearance of extracellular phage and includes the eclipse period; it is not the rising interval itself. “Burst size” is a yield, not a time period.



Step-by-Step Solution:

Map phases: adsorption → eclipse → onset of lysis → rise → plateau.Identify the requested phenomenon: extracellular titer increases to a constant level.Match to terminology: “rise period.”Exclude latent period (earlier, before extracellular appearance) and burst size (a number, not a time).


Verification / Alternative check:
Classic Delbrück–Luria phage growth curves illustrate these intervals and definitions.



Why Other Options Are Wrong:

  • Eclipse period: No detectable mature phage; occurs earlier.
  • Latent period: Ends at first extracellular detection; not the rising interval.
  • Burst size: A yield per cell, not a time interval.


Common Pitfalls:
Mixing up latent and rise periods; treating “burst size” as a temporal metric.



Final Answer:
rise period

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