PetriKey

Concept

Bacterial growth curve

Four phases of a batch culture

bak-TEER-ee-ul groath kurv

growthmetabolismculturekinetics

High-yield clue

The four phases are lag, log (exponential), stationary, and death; drugs targeting cell walls act best during log-phase growth.

Overview

The plot of viable bacterial numbers over time in a closed (batch) culture, showing four phases: lag, log (exponential), stationary, and death. It is the core model for understanding population growth and antibiotic timing concepts.

Classification

  • Batch-culture model
  • Lag phase (adaptation)
  • Log/exponential phase
  • Stationary then death phase

Lab & identification clues

  • Generation/doubling-time vocabulary
  • Viable-count vs turbidity concept
  • Stationary-phase nutrient-limitation vocabulary

Associations

  • Endospore formation in stationary phase
  • Log-phase susceptibility to cell-wall agents
  • Nutrient depletion and waste buildup

Commonly confused with

  • Continuous (chemostat) culture
  • Death-phase vs stationary-phase

Your notes

Original microbiology concept summary. Sources checked: OpenStax Microbiology 2e, NCBI Bookshelf Medical Microbiology, and CDC/WHO topic pages where applicable; reviewed 2026-06. Educational only; no diagnosis, treatment selection, infection-control instructions, or specimen-handling guidance.

OpenStax: Microbiology 2e concept foundationssourceNCBI Bookshelf: Medical Microbiology general conceptssourceCDC: CDC public-health concept pagessource