This lesson explains how bacteria commonly reproduce and how their growth rate is described. These ideas help us predict how quickly a microbial population can increase.
Most bacteria reproduce asexually by binary fission. Before division, a cell grows and makes more of its cellular components. DNA replication begins at the chromosome’s origin of replication and proceeds in opposite directions around the chromosome until the replication process reaches the terminus.
All flashcards
Binary fission
Asexual reproduction in which a cell replicates its DNA and divides to produce two daughter cells.
Divisome
The protein complex that coordinates construction of the division septum.
Generation time
The time required for a microbial population to double through one round of binary fission.
Viable plate count
An estimate of living, culturable cells based on the colonies they form on suitable medium.
Biofilm
A structured microbial community associated with a surface and embedded in a self-produced matrix.
Quiz questions
In the log phase of a batch culture, what characterizes population change?Answer: Cells divide actively and the population rises exponentially.
How does a chemostat help sustain microbial growth?Answer: It supplies fresh nutrients and removes culture at a controlled rate.
What does a viable plate count reported in CFU/mL estimate?Answer: The concentration of living, culturable units that form colonies.
As microbial cell density rises, what typically happens to turbidity measured by a spectrophotometer?Answer: Absorbance increases as less light passes through the suspension.
How does quorum sensing link microbial population density to coordinated behavior?Answer: Autoinducers accumulate, bind receptors at a threshold, and alter gene expression.
Based on Microbiology by Nina Parker, Mark Schneegurt, Anh-Hue Thi Tu, Philip Lister, Brian M. Forster (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.