Microbiology: Replication Mechanisms and Bacterial Growth Curves

Vocabulary flashcards defining key terminology associated with microbial replication mechanisms, pure culture methods, and the phases of the bacterial growth curve based on the lecture.

Thermophile

Any microbe that thrives or lives in a high-temperature environment, such as boiling hot springs.

Colligative property

A chemical property of solutions where the addition of solutes raises the boiling point and lowers the freezing point of water.

Growth (Microbiology)

An increase in the total number of cells through cell division, rather than an increase in the physical size of individual cells.

Binary fission

A growth mechanism typical of bacteria where a mother cell forms a septum and divides into two daughter cells, resulting in the loss of the original mother cell.

Budding

A growth mechanism typical of yeast where a protrusion forms on a mother cell, enlarges, receives a copy of the genome, and separates without losing the mother cell.

Pure culture

A culture that contains only one type of cell or organism.

Colony

A visible population or mass of cells arising from a single original cell on a solid medium.

Colony Forming Unit (CFU)

A unit and widely used acronym in microbiology representing a viable cell capable of dividing to form a colony on a plate.

Streak plate method

A pure culture isolation technique developed by Robert Koch that uses an inoculation loop to perform a serial dilution of bacteria across sections of an agar plate.

Semilog plot

A graph format combining a linear axis (such as time) with a logarithmic axis (such as cell number) to display exponential data within a reasonable scale.

Lag phase

The initial phase of a bacterial growth curve where cells adapt to their environment and enlarge without undergoing cell division or binary fission.

Log phase

The phase of exponential growth in a bacterial growth curve characterized by rapid, asynchronous binary fission and a logarithmic increase in cell numbers.

Stationary phase

The phase in a bacterial growth curve where the number of dying cells equals the number of new cells formed due to an essential nutrient becoming limiting.

Decline phase

The phase of a bacterial growth curve where the number of live cells decreases logarithmically due to nutrient depletion or the accumulation of toxic waste products.

Asynchronous growth

A pattern of cell division where cells in a population divide at slightly different times rather than simultaneously, producing a smooth exponential curve.