MICROBIAL GROWTH Flashcards
Increase in the population of cells is called a
culture
Cell division is by an asexual process called
binary fission
the time it takes to divide
(double) is called
generation time
Organisms are adjusting to the environment
(little or no division).
Lag Phase
They are synthesizing DNA, ribosomes and
enzymes to breakdown nutrients, and to be
used for growth
Lag Phase
Division is at a constant rate (generation time)
but varies with species, temperature and media.
Log or Logarithmic phase
In Logarithmic Phase, cells are most susceptible to
inhibitors
Dying and dividing organisms are at an
equilibrium.
Stationary phase
Stationary phase
Death is due to _______. Cells are
smaller and have fewer ribosomes
reduced nutrients, pH changes,
toxic waste and reduced oxygen
Stationary Phase
In some cases cells do not die but they are not
Multiplying
The population is dying in a geometric fashion
so there are more deaths than new cells.
Death or Decline phase
Deaths are due to the factors in ______in addition to lytic enzymes that are
released when bacteria lyse.
stationary
phase
Population doubles every 20 minutes
Exponential Phase/Log Phase
Factors That Affect Microbial Growth
- Availability of
Nutrients - Moisture
- Temperature
- pH
- Osmotic
Pressure - Barometric
Pressure - Gaseous
Atmosphere
Components of Carbohydrates
C, O, H
Components of Protein
C, O, H, N
Electrolytes include
Na, K, Cl, Mg, Ca, Fe, I, Zn
Other growth factors are organized into three
categories:
Purines and Pyrimidines
Amino Acids
Vitamins
required for
synthesis of nucleic acids (DNA and RNA)
Purines and pyrimidines
Five membered ring:
Six membered ring:
Purine
Pyrimidine
required for the synthesis of
proteins
Amino Acids
Amino acids produced by the body, and do not need exogenous source
Non-essential Amino Acid
Amino Acids which are not produced in the body and are acquired through an external source
Essential Amino Acids
Vitamins: co____
Minerals: co____
enzymes
factors
needed as coenzymes and
functional groups of certain enzymes
Vitamins
(organisms that use
CO2 as a carbon
source)
Autotrophs