LESSON 9: BACTERIAL GROWTH Flashcards
-refers to the increase in number of cells not the size of cells.
MICROBIAL GROWTH
-bacteria undergo asexual division to produce 2 daughter cell genitically identical to the parent cell.
BINARY FISSION
-the Z-ring is mainly composed of this polymers assemble in the middle of the cell.
FtsZ POLYMERS
-it’s the first step of bacterial cytokines.
Z-RING
-time required for a bacterium to give rise to 2 daughter cells under optimum conditions.
GENERATION TIME
what is generation time o e.coli ?
20min, 7 hours can undergo 20 generations
-bacterial counting can be measured in terms of?
- CELL CONCENTRATION
- BIOMASS CONCENTRATION
-it’s a number of viable cell per unit volume
CELL CONCENTRATION
-dry weight of cell per unit volume.
BIOMASS CONCENTRATION
-it denotes the total number of bacteria whether they are living or deade.
TOTAL COUNT
-total number of living or viable bacteria
VIABLE COUNT
-viable count can be obtained by 2 method:
- DILUTION METHOD
- PLATING METHOD
-series of sequential dilutions used to reduce a dense
culture of cells to a more usable concentrations.
DILUTION METHOD
-number of colonies that grow after a suitable incubation time.
PLATING METHOD
-the time between inoculation and beginning of multiplication is known as?
note: no appreciable increase in number
of bacterial cell in this phase
LAG PHASE
-This phase is characterized by rapid exponential cell growth of bacteria at their maximum rate.
note: the microbes are sensitive to antibiotics & antimicrobial agents
LOG PHASE
- in this phase bacterial growth almost stops
completely due to depletion of essential nutrients.
note: endospores starting to form in this phase.
STAIONARY PHASE
-in this phase, the bacterial population declines due to death of cells due to.
1. AUTOLYTIC ENZYME
2. EXHAUSTION OF NUTRIENTS
DECLINE PHASE
-Is a method utilized for industrial and research purpose that is achieved by using a special device for replenishing nutrients and removing bacterial population continuously so that bacteria growth is not inhibited due to lack of nutrients or due to accumulation of toxic bacterial metabolites
CONTINUES CULTURE
-minimum and maximum temperature are only what?
30 degree celsius
-is the lowest temperature at which a species will grow.
MINIMUM TEMPERATURE
-this temperature is when a species grow best.
OPTIMUM TEMPERATURE
-is the highest temperature at which a species can grow.
MAXIMUM TEMPERATURE
-refers to the alkalinity or acidty of a solution.
pH
-what is the neutral pH
6.5-7.5
-is the pressure required to stop water/solution from
diffusing through a barrier by?
OSMOSIS or OSMOTIC PRESSURE
- by osmosis. Microorganisms require water
for growth and are made of water, how many percentage?
80-90%
-when solution outside the cell has higher concentration of solutes than Inside the cell, water is diffused outside of cell and then the cell will SHRINKS
HYPERTONIC
-When solution outside the cell has lower concentration of
solutes than inside the cell, water is diffused inside of cell and the cell SWELLS
HYPOTONIC
-when concentrations in two solutions are same, so cell
will neither SWELL nor SHRINK
ISOTONIC
-important for all organic compounds that make up a living cell;
-also cosist the half dry weight of bacteria
CARBON
-helps form the amino group in amino acid.
NITROGEN
-used to synthesize sulfur-containing amino acids and vitamins
SULPHUR
-important in synthesis of ATP, nucleic acids and
phospholipids of cell membranes.
PHOSPHOROUS
-minerals that are minimally required by microbes, and
are also essential in enzymatic reaction.
TRACE ELEMENTS
- required by aerobic microorganisms, it is toxic
to anaerobic bacteria like Clostridium tetanus.
OXYGEN
-are essential organic compounds that cannot
be synthesized by an organism thus must be obtained from the environment
ORGANIC GROWTH FACTOR
