chapter 6- microbial growth part 1 (types of microbes + environments+ indirect/direct methods)

Microbial Growth is increase in ___ not __ that result in populations & colonies

increase in \[# of cells\] not \[cell size\]

The four phases of microbial growth are:

“L,L,S,D”

1) Lag

2) Log

3) Stationary

4) Death

Difference between Lag vs Log phase:

Lag phase = intense activity *prepping* for growth, no popltn. increase

Log phase = binary fission (bacteria) or mitosis(yeast) and logarithmic population growth

5 types of microbial groups, depending on temperature \[from least to greatest heat-loving\]

(psyPhile→psyTroph ,meso →thermo , hypotherm)

\-psychorophiles

\-psychotrophs

\-mesophiles

\-thermophiles

\-hyperthermophiles

What is special about Psychotrophs- what do they cause?

psychotrophs cause \[food spoilage between 0C & 20-30 C \]

pH range of bacteria

6\.5 - 7.5 pH

pH range of molds, and yeasts

5-6 pH

environments: Acidophile vs Alkalinophile

Acido- acidic environments

alkalino-alkaline environments

**Halophiles** require a \[high/low\] concentration of ___

require a \[high\] concentration of salt

**osmotolerant** microbes \[do/do not\] require high concentration of solute, but \[can/can’t\] tolerate if high

microbes \[do not\] require high…but \[can\] tolerate if high

**Barophiles** can survive under \[normal/extreme\] pressure and will explode if exposed to \[normal/extreme\] atmospheric pressure

can survive under \[extreme\] pressure & will explode if exposed to \[normal\] atmospheric pressure

**Plasmolysis** is caused by the increase of \[ __ or__\]

increase of \[salt or sugar\]

**obligate halophiles-** \[require/tolerate\] high osmotic pressure

while

**facultative halophiles-** \[require/tolerate\] high osmotic pressure

obligate halophiles- \[require\] high osmotic

facultative halophiles- \[tolerate\] high osmotic

**Indirect methods of Microbial growth: (3)**

TurMaDwei (instead of TMI)

\-Turbidity

\-Metabolic Activity

\-Dry Weight

**Direct methods** of Microbial growth: (4)

FiMPlacDmc

\-Filtration

\-MPN

\-Plate Counts

\-Direct microscopic count