Chapters 5-7 Lecture points

*Can grow in the presence of +/- oxygen

(However, grows better in the presence of oxygen)

*Requires oxygen for growth and metabolism.

(Possesses the enzymes needed to process toxic oxygen products)

Microorganims that grow at intermediate temperatures

(Grows between 10-45 C)

(Common types: those that live on/in warm blooded animals)

*Capsid

*Envelope

*Core

Adsorption-specific attachment

Penetration-entry of viral genome (is it getting across the membrane)

Uncoating-release of viral genome (host enzymes dissolve the capsid and envelope if present)

Synthesis-new viral products made

Assembly-new viruses are made in the cell

Release-often causes the host cell to lyse (break up)

*They can infect every domain of life

*Cannot exist independently from the host cell (not living)

*Needs to invade a host cell to replicate

Two main groups:

>nematodes (round worms)

>flat worms (platyhelminthes)

Another example is pinworms

*Single celled

*Fungi

*Communities-important interactions between different populations (mixed)

*Biofilms-Most don't  live planktonically (Free floating)

*Changing conditions

*Single species

*Perfect enviornmental conditions

*Artificial nutrient source

*Time required for cells to prepare for growth

*Newly innoculated cells require a period of adjustment to the enviornment

*Number of cells does not increase

*Rapid growth

-Will continue as long as nutrients are available and there are favorable conditions

*Cells reach the maximum rate of cell division

-Doubling of population will generate

*The population enters a survival mode

-Population numbers remain stable

-Death balances out the rate of multiplication

*Build up of waste products

*Depleted nutrients and oxygen

*Cells begin to die at an exponential rate

-Numbers of viable (capable of growing) cells (down)

*Total cell numbers (down)

*Prolonged decline

-Occurs once most of the cells die

-Gradual decrease in viable cells

The majority of bacteria live or grow in habitats between pH 6-8

*Neutrophiles-multiply between 5-8

*Acidophiles-thrive at pH below 5.5

*Alkalophiles-grow at pH above 8.5

*It determines the places that bacterial pathogens colonize and cause problems.

-Skin: aerobic and anaerobic pathogens

-Mouth: biofilm enviornments favor anaerobic microorganisms