Microbiology (Biol 251): Lab 7

Front 1

Identify the 4 growth factors mentioned in class.

Back 1

Temperature
pH
Osmotic pressure
UV radiation

Front 2

Identify how temperature and pH affect growth.

Back 2

They affect how proteins fold into their overall 3D conformation.

Front 3

Identify the 3 types of osmotic pressure solutions.

Back 3

Isotonic solutions
Hypertonic solutions
Hypotonic solutions

Front 4

isotonic solution

Back 4

equal amount of solutes and water; net movement is zero

Note: Water is still moving, but in equal amounts both ways.

Front 5

hypertonic solution

Back 5

solution contains large amounts of solutes and less water

results = less water in the cells (AKA plasmolysis)

Front 6

hypotonic solution

Back 6

solution contains fewer amounts of solutes and more water

results = cells gaining water

Front 7

How does UV radiation affect growth?

Back 7

UV radiation leads to the formation of "thymine dimers" in DNA, which introduce mutations into subsequent rounds of replication.

Front 8

disinfectants

Back 8

antibacterial agents used on inanimate objects; very strong & harsh

i.e. Bacdown

Front 9

antiseptics

Back 9

antibacterial agents used on living tissue; should be mild

i.e. Betadine

Front 10

antibiotics

Back 10

chemicals utilized to kill or inhibit the growth of microorganisms

Front 11

bacteriostatic

Back 11

slows down or halts the growth of bacteria

Front 12

bacteriocidal

Back 12

actually "kills" bacteria

Tip: homicidal is murder

Front 13

The effectiveness of antibiotics is determined by the ________________.

Back 13

zone of inhibition.

Front 14

zone of inhibition

Back 14

clear, white area surrounding disk with no bacterial growth; used to determine the effectiveness of antiseptics and antibiotics

Front 15

Identify the 8 cleaning agents tested in lab.

Back 15

Lysol, antibacterial
Lysol, plain
Bacdown
Mouthwash
Multipurpose cleaner (Mr. Clean)
Hydrogen Peroxide
91% Alcohol
Betadine

Front 16

Identify the 2 bacteria used with the cleaning agents.

Back 16

Pseudomonas aeruginosa
S. aureus

Front 17

How do we measure the zone of inhibition for antiseptics?

Back 17

You measure the radius, from the edge of the disc to the end of the clear zone in mm.

Front 18

How do we measure the zone of inhibition for antibiotics?

Back 18

You measure the diameter, from one edge of the clear zone to the other in mm.

Front 19

Why are mannitol plates BOTH selective and differential?

Back 19

SELECTIVE
They are 7.5% NaCl, which means they are selective for bacteria that like salty environments.

DIFFERENTIAL
Contains phenol red (pH indicator) that turns yellow when acids are detected. (S. aureus, if present, will eat mannitol, and acids are produced as a byproduct.)