2.10: Effect of osmotic pressure on microbial growth

Question 1

?? is essential to all forms of life and is an essential source of electrons and hydrogen ions:

Answer 1

-water

Question 2

species of bacteria and archaea, like plants, require water to maintain cellular ??

Answer 2

-turgor pressure
-internal pressure against the cell wall

Question 3

cells with a wall require water to prevent:

Answer 3

-plasmolysis
-shrinking of the cytoplasm

Question 4

Water will move from an area of ?? solute conc. to an area of ?? solute concentration.

Answer 4

-low
-high
-osmosis

Question 5

What is the term for the force that controls osmosis:

Answer 5

-osmotic pressure

Question 6

Many bacteria turgor pressure by creating a concentration gradient that promotes ?? diffusion of water by osmosis:

Answer 6

-inward

Question 7

Halophiles:

Answer 7

-grow in salt conc. of 3% or higher

Question 8

Extreme halophiles:

Answer 8

-require salt conc. from 15%-25% AND WILL NOT SURVIVE where salinity is lower

Question 9

Osmotolerant

Answer 9

-grow over a wide range of salinities, most live where NaCl are less than 3%

Question 10

An organism that grows very well in broth containing 15-20% NaCl but very poorly or not at all in broth containing 0-10% NaCl would be called:

Answer 10

• extreme halophile

Question 11

A cell exposed to a hypertonic environment will ____ by osmosis.

Answer 11

-lose water

Question 12

What happens to a red blood cell placed in a hypotonic solution?

Answer 12

-it swells and may burst

Question 13

The movement of water through a semi-permeable membrane is called

Answer 13

-osmosis

Question 14

The net movement of water through a semi-permeable membrane is always towards the higher concentration of:

Answer 14

-solutes

Question 15

In a hypertonic solution, animal cells will:

Answer 15

-shrink and lose water

Question 16

In which direction does diffusion occur naturally?

Answer 16

-from areas of high conc. to low conc.

Question 17

Halophiles differ from anaerobic in that they:

Answer 17

-Require salt concentrations in excess up to 10%.

Question 18

An organism that grows very well in broth containing 3% NaCl but very poorly or not at all in broth containing 15% NaCl would be called:

Answer 18

-halophile

Question 19

What is diffusion?

Answer 19

-Movement of solute particles from high to low concentration

Question 20

Which of the following is true of passive transport?

Answer 20

-it requires a gradient

Question 21

An organism that grows very well in broth containing less than 3% NaCl but not at all in higher concentrations of NaCl would be called:

Answer 21

-osmotolerant