Intro to Osmoregulation

Question 1

Osmoregulation

Answer 1

• Regulation of solute concentrations and water balance by a cell or organism
• Balances the uptake and loss of water and solutes

Question 2

Solute

Answer 2

A substance that is dissolved in a solution (usually water)

Question 3

Addition of sucrose

Answer 3

Reduces water potential

Question 4

Lower water potential

Answer 4

Induces water uptake from xylem

Question 5

Guard cell turgor pressure is controlled by

Answer 5

Regulation of K+ movement

Question 6

What changes the stoma size

Answer 6

Changes in turgor pressure(inflates or deflates guard cells)

Question 7

What creates solute gradients

Answer 7

Movement of salts out of the ascending limb

Question 8

In kidney: descending limb is only permeable to

Answer 8

Water

Question 9

In kidney: Ascending limb is only permeable to

Answer 9

Na+ and Cl- (may leave nephron by passive or active transport)

Question 10

Osmosis

Answer 10

The diffusion of (free) water across a selectively permeable membrane, in this case, the plasma membrane

Question 11

Water potential equation

Answer 11

Water potential = solute potential + pressure potential

Question 12

Water Potential

Answer 12

Water always moves from the system with a higher water potential to the system with a lower water potential (lower to higher solute concentration)

Question 13

Solute potential and concentration

Answer 13

Solute potential decreases with increasing solute concentration

Question 14

Osmotic forces

Answer 14

Drive the movement of water into and out of cells

Question 15

Do animal cells or plant cells burst

Answer 15

• Animal cells can burst

- Plant cells do not because of the cell wall

Question 16

Cells vs pure water osmotic potential

Answer 16

Cells have a lower osmotic potential than pure water because of the salts and proteins in them, so water moves in them

Question 17

Salt water vs cells osmotic potential

Answer 17

Salt water has a lower osmotic potential than cells, so water flows outwards

Question 18

What solution do animal cells do the best in

Answer 18

isotonic solution

Question 19

What solution do plant cells do the best in

Answer 19

Hypotonic solution

Question 20

Plant cells, water, and turgor pressure

Answer 20

Water moves into plant cell and increases turgor pressure; the cell wall pushes back and keeps the cells rigid and the plant from wilting

Question 21

Does water move up or down water potential gradient?

Answer 21

Down

Question 22

How do plants extract water from the soil

Answer 22

To extract water from the soil, a plant root must establish a water potential gradient so that water flows toward the cells of the root from the soil. The water potential must be lower in the root than in the surrounding soil