Osmosis

Question 1

What is osmosis?

Answer 1

Osmosis is the net movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution), through a partially permeable membrane.

Question 2

High water potential

Answer 2

A solution with many water molecules has a high water potential.

Question 3

Low water potential

Answer 3

A solution with few water molecules has a low water potential.

Question 4

What is a solution?

Answer 4

The biochemical processes in living cells always take place in a solution. A solution is a homogeneous mixture of one or more solutes dissolved in a solvent.

Question 5

What is a solvent?

Answer 5

The substance in which the solute dissolves.

Question 6

What is a solute?

Answer 6

The substance which dissolves in the solvent.

Question 7

What is osmosis in terms of diffusion?

Answer 7

Osmosis is just a special case of diffusion and is specifically the diffusion of water molecules.

Question 8

What is water concentration?

Answer 8

The amount of water, as compared to other molecules

Question 9

What is concentration?

Answer 9

The proportion of solvent: solute

Question 10

What is an isotonic solution?

Answer 10

An isotonic solution is equal. Iso=equal. Tonic= strength

Question 11

What is a hypertonic solution?

Answer 11

Hyper=Above, Tonic=strength
Higher concentration of solvent inside the cell so it travels out of the cell.

Question 12

What is a hypotonic solution?

Answer 12

Hypo= Below
Higher concentration of solute inside the cell so solvent flow into the cell.

Question 13

Cells and osmosis

Answer 13

If a cell is placed in a solution of lower water potential, water leaves the cell by osmosis. If the cell is placed in a solution of higher water potential, water enters by osmosis.

Question 14

What happens if water enters a plant cell?

Answer 14

If water enters a plant cell by osmosis the cytoplasm will swell, but only until it pushes against the cellulose wall.

Question 15

Can the entry of water damage a plant cell?

Answer 15

A plant cell will not be permanently damaged by the entry of water.

Question 16

What happens if water leaves a plant cell?

Answer 16

If water leaves a plant cell by osmosis the cytoplasm will shrink, but the cellulose cell wall will continue to give some support.

Question 17

Can the loss of water damage a plant cell?

Answer 17

Plant cells rarely suffer damage by the loss of water.

Question 18

What happens when the cell is in a solution of lower water potential than cell contents?

Answer 18

Water leaves by osmosis. The cytoplasm pulls away from the cell wall and the cell becomes flaccid.

Question 19

Flaccid

Answer 19

Floppy

Question 20

Cell in solution of equal water potential

Answer 20

No net movement of water, cytoplasm presses against cell wall

Question 21

What happens when a cell is in a solution with higher water potential?

Answer 21

Water enters by osmosis. The cytoplasm pushes hard against the cell wall and the cell becomes turgid.

Question 22

Turgid

Answer 22

Firm

Question 23

Can osmosis damage animal cells?

Answer 23

Osmosis is potentially damaging to animal cells, and animals have mechanisms to keep blood plasma and the body fluids at the same water potential as the cytoplasm of cells. In mammals the kidney plays a vital part in this process of osmoregulation.

Question 24

Red blood cell in a solution of lower water potential.

Answer 24

The cell loses water, shrinks and becomes crenated.

Question 25

Crenation

Answer 25

The formation of uneven notched corners on cells caused by osmosis water loss

Question 26

Red blood cell in a solution of the same water potential

Answer 26

The cell is in equilibrium.

Question 27

Equilibrium

Answer 27

Equilibrium is the state in which all forces acting on the body are balanced with an equal and opposite force

Question 28

Red blood cell in a solution of high water potential

Answer 28

The cell takes in water, swells and bursts. (Hemolysis)

Question 29

Ghost of red blood cell

Answer 29

Membrane left behind

Question 30

Plasmolysis

Answer 30

Plasmolysis is the process in which cells lose water when they are placed in a hypertonic solution.

Question 31

Key points: Osmosis defintion

Answer 31

Osmosis is the diffusion of water from a region of higher concentration to a region of lower concentration of water through a partially permeable membrane.

Question 32

Key points: types of solutions

Answer 32

In comparing two solutions of unequal solute concentration, the solution with the higher solute concentration is hypertonic, and the solution with the lower concentration is hypotonic. Solutions of eequal solute concentration are isotonic.