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Flashcards in 4.3: Osmosis Deck (41):
1

Osmosis

Osmosis is the passage of water from a region where it has a higher water potential to a region where it has a lower water potential through a selectively permeable membrane

2

A solute

A solute is any substance that is dissolved in a solvent

3

Water potential is measured in units of what?

Water potential is measured in units of pressure

4

Water potential is measured in units of pressure, usually what?

Water potential is measured in units of pressure, usually kiloPascals (kPa)

5

Water potential is measured in units of pressure, usually kiloPascals (kPa).
Water potential is the pressure created by water molecules.
Under standard conditions of temperature and pressure (25 degrees Celsius and 100 kPa), pure water is said to have a water potential of what?

Under standard conditions of:
1. Temperature
2. Pressure
(25 degrees Celsius and 100 kPa), pure water is said to have a water potential of 0

6

Water potential is measured in units of pressure, usually kiloPascals (kPa).
Water potential is the pressure created by water molecules.
Under standard conditions of temperature and pressure (25 degrees Celsius and 100 kPa), pure water is said to have a water potential of 0.
The addition of a solute to pure water will do what?

The addition of a solute to pure water will lower its water potential

7

Water potential is measured in units of pressure, usually kiloPascals (kPa).
Water potential is the pressure created by water molecules.
Under standard conditions of temperature and pressure (25 degrees Celsius and 100 kPa), pure water is said to have a water potential of 0.
The addition of a solute to pure water will lower its water potential.
The water potential of a solution must always be what?

The water potential of a solution must always be less than 0, a negative value

8

Water potential is measured in units of pressure, usually kiloPascals (kPa).
Water potential is the pressure created by water molecules.
Under standard conditions of temperature and pressure (25 degrees Celsius and 100 kPa), pure water is said to have a water potential of 0.
The addition of a solute to pure water will lower its water potential.
The water potential of a solution must always be less than 0, a negative value.
The more solute that is added (the more concentrated a solution), the what its water potential?

The more solute that is added (the more concentrated a solution), the lower (more negative) its water potential

9

Water potential is measured in units of pressure, usually kiloPascals (kPa).
Water potential is the pressure created by water molecules.
Under standard conditions of temperature and pressure (25 degrees Celsius and 100 kPa), pure water is said to have a water potential of 0.
The addition of a solute to pure water will lower its water potential.
The water potential of a solution must always be less than 0, a negative value.
The more solute that is added (the more concentrated a solution), the lower (more negative) its water potential.
Water will move by osmosis from a region of higher (less what) water potential to one of lower (more what) water potential?

Water will move by osmosis from a region of:
1. Higher (less negative) water potential
to
2. One of lower (more negative) water potential

10

One way of finding the water potential of cells or tissues is to place them in a series of solutions of different water potentials.
Where this is no net gain or loss of water from the cells or tissues, the water potential inside the cells or tissues must be what?

Where this is no net gain or loss of water from the cells or tissues, the water potential inside the:
1. Cells
Or,
2. Tissues
must be the same as that of the external solution

11

While diffusion can be the movement of any molecule, osmosis is the movement of what only?

While diffusion can be the movement of any molecule, osmosis is the movement of water molecules only

12

All water potential values are what?

All water potential values are negative

13

All water potential values are negative.
What is the highest water potential?

The highest water potential is 0

14

All water potential values are negative.
The highest water potential is 0.
Therefore, the lower the water potential, the more what it becomes?

Therefore, the lower the water potential, the more negative it becomes

15

Animals cells, such as red blood cells, contain a variety of what dissolved in their watery cytoplasm?

Animals cells, such as red blood cells, contain a variety of solutes dissolved in their watery cytoplasm

16

Animals cells, such as red blood cells, contain a variety of solutes dissolved in their watery cytoplasm.
If a red blood cell is placed in pure water, it will do what?

If a red blood cell is placed in pure water, it will absorb water by osmosis

17

Animals cells, such as red blood cells, contain a variety of solutes dissolved in their watery cytoplasm.
If a red blood cell is placed in pure water, it will absorb water by osmosis, because it has what?

If a red blood cell is placed in pure water, it will absorb water by osmosis, because it has a lower water potential

18

Animals cells, such as red blood cells, contain a variety of solutes dissolved in their watery cytoplasm.
If a red blood cell is placed in pure water, it will absorb water by osmosis, because it has a lower water potential.
Cell surface membranes are very what (how much)?

Cell surface membranes are very thin (7 nm)

19

Animals cells, such as red blood cells, contain a variety of solutes dissolved in their watery cytoplasm.
If a red blood cell is placed in pure water, it will absorb water by osmosis, because it has a lower water potential.
Cell surface membranes are very thin (7 nm) and, although they are flexible, they cannot do what?

Cell surface membranes are very thin (7 nm) and, although they are flexible, they cannot stretch to any great extent

20

Animals cells, such as red blood cells, contain a variety of solutes dissolved in their watery cytoplasm.
If a red blood cell is placed in pure water, it will absorb water by osmosis, because it has a lower water potential.
Cell surface membranes are very thin (7 nm) and, although they are flexible, they cannot stretch to any great extent.
The cell-surface membrane will therefore do what?

The cell-surface membrane will therefore break

21

Animals cells, such as red blood cells, contain a variety of solutes dissolved in their watery cytoplasm.
If a red blood cell is placed in pure water, it will absorb water by osmosis, because it has a lower water potential.
Cell surface membranes are very thin (7 nm) and, although they are flexible, they cannot stretch to any great extent.
The cell-surface membrane will therefore break, doing what?

The cell-surface membrane will therefore break:
1. Bursting the cell
2. Releasing its contents

22

Animals cells, such as red blood cells, contain a variety of solutes dissolved in their watery cytoplasm.
If a red blood cell is placed in pure water, it will absorb water by osmosis, because it has a lower water potential.
Cell surface membranes are very thin (7 nm) and, although they are flexible, they cannot stretch to any great extent.
The cell-surface membrane will therefore break, bursting the cell and releasing its contents.
In red blood cells, this is called what?

In red blood cells, this is called haemolysis

23

Animals cells, such as red blood cells, contain a variety of solutes dissolved in their watery cytoplasm.
If a red blood cell is placed in pure water, it will absorb water by osmosis, because it has a lower water potential.
Cell surface membranes are very thin (7 nm) and, although they are flexible, they cannot stretch to any great extent.
The cell-surface membrane will therefore break, bursting the cell and releasing its contents.
In red blood cells, this is called haemolysis.
To prevent this happening, animal cells normally do what?

To prevent this happening, animal cells normally live in a liquid that has the same water potential as the cells

24

Animals cells, such as red blood cells, contain a variety of solutes dissolved in their watery cytoplasm.
If a red blood cell is placed in pure water, it will absorb water by osmosis, because it has a lower water potential.
Cell surface membranes are very thin (7 nm) and, although they are flexible, they cannot stretch to any great extent.
The cell-surface membrane will therefore break, bursting the cell and releasing its contents.
In red blood cells, this is called haemolysis.
To prevent this happening, animal cells normally live in a liquid that has the same water potential as the cells.
With red blood cells, what is the liquid?

With red blood cells, the liquid is the blood plasma

25

Animals cells, such as red blood cells, contain a variety of solutes dissolved in their watery cytoplasm.
If a red blood cell is placed in pure water, it will absorb water by osmosis, because it has a lower water potential.
Cell surface membranes are very thin (7 nm) and, although they are flexible, they cannot stretch to any great extent.
The cell-surface membrane will therefore break, bursting the cell and releasing its contents.
In red blood cells, this is called haemolysis.
To prevent this happening, animal cells normally live in a liquid that has the same water potential as the cells.
With red blood cells, the liquid is the blood plasma.
If a red blood cell is placed in a solution with a water potential lower than its own, what happens?

If a red blood cell is placed in a solution with a water potential lower than its own:
1. Water leaves by osmosis
2. The cell shrinks and becomes shrivelled

26

Water molecules do what across the membrane at the same time?

Water molecules move in both directions across the membrane at the same time

27

Plant cell walls are fully permeable to what?

Plant cell walls are fully permeable to all molecules

28

Cytoplasm is fluid (cytosol) and contains organelles.
It is surrounded by the plasma membrane.
The vacuole contains watery cell sap (a solution of salts and other dissolved substances).
The vacuole is separated from the cytoplasm by what?

The vacuole is separated from the cytoplasm by a semi-permeable membrane (a tonoplast)

29

Hypertonic

Hypertonic is when there is more solute concentration

30

Hypotonic

Hypotonic is when there is less solute concentration

31

Isotonic

Isotonic is when there is the same solute concentration

32

Hypertonic is when there is more solute concentration.
There is less what, because there is more solute present?

There is less free water, because there is more solute present

33

Hypertonic is when there is more solute concentration.
There is less free water, because there is more solute present, so there is a what water potential?

There is less free water, because there is more solute present, so there is a lower water potential

34

Hypotonic is when there is less solute concentration.
There is lower solute present, which means more what?

There is lower solute present, which means more free water

35

Hypotonic is when there is less solute concentration.
There is lower solute present, which means more free water, so there is a what water potential?

There is lower solute present, which means more free water, so there is a higher water potential

36

Isotonic is when there is the same solute concentration.
There is the same amount of free water and there is the same what?

1. There is the same amount of free water
2. There is the same water potential

37

Isotonic is when there is the same solute concentration.
There is the same amount of free water and there is the same water potential, so there is no what?

1. There is the same amount of free water
2. There is the same water potential
,so there is no net movement of water

38

Turgor pressure in young and soft parts of a plant provides what?

Turgor pressure in:
1. Young
2. Soft
parts of a plant provides support

39

Turgor pressure in young and soft parts of a plant provides support.
What does reduced turgor pressure result in?

Reduced turgor pressure results in the plant wilting

40

Turgor (pressure)

Turgor (pressure) is a force exerted outward on a plant cell wall by the water contained in the cell

41

Turgor (pressure) is a force exerted outward on a plant cell wall by the water contained in the cell.
The force gives the plant what and may help to keep it what?

The force:
1. Gives the plant rigidity
2. May help to keep it erect