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Biology OCR (5, plasma membranes) > Osmosis > Flashcards

Flashcards in Osmosis Deck (18)
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1
Q

What is the definition of osmosis?

A

the movement of water from a high water concentration to a low water concentration through a partially permeable membrane.

2
Q

What is a solute?

A

A substance dissolved in a solvent

3
Q

What is water potential?

A

The pressure exerted by water molecules as they collide with a membrane or container

4
Q

What is the symbol for water potential?

A

e

5
Q

What is water potential measured in?

A

pressure pascals or kilopascals

6
Q

What is the symbol for pressure pascals?

A

Pa

7
Q

What is the symbol for kilopascals?

A

KPa

8
Q

What is the water potential of pure water?

A

0

9
Q

How does adding more solutes affect the water potential?

A

It lowers the water potential value (below 0)

10
Q

What is the definition of hydrostatic pressure?

A

The pressure exerted by a fluid at equilibrium at a given point within the fluid

11
Q

What is hydrostatic pressure measured in?

A

kilopascals (KPa)

12
Q

What is the definition of cytolysis?

A

Cytolysis occurs when a cell bursts due to an osmotic imbalance that has caused excess water to diffuse into the cell.

13
Q

What condition would need to be present for a cell to undergo cytolysis?

A

The external environment of the cell must have a higher water potential than the cytoplasm of the cell. This will make the water diffuse into the cell via osmosis.

14
Q

What happens when a cell undergoes crenation?

A

crenation is the shrinkage of cells that occurs when the surrounding solution is hypertonic to the cellular cytoplasm. Water leaves the cells by osmosis, which causes the plasma membrane to wrinkle and the cellular contents to condense.

15
Q

What is the definition of turgid?

A

Latin word turgidus, meaning “swollen, inflated

16
Q

How does a plant cell become turgid?

A

When water enters the plant cell via osmosis the increased hydrostatic pressure pushes the membrane against the rigid wall. This prevents the entry of further water.

17
Q

What is the definition of plasmolysed?

A

The shrinking of the cytoplasm away from the cell wall of a plant due to water loss from osmosis.

18
Q

When does plasmolysed occur in a plant cell?

A

When the plant cell is placed in a solution with a lower water potential than inside of the plant cell.