Biology Osmosis

Question 1

What is osmosis?

Answer 1

movement of water particles from high to low water potential, through a partially permeable membrane.

Question 2

What is the solute?

Answer 2

substance that dissolves in a solvent.

Question 3

What is the solvent?

Answer 3

fluid that dissolves a solute.

Question 4

What is a solution?

Answer 4

mixture of solvent and dissolved solute.

Question 5

What is the method of the osmosis RQP?

Answer 5

1. Use a cork borer to cut 5 potato cylinders of the same diameter.
2. Use a scalpel and ruler to trim each potato cylinder so they are the same length. This means that they have the same SA:V ratio.
3. Measure the starting mass of each cylinder.
4. Measure a specified amount of sugar solution and pour into each boiling tube. Make sure each boiling tube has a different concentration of sugar.
5. Add one potato cylinder to each boiling tube and wait.
6. Remove potatoes, blot the dry and record the final mass.
7. Calculate the % change in mass of each potato cylinder.

Question 6

What is a solution called when there is a higher water concentration outside the cell than inside the cell?

Answer 6

Hypotonic- Water flows into the cell via osmosis.

Question 7

What is a solution called when there is a lower water concentration outside the cell than inside the cell?

Answer 7

Hypertonic-Water flows out of the cell via osmosis.

Question 8

What is a solution called when there is the same water concentration outside the cell than inside the cell?

Answer 8

Isotonic- Equal amounts of water flow in and out of the cell via osmosis.

Question 9

What is a plant cell called when it is filled with water?

Answer 9

Turgid

Question 10

What is a plant cell called when it loses water?

Answer 10

Plasmolysed

Question 11

What is a plant cell called when it doesn’t lose or gain water?

Answer 11

Flaccid

Question 12

What is the independent variable of the osmosis RQP?

Answer 12

Concentration of solute (sugar or salt).

Question 13

What is the dependent variable of the osmosis RQP?

Answer 13

% change in mass.

Question 14

What are some control variable of the osmosis RQP?

Answer 14

Volume of solution
Volume/mass of potato pieces
Blotting technique
Temperature
Time

Question 15

What is a risk assessment of the osmosis RQP?

Answer 15

Cork Borer- press down onto a white tile to avoid cutting yourself.
Scalpel- Keep fingers away from the blade and cut away from yourself to avoid cutting yourself.

Question 16

What will happen to the potato cells in the solution with the lowest sugar concentration?

Answer 16

There is the highest water concentration so water flows into the potato cells via osmosis.

Question 17

What will happen to the potato cells in the solution with the highest sugar concentration?

Answer 17

There is the lowest water concentration so water flows out of the potato cells via osmosis.