Osmosis

Question 1

Define osmosis

Answer 1

the movement of water molecules from an area of high water potential(concentration) to an area of low water potential(concentration) across a selectively permeable membrane

Question 2

In which direction does osmosis occur from an area of H₂0 and salt and an area of H₂0

Answer 2

Question 3

In which direction does osmosis occur from an area of 40% H₂0and 60% salt and an area of 30% H₂0 and 70% salt?

Answer 3

Question 4

In which direction does osmosis occur from an area of 10% sugar and an area of 25% sugar?

Answer 4

Question 5

In which direction does osmosis occur from an area of 65% sugar and an area of 65% sugar?

Answer 5

there is no net movement

Question 6

A bag made from a semi-permeable membrane is tied to a glass tube and filled with a strong sugar solution. The bag is placed in a weak sugar solution. What will happen and why?

Answer 6

Water will move into the visking tube because there is a high water potential outside of the visking tube and a low water potential inside. Osmosis occurs from a high to low water potential.

Question 7

A bag made from a semi-permeable membrane is tied to a glass tube and filled with a weak sugar solution. The bag is placed in a strong sugar solution. What will happen and why?

Answer 7

Water will move outisde of the visking tube into the area around it. This is because there is a high water potential inside the visking tube and a low water potential outside. Osmosis occurs from high to low water potential.

Question 8

Explain the solute concentration in cells

Answer 8

cytoplasm contains water, sout, organic molecules

vacuole contains cell sap (water, amino acids, salt, glucose)

Question 9

A piece of potato is placed into a beaker with water. What will happen and why?

Answer 9

the potato cells become turgid because water goes into the potato by osmosis

water potential is lower in potato

Question 10

A piece of potato is placed into a beaker with 50% sugar. What will happen and why?

Answer 10

the potato cells become flacid because they lose water by osmosis

water potential is higher in potato

Question 11

A peice of potato is placed into a beaker with 20% of sugar. What will happen and why?

Answer 11

the potato cells become flacid because they lose water by osmosis

less flacid than 50%

Question 12

What happens to plant cells inside a solution with a very high sugar concentration?

Answer 12

water leaves cell by osmosis

cytoplasm and vacuole shrink (cell becomes plasmolysed)

flacid cells are plasmolysed

-i.e. the membrane gets pulled away from the cell wall as water is lost

Question 13

What happens to animal cells inside a solution with a very high sugar concentration?

Answer 13

water leaves cell by osmosis

cell shrinks and becomes flaccid

Question 14

What happens to plant cells inside a solution with a very low sugar?

Answer 14

water enters cell by osmosis

cytoplasm and vaculoe swell

plant cells become turgid when they take in a lot of water

Question 15

What happens to animal cells inside a solution with a very low sugar concentration?

Answer 15

water enters cell by osmosis

cell swells and might burst

Question 16

What does isotonic mean?

Answer 16

same concentration

Question 17

What does hypotonic mean?

Answer 17

lower concentration

Question 18

What does hypertonic mean?

Answer 18

higher concetration

Question 19

Summary of osmosis

Answer 19