Diffusion & Osmosis

Question 1

Definition of diffusion?

Answer 1

the movement of molecules from an area of high concentration to an area of low concentration

Question 2

Difference between permeable and impermeable?

Answer 2

permeable: if the substance can pass through it
impermeable: cannot pass through it

Question 3

What does selectively permeable mean?

Answer 3

allows some but not all molecules pass through

Question 4

Does diffusion require energy? It is known as?

Answer 4

does not require energy, it is known as passive transport

Question 5

Give 2 examples of diffusion.

Answer 5

in the lungs, O2 diffuses into the blood through the alveoli

food coloring in water

Question 6

What 4 factors affect the rate at which diffusion takes place?

Answer 6

temperature
distance
particle size
concentration

Question 7

Discuss temperature in affecting the rate at which diffusion takes place?

Answer 7

diffusion happens at a faster rate at higher temperatures, particles have more energy

Question 8

Discuss distance in affecting the rate at which diffusion takes place?

Answer 8

the shorter the distance, the faster the rate of diffusion

Question 9

Discuss particle size in affecting the rate at which diffusion takes place?

Answer 9

the smaller the particle size, the faster the rate of diffusion

Question 10

Discuss concentration in affecting the rate at which diffusion takes place?

Answer 10

diffusion will take place at a faster rate when there is a greater concentration difference between solutions

Question 11

Osmosis definition?

Answer 11

is the movement of water molecules across a selectively permeable membrane from a region of high concentration to a region of low water concentration

Question 12

Does osmosis require energy? It is X?

Answer 12

does not require energy, it is passive

Question 13

Osmosis is a special type of diffusion, why?

Answer 13

requires a membrane (must be across a selectively permeable membrane)
water only that moves (involves the movement of water molecules)

Question 14

Low water concentration = ?
High water concentration = ?

Answer 14

high solute
low solute

Question 15

What is a solvent? Eg?

Answer 15

a liquid that dissolves other substances, eg: water

Question 16

What is a solute? Eg?

Answer 16

a substance that has been dissolved , eg: salt/sugar

Question 17

What is a solution? Eg?

Answer 17

the mixture of solvent and solute, eg: water and sugar

Question 18

A solution of equal concentration is called?

Answer 18

isotonic

Question 19

What does isotonic mean?

Answer 19

a solution of equal concentration

Question 20

If an animal cell in a solution that is the same concentration as it’s cytoplasm, water will?

Answer 20

move in and out through its cell membrane at the same rate

Question 21

A less concentrated solution (low solute) is called?

Answer 21

hypotonic

Question 22

What does hypotonic mean?

Answer 22

a less concentrated solution

Question 23

If an animal cell is in a solution that is less concentrated than the cell, the water will? What happens to the cell?

Answer 23

move into the cell as a result of osmosis

the cell will enlarge and may burst and swell

Question 24

Eg of animal cells in less concentrated solution?

Answer 24

fresh water is less concentrated than the cell contents of amoeba

Question 25

A more concentrated solution (high solute) is called?

Answer 25

hypertonic

Question 26

What does hypertonic mean?

Answer 26

a more concentrated solution

Question 27

Animals cells is in a solution that is more concentrated than the cell, water will? What happens the cell?

Answer 27

move out of the cell as a result of osmosis the cell will shrivel

Question 28

Plant cell walls are: selectively/semi permeable, permeable or fully permeable?

Answer 28

fully permeable

Question 29

Plant cell walls let what through?

Answer 29

water, gases, many solutes (sugar, salt)

Question 30

Cell wall gives a certain amount of X to a plant cell?

Answer 30

strength

Question 31

Turgor, or turgor pressure means?

Answer 31

the outward pressure of the cell contents (cytoplasm and vacuole) pushing against the cell wall

Question 32

How can plasmolysed cells be restored to normal by doing what? Give eg.

Answer 32

placing them in a less concentrated solution eg: water

Question 33

(Plant cells in more concentrated solution), the more concentrated solution does what? What happens the cell?

Answer 33

the more concentrated solution fills the space between the cell membrane and the cell wall the cell loses turgor pressure

Question 34

Regarding osmosis and food preservation, osmosis is sometimes used for?

Answer 34

to kill microorganisms and stop them decaying food

Question 35

Bacteria and fungi are similar to plants as?

Answer 35

they also have a cell wall, their cells have a high water content

Question 36

Give examples of food preservation techniques based on osmosis.

Answer 36

- foods like fish can be soaked in a high concentration salt solution, any microorganisms in or on the fish will lose water and die as a result of osmosis. - fruits can be preserved in the form of jams and marmalades by using a high sugar concentration, this dehydrates (plasmolyse the cell) microorganisms and prevents them from growing

Question 37

Osmoregulation meaning?

Answer 37

the maintenance of water and salt balance in an organism