B3 Movement into and out of cells

Question 1

diffusion

Answer 1

the net movement
of particles from a region of their higher
concentration to a region of their lower
concentration (i.e. down a concentration
gradient), as a result of their random
movement

Question 2

some substances move…..

Answer 2

move into and
out of cells by diffusion through the cell
membrane

Question 3

factors that influence diffusion

Answer 3

surface area- increased causes rate to increase temperature- more KE in particles so rate of diffusion increases
concentration gradient- steeper the gradient faster the diffusion
distance- shorter distance= faster diffusion

Question 4

osmosis

Answer 4

the net movement
of water molecules from a region of higher
water potential (dilute solution) to a region of
lower water potential (concentrated solution),
through a partially permeable membrane

Question 5

PRACTICAL Investigate and describe the effects on plant
tissues of immersing them in solutions of
different concentrations

Answer 5

potato test, dialysis tubing (fake membrane)

Question 6

turgid and turgor pressure

Answer 6

contains a high amount of water, which causes the cell membrane to push against the cell wall. This pressure is known as turgor pressure, and the cell appears swollen and firm

Question 7

Flaccid

Answer 7

low turgor pressure, meaning it has lost water and its cell membrane no longer presses against the cell wall. This can result in wilting in plants

Question 8

Plasmolysis

Answer 8

When a plant cell is placed in a hypertonic solution (a solution with a higher concentration of solute than the cell), water will move out of the cell due to osmosis. This causes the cytoplasm to shrink and pull away from the cell wall, resulting in plasmolysis. A plasmolysed cell is essentially flaccid

Question 9

active transport

Answer 9

the movement
of particles through a cell membrane from
a region of lower concentration to a region
of higher concentration (i.e. against a
concentration gradient), using energy from
respiration

Question 10

Explain the importance of active transport
(include root hair cells in answer)

Answer 10

-prevents accumulation of substances that may otherwise impair cellular function
-allows cells to maintain or increase the concentration of substances
-mineral ions (nitrates) move from soil to roots against concentration gradient in plants whilst using energy from respiration