2d Movement of substances into and out of cells Flashcards Preview

IGCSE Biology > 2d Movement of substances into and out of cells > Flashcards

Flashcards in 2d Movement of substances into and out of cells Deck (10):
1

Define diffusion. (3)

- Diffusion is the net movement of particles
- from an area of higher concentration to an area of lower concentration
- down the concentration gradient.

2

What factors affect the rate of diffusion? (4)

- Concentration gradient
- Surface area to volume ratio
- Diffusion distance
- Temperature

3

What factors increase the rate of diffusion? (4)

- Steep concentration gradient
- High SA:Vol ratio
- Short diffusion distance
- High temp (leading to increased kinetic energy)

4

Define active transport. (4)

- Active transport is the net movement of particles
- from an area of lower concentration to an area of higher concentration
- against a concentration gradient
- using energy released during respiration.

5

Give two examples of active transport. (2)

- Root hair cells absorbing mineral ions.
- Movement of glucose through the lining of the small intestine.

6

Define osmosis (3)

- Osmosis is the net movement of water
- from an area of higher water potential to lower water potential
- through a partially permeable membrane.

7

What happens to a plant cell placed in salty solution and why? (3)

- The plant cell shrinks/becomes flaccid.
- The cell membrane pulls away from the cell wall (plasmolysis)
- because there is a higher water potential than in the salty solution compared with the cell, so the water leaves the cell by osmosis.

8

What happens to a plant cell placed in pure water and why? (3)

- The plant cell swells/becomes turgid.
- because there is a higher water potential in the surrounding solution compared with the inside of the cell, so water enters the cell by osmosis.
- The cell wall prevent the cell from bursting however.

9

What happens to an animal cell placed in pure water and why? (3)

- The animal cell bursts
- because there is a higher water potential in the surrounding solution compared with the inside of the cell, so water enters the cell by osmosis.
- There is no cell wall, so the cell bursts.

10

Give 3 examples of large surface area to volume ratios for quicker movement of substances. (3)

- Alveoli in lungs for absorption of oxygen.
- Villi in small intestine for absorption of soluble products of digestion.
- Root hair cells for absorption of mineral ions.