IGCSE Biology Revision Notes Movement In and Out of Cells/ 2023/2024/2025/2026/2027/2028 Exams

IGCSE Biology Revision Notes Movement In and Out of Cells/ 2023/2024/2025/2026/2027/2028 Exams cover the following objectives:

3.1 Diffusion

Core

1 Describe diffusion as 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
2 State that the energy for diffusion comes from the kinetic energy of random movement of molecules and ions
3 State that some substances move into and out of cells by diffusion through the cell membrane
4 Describe the importance of diffusion of gases and solutes in living organisms
5 Investigate the factors that influence diffusion, limited to: surface area, temperature, concentration gradient and distance

3.2 Osmosis

Core

1 Describe the role of water as a solvent in organisms with reference to digestion, excretion and transport
2 State that water diffuses through partially permeable membranes by osmosis
3 State that water moves into and out of cells by osmosis through the cell membrane
4 Investigate osmosis using materials such as dialysis tubing
5 Investigate and describe the effects on plant tissues of immersing them in solutions of different concentrations
6 State that plants are supported by the pressure of water inside the cells pressing outwards on the cell wall Supplement
7 Describe osmosis as 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
8 Explain the effects on plant cells of immersing them in solutions of different concentrations by using the terms: turgid, turgor pressure, plasmolysis, flaccid
9 Explain the importance of water potential and osmosis in the uptake and loss of water by organisms

3.3 Active transport

Core

1 Describe active transport as 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

Supplement

2 Explain the importance of active transport as a process for movement of molecules or ions across membranes, including ion uptake by root hairs
3 State that protein carriers move molecules or ions across a membrane during active transport