Topic 1.4: membrane transport
Essential Ideas:
- Membranes control the composition of cells by active and passive transport.
Molecules on the move: crossing biological membranes
1.4U1: Particles move across membranes by simple diffusion, facilitated diffusion, osmosis and active transport.
1.4U2: The fluidity of membranes allows materials to be taken into cells by endocytosis or released by exocytosis. Vesicles move materials within cells.
Energy required: active transport moves molecules against natural gradients
1.4A1: Structure and function of the sodium-potassium pumps for active transport and potassium channels for facilitated diffusion in axons.
Osmosis applications
1.4A2: Tissues or organs to be used in medical procedures must be bathed in a solution with the same osmolarity as the cytoplasm to prevent osmosis.
1.4Skill: Estimation of tissue osmolarity in tissues by bathing samples in hypotonic and hypertonic solutions.
1.4U1: Particles move across membranes by simple diffusion, facilitated diffusion, osmosis and active transport.
1.4U2: The fluidity of membranes allows materials to be taken into cells by endocytosis or released by exocytosis. Vesicles move materials within cells.
Energy required: active transport moves molecules against natural gradients
1.4A1: Structure and function of the sodium-potassium pumps for active transport and potassium channels for facilitated diffusion in axons.
Osmosis applications
1.4A2: Tissues or organs to be used in medical procedures must be bathed in a solution with the same osmolarity as the cytoplasm to prevent osmosis.
1.4Skill: Estimation of tissue osmolarity in tissues by bathing samples in hypotonic and hypertonic solutions.