BRAINCAKETransport Across Cell Membranes
Revision notes for Transport Across Cell Membranes in AQA Biology (7401). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.
- Plasma MembraneAll living cells are enclosed by a plasma membrane which is made of a phospholipid bilayer.
- PhospholipidsPhospholipids are made from a glycerol molecule joined to two fatty acid chains and a phosphate group.
- ProteinsMany proteins are embedded in the phospholipid bilayer.
- CholesterolCholesterol is a hydrophobic molecule that occurs within the membrane.
- GlycolipidsGlycolipids are made from phospholipids covalently bonded to a carbohydrate chain.
- GlycoproteinsGlycoproteins are proteins attached covalently to carbohydrate chains.
- Fluid-mosaic ModelThe arrangement of the components of the plasma membrane is known as the fluid mosaic model.
- Membrane PermeabilityThe plasma membrane is selectively permeable.
- Simple DiffusionDiffusion is the net movement of molecules or ions from a region of high concentration to a region of low concentration until evenly distributed.
- Facilitated DiffusionLike simple diffusion, facilitated diffusion is a passive process.
- Protein ChannelsChannel proteins form water-filled pores across the bilayer through which specific solutes can diffuse.
- Carrier ProteinsCarrier proteins are proteins that span the plasma membrane.
- Water Potential ΨThe water potential Ψ is the pressure created by water molecules.
- OsmosisOsmosis is the passage of water from a region where it has a higher water potential to a region where it has a lower water potential through a…
- Osmosis in Animal CellsAnimal cells are enclosed in a cell membrane made of a phospholipid bilayer.
- Osmosis in Plant CellsPlant cells contain various solutes in the cytoplasm.
- Active TransportActive Transport is the movement of molecules or ions into or out of a cell from a region of lower concentration to a region of higher concentration…
- Sodium-Potassium PumpThe sodium-potassium pump is a carrier protein that actively transports sodium ions out of the cell and simultaneously transports potassium ions…
- Increasing the Rate of Movement across a MembraneThe rate of movement across a cell membrane by diffusion can be increased by increasing the surface area of the membrane, increasing the…
- Absorption in the IleumAbsorption of digested food occurs in the ileum of the small intestine.
- Co-transport in AbsorptionOn the membrane of the epithelial cell adjacent to the blood the sodium-potassium pump removes sodium from the epithelial cell lowering its…
- Oral Rehydration TherapyDiseases like typhoid or cholera infect the intestines and cause diarrhoea.
On the specification
- 3.2.3 Transport across cell membranes