BRAINCAKEMembranes
Every cell is surrounded by a cell surface membrane (plasma membrane), and in eukaryotic cells membranes also surround and form many organelles. All of these membranes have the same basic structure, a phospholipid bilayer with proteins, about 7 to 10 nm thick.
Functions of the cell surface membrane
• It is partially permeable: it separates the cell contents from the outside and controls which substances enter and leave.
• It carries receptors that detect hormones and other signalling molecules, so cells can communicate.
• It carries glycoproteins and glycolipids that act as antigens, allowing cell recognition, for example by the immune system.
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Key terms in this lesson
- phospholipid bilayer
- Two layers of phospholipid molecules with hydrophilic heads facing outwards towards water and hydrophobic tails facing inwards, forming membranes.
- compartmentalisation
- The separation of a cell's interior into distinct membrane-bound regions, each able to have its own conditions and enzymes.
More in Eukaryotic Cells
- Electron Microscope
- Transmission Electron Microscope
- Scanning Electron Microscope
- Ultrastructure
- Phospholipid Bilayer
- Membrane Proteins
- Fluid Mosaic Model
- Eukaryotic Cells
All 30 lessons in Eukaryotic Cells · All Edexcel AS-level Biology topics