Cell membranes
a mind map of chapter 2 cell membranes
- Created by: samsam001
- Created on: 17-03-14 19:24
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- cell membranes
- Overview
- Every living cell is surrounded by a cell membrane
- Functions
- Membranes are partially permeable, they control what enters and leaves the cell
- Membranes produce different compartments inside cells
- Membranes are important in cell signalling
- They allow electrical signals to pass through them
- Membranes provide attachment sites for enzymes and any other molecule involved in metabolism
- mechanisms of cell signalling
- receptor acts as an ion chanel
- the signal is a chemical that attaches to a protein or a glycoprotein acting as an ion channel. When the chemical attaches to the receptor it opens, letting the ions in.
- receptor activates a G-protein
- Here the receptor in the plasma membrane interacts with another molecule, a g-protein.
- When the signal molecule attaches to the receptor, the G-protein is activated
- the g-protein the activate an enzyme which brings about the reaction
- When the signal molecule attaches to the receptor, the G-protein is activated
- Here the receptor in the plasma membrane interacts with another molecule, a g-protein.
- receptor acts as an ion chanel
- mechanisms of cell signalling
- Structure
- all have similar structure. they are normally between 7-10 nm. Meaning they are invisible under a light microscope, but visible with an electron microscope
- They are formed of a double layer of molecule called phospholipids,which have many proteins in them
- Phospholipid bilayer
- Phospholipids have hydrophilic head and hydrophobic tail
- the cytoplasm has a lot of water and so does the outside. the hydrophilic heads are therefore attracted to the fluids and the tail isn't so this forms a double layer with the heads facing the fluids and the tails facing each other
- membranes also contain cholesterol, glycoproteins and glycolipids
- Fluid mosaic model
- fluid refers to the fact that the molecules in the membrane are in constant motion
- mosaic refers to how it would look from above
- cell signalling
- cells must stay in contact in order to survive
- in multi-cellular organisms, cells in one part need to communicate with cells in another
- Signals arrive at the plasma membrane from the outside, i.e a hormone
- a receptor in the cells plasma membrane receives the signals and brings about actions, this is called cell signalling
- mechanisms of cell signalling
- receptor acts as an ion chanel
- the signal is a chemical that attaches to a protein or a glycoprotein acting as an ion channel. When the chemical attaches to the receptor it opens, letting the ions in.
- receptor activates a G-protein
- Here the receptor in the plasma membrane interacts with another molecule, a g-protein.
- When the signal molecule attaches to the receptor, the G-protein is activated
- the g-protein the activate an enzyme which brings about the reaction
- When the signal molecule attaches to the receptor, the G-protein is activated
- Here the receptor in the plasma membrane interacts with another molecule, a g-protein.
- receptor acts as an ion chanel
- Overview
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