1.4 Communication and Signalling Flashcards
Receptor
Proteins with a binding site for a specific signal molecule. Binding causes conformational change which initiates a response in the cell.
Examples of Hydrophobic Signalling Molecules
Testosterone and Oestrogen (Steroid Hormones)
Phosphorylation Cascades
Allow more than one intracellular signalling pathway to be activated
Insulin as a Signalling Molecule
Binding of insulin to specific receptor causes an intracellular signalling cascade that triggers recruitment of GLUT4 glucose transporter proteins to the cell membrane of fat and muscle cells.
Type 1 Diabetes
Reduced insulin production
Type 2 Diabetes
Loss of receptor function (generally associated with obesity)
Importance of Exercise
Exercise triggers recruitment of GLUT4 so can improve uptake of glucose to fat and muscle cells
Resting Membrane Potential
State where there is no net flow of ions across the membrane.
Action Potential
Wave of electrical excitation along a neuron’s plasma membrane.
Components of Rhodopsin
Retinal and Opsin
How do rod cells respond to low light intensities?
High degree of amplification
Kinase
Catalyses the phosphorylation of proteins
Phosphatase
Catalyses the dephosphorylation of proteins
Why do target cells only respond to a specific receptor?
Only target cells have receptor molecules for the signalling molecule
Retinal
Light sensitive molecule
