Biology Midterm 2 Study Guide Notes.

Biology Midterm 2 – Study Notes Chapter 5 – Cell Membranes and Signalling 5.3 Membrane Proteins 5.3 a They Key Functions of Membrane Proteins - Membrane proteins separate into four functional categories - Transport o Substances cannot freely diffuse through membrane o A protein provides a hydrophilic channel – allows movement of molecule o Membrane protein changes shape – shuttle molecules from one side of membrane to other - Enzymatic Activity o Enzymes = membrane proteins o Enzymes associated with respiratory & photosynthetic electron transport chains - Signal Transduction o Membranes contain receptor proteins on outer surface – bind to chemicals o Binding – receptors trigger changes on inside surface of membrane – lead to transduction of signal through the cell - Attachment/Recognition o Proteins exposed