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Cell Membrane Proteins general not needed where simple diffusion possible (e.g. O2) types of passive cross membrane activity simple diffusion diffusion through membrane osmosis water passing through a thin protein channel facilitated difusion large protein channel allows diffusion types of active cross membrane activity active transport uses ATP via ATP Hydrolosis energy sources ATP created through oxidative phosphorylation oxidation-reduction reactions in mitochondria process food glycolysis, etc krebs cycle product of above 2 substrates oxidative phosphorylation ADP -> ATP membrane pumps use energy to move substances against the concentration gradient move things in a low concentration to a high concentration enzymatic activity that consumes energy (ATP) primary active transport can cause secondary active transport example - leaking back in of same ion pumped out most ATP in body is used as supply for pumps most pumps move cations (positive ions, like NA+ K+ CA++) types ATP driven transport - ATPase pump ATP -> via ATPase release phosphor -> ADP subtypes F0F1 made of 8 subunits in mitochondria used for moving H+ V0V1 made of 8 subunits in lysosomes used for moving H+ P-Type subtypes NA+K+  ATPase exchanges NA for K muscle and nerve cells H+K+  ATPase exchanges H for K stomach and kidney membranes SERCA CA++ ATPase SERCA = smooth endoplasmic reticulum CA Pump in sarcoplasmic reticulum (muscle cells) actively remove calcium from cell ABC-Transporters as a family most diverse subtypes MDR transports chemotherapy drugs in to cell CFTR found in respiratory and pancreatic cells Cystic-fibrosis transporter transports chloride MDR2 in liver cell bile secretion membrane channels integral membrane proteins contain pores sometimes open, some times closed some cooperate with pumps participate in regulating electrical potential of cell main channels sodium potasium calcium some can be gated can be one sided or two active (all open) or inactive (all closed)  state stimulus to open can be electrical chemical called ligans channel then called receptors photo mechanical memrane carriers qualities made of singe polypeptides usually alpha helix shape spiral called a secondary structure some beta sheet flat squigal called a secondary structure if you combine 2 structures - tertiary structure if you combine 2 tertiary structures you get a quatenary structure these are "integral proteins" since they cross membrane they do not change substrates in process types uniporter facilitatated diffusion of one substrate example Glucose Transporter (GLUT) GLUT 1 most cells in particular red blood celss GLUT 2 liver cells pancreas beta cells hypothalmus small intestine GLUT 3 placenta nerve cells testies GLUT 4 heart cells skeleton muscles GLUT 5 small intestine sperm symporters facilitates a primary and secondary substrate together  SGLT1 Sodium + Glucose transporter small intestines NKC1 Sodium Potassium 2-Chlorides transporter in kidney, intestines and lungs antiporter one substrate in one direction the other in the opposite direction NHE1 NA+ / H+ acid base (PH) balance kidney and intestines Band 3 in red blood cells HCO3- / CL- acid base (PH) balance

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