1. Active Transport, Transmembrane Proteins, and Neurons AP Biology 2006

2. Carrier Proteins

3. Exocytosis and Endocytosis Movement of large molecules out of the cell http://www.bbc.co.uk/education/asgur u/biology/01cellbiology/05pathways/0 9endoexo/index.shtml http://www.bbc.co.uk/education/asgur u/biology/01cellbiology/05pathways/0 9endoexo/index.shtml

4. Receptor Mediated Endocytosis

5. LIGANDS a ligand is an atom, ion or functional group that donates its electrons through a coordinate covalent bond to one or more central atoms or ions, usually metals. An array of such ligands around a center is termed a complex.atomionfunctional groupcoordinate covalent bondmetalscomplex

6. Ligands Can open a gated channel Can participated in cell signalling Can participate in receptor mediated endocytosis

7. LIGANDS

8. Ligand Gated Channels

9. Receptor Mediated Endocytosis

11. Primary Active Transport http://www.bbc.co.uk/education/asgur u/biology/01cellbiology/05pathways/0 8active/index.shtml http://www.bbc.co.uk/education/asgur u/biology/01cellbiology/05pathways/0 8active/index.shtml

12. Active Transport http://www.stolaf.edu/people/giannini/ flashanimat/transport/secondary%20a ctive%20transport.swf http://www.stolaf.edu/people/giannini/ flashanimat/transport/secondary%20a ctive%20transport.swf

13. ABC Transporters Transporters are transmembrane proteins that expose a ligand-binding domain at one surfacetransmembrane proteins ATP-binding domain at the other surface. The ligand-binding domain is usually restricted to a single type of molecule

15. Complexity of transport

16. ABC ABC ABC ("ATP-Binding Cassette"). The ATP bound to its domain provides the energy to pump the ligand across the membrane. The human genome contains 48 genes for ABC transporters. Some examples:ATPhuman genome

17. Examples CFTR — the cystic fibrosis transmembrane conductance regulator CFTR TAP, the transporter associated with antigen processing. the transporter that liver cells use to pump the salts of bile acids out into the bile.salts of bile acids ABC transporters that pump chemotherapeutic drugs out of cancer cells thus reducing their effectiveness. ABC transporters must have evolved early in the history of life. The ATP-binding domains in archaea, eubacteria, and eukaryotes all share a homologous structure, the ATP-binding "cassette".archaea eubacteriahomologous

18. Gated and NON Gated Channels

20. The Action Potential The action potential is electrical in nature It moves along the neuron like a wave The action potential involves highly selective and controlled ion movement through specialized channels and pumps The distribution of ions outside and inside of a membrane is maintained by these transmembrane proteins Na+ is the major extracellular ion and K+ and P - ( proteins) are the major intracellular ions The outside has a positive charge in regard to the outside Cl- Na + P- K+K+

21. Ion Channels and the Action Potential The membrane is polarized. This is the resting potential of the membrane The sodium channel opens and sodium ions rush into the inside of the axon The potassium gates open up and potassium rushes out of the cell The potssium gates are slower This is the action potential. It produces a wave of - charge that moves down the neuron The sodium pumps binds three sodiums and passes them to the outside and two potassium and passes them to the inside- this is like a “ swinging door”. Finally the membrane returns to the resting potential

22. The Origin and Transmission of Neural Impulses Neural impulses are generated by an action potential The action potential is generated when the membrane of the neuron which has a positive charge on the outside is depolarized in a wave along its length +++++++++++++++++++++++++++++ +++ ------------------------------- --- ++++++++++++++++++++++++++++ ++ -60mv 30mv polarized depolarize d

23. The Wave +++----- +++++ ---+++++----- - The Wave The axon Repolarized – depolarized - polarized

24. Electrochemical Changes During the Action Potential

25. Voltage Changes during the Action Potential