Animation showing neurotransmission across the synaptic cleft.

synapse synaptic cleft neurotransmitter action potential presynaptic postsynaptic receptor vesicle axon terminal

Segment from the program Cells: The Structure of Life. To purchase this program please visit www.greatpacificmedia.com

cell structure cells cytoskeleton microtubules organelles microfilaments intermediate filaments tubulin microtubule organizing center centrosome spindle apparatus centrioles cila flagella basal body motor protein euglenoids vesicles biology

This course is part of a series taught by Kevin Ahern at Oregon State University on General Biochemistry. For more information about online courses go to ecampus.oregonstate.edu for the rest of the courses see www.youtube.com 1. Smell arises from nerve signals originating in nasal epithelia. Molecular components of this process include 7TM proteins that bind odorants, which activates a G protein called Golf . Golf, in turn, binds GTP, activates adenylate cyclase, stimulating cAMP synthesis. cAMP binds to a cAMP-gates ion channel in the cell membrane allowing cations to enter the cell, starting the nerve signaling process. 2. Humans have only about 30% of their odorant rcceptors active, whereas rodents a large percentage of their 1000 receptors active. Olfactory receptors (ORs) are similar in slightly structure to the beta-adrenergic receptor involved in epinephrine signaling. Each olfactory neuron synthesizes only a single OR. This differs from individual taste buds, which each synthesize several receptors for tastes. 3. We are able to perceive a VERY wide range of smells, due to the combinatorial mixing of signals from the many different 7TMs at the end of olfactory cells. 4. OR signaling proceeds via 7TM receptors that synthesize cAMP when an odorant binds to the 7TM (through the usual mechanisms). cAMP binds to a channel protein that opens when cAMP binds to it, allowing Ca++ and Na+ into the cell, thus starting the signal. 5. Smell neurons terminate in very different <b>...</b>

oregon state university osu ecampus online lecture general biochemistry chemistry science biology online lecture course class

Diffusion and Osmosis

diffusion osmosis hypertonic hypotonic solute solvent solution

5 min video on diffusion

smcblackburn science diffusion