Tutor profile: Daniel B.
Subject: Organic Chemistry
How many Chiral centers are located in the following molecule: http://www.raw-milk-facts.com/images/Cholesterol2.gif
There are 8 chiral centers in Cholesterol
When the Bifidobacterium sp. strain grows on glucose in the absence of oxygen it excretes lactate and acetate into the growth medium. What predictions about Bifidobacterium metabolism could be made based on these observations:
The Strain is capable of fermentation
Describe activation and inactivation of a heterotrimeric G protein beginning with ligand binding to a G-Protein Coupled Receptor.
1. The ligand Binds to the G-Protein Coupled Receptor and Activates it. 2. The activated G-Protein Coupled Receptor binds the heterotrimeric G-Protein. This causes the G-Protein to release Guanosine diphosphate and bind Guanosine Triphosphate. 3. The binding of Guanosine Triphosphate activates the alpha subunit of the heterotrimeric G-Protein, the beta and gamma subunits are released. 4. The alpha subunit binds to an effector enzyme and alters its activity. 5. The alpha subunit hydrolyses the Guanosine triphosphate to Guanosine diphosphate. The beta and gamma subunits are able to bind this in order to deactivate the protein.
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