Newbie: Python + C Question

[bourassa]

Hi there.  I have a question about Python and the interaction with C. 
 From Python I can use C extensions.  But does doing so speed up 
execution speed?  When Python uses the C extension does it just process 
it in an interpreted fashion or does the code written in C run like a 
compiled C program?  Or have I really misunderstood the whole concept, 
in which case do you have a good reference :-)  TIA

Majb