studying for finals...

Karen Ferri kferri at email.unc.edu
Sun Dec 4 00:35:20 EST 1994


Hello all:
	I have posted to this grp. before and have always had luck in 
getting responses to my questions so here it goes again..
	I am studying for my micro final and I need some clarifications:
1) Phototaxis: when bacteria go into darkness, they stop, and reverse 
direction back into light.  Called shock response.  My book says this is 
different from chemotaxis but doesn't give details.  They both are 
behavioral responses, are they not?  The only diff. I see is that in 
chemotaxis, there is a physical agent that actually binds to the cell to 
influence flagellar rotation.  Light obviously can't bind to anything.  
Is this the difference they are talking about?
2) Reducing bacteria: reduce compounds using external e- donors and ATP.  
This reduction results in a PMF being generated which allows for ATP 
synthesis.  This new ATP can be used in the reduction of other compounds 
(replaces ATP used in step 1).  Is this statement correct?
3) Chemolithotrophs oxidize inorganic cmpds. to get e- for reducing power 
and the synthesis of ATP.  These 2 things then reduce CO2 to 
polysaccharides.  How can this be called aerobic respiration by 
microorganisms when CO2 is converted to polysaccharides.  I thought 
respiration was the reduction of polysaccharide to CO2?

Sorry this is so long.  Thanks in advance for your help.  This is my last 
final before graduation on the 18th!!!!

B.S biology UNC- Chapel Hill

KF




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