BILD 1		                    			Dr. Nigel Crawford
Winter 1997						Due:  Feb. 6, 1997
PROBLEM SET #3

1.  What are the light and dark reactions of photosynthesis and how are 
they related?

2.  The Krebs cycle plays an important role in cells.  Where in the cell does 
it occur?  What are the key molecules that store/provide chemical energy 
for this cycle?  What organic compound does this cycle produce?

3.  A membrane vesicle is placed into a solution of KCl.  The vesicle is filled 
with a solution of the amino acid aspartate at neutral pH.  The membrane 
of the vesicle is permeable to K+ and Cl- but not aspartate.  What would be 
the net movement of solutes K+, Cl- and aspartate across the membrane 
and how would they distribute themselves?

4.  In plant cells, primary active transport involves the pumping of protons 
out of the cell by the H+-ATPase.  Animal cells however use the Na+-K+ 
ATPase as the primary electrogenic pump.  How does the Na+-K+ ATPase 
work to generate a gradient that stores energy across the 
plasmamembrane?  How might the transport of amino acids be coupled to 
this primary gradient in animals?

5.  Certain toxins called herbicides prevent the synthesis of ATP in 
chloroplasts.  They do not interfere with the passage of electrons down the 
electron transport chain to NADP, but they can shuttle protons across a 
membrane.  How might these toxins prevent ATP synthesis?

6.  Describe the key differences and similarities between facilitated 
diffusion and active transport and between primary and secondary active 
transport?

7.  Draw a picture of a chloroplast showing where each of the following are 
located.  Also, describe the role/function in photosynthesis of each of the 
following: (1) chlorophyll, (2) stroma, (3) thylakoid membranes, (4) grana, 
(5) RUBISCO, (6) NADPH.

8.  Identify three key components of mitochondria that are essential for 
the production of ATP and state why they are important.