steps in cellular respiration

 

3)

a. Assume a cell is respiring aerobically and is using glucose as an energy source.  What is the ultimate fate of each of the 6 carbon atoms in a glucose molecule that begins the aerobic pathway (i.e., what happens to each of the carbons and where does it happen)?

b. Indicate the location (i.e. in which compartment of which organelle) where the enzymes responsible for each step in cellular respiration would be found. 

 c. What are the overall inputs (substrates and energy sources) and outputs (products and by-products) for each step in cellular respiration? 

 d. Where in cellular respiration does feedback inhibition occur? What would happen if this feedback inhibition were removed?

e. In aerobic respiration, does inhale molecular oxygen (O2) combine chemically with carbon to produce CO2? If so, explain when this occurs. If not, describe the fate of O2 and the production of CO2.  

f. What does the electron transport chain produce? What function does this product serve in cellular respiration?

.
g. What compounds are the immediate source of the “high energy electrons” that enter the electron transport system of mitochondria? Where do these electron-donating compounds gain their electrons? What type of compounds are these electron-donating compounds?

h. Textbooks often refer to oxygen as the “final electron acceptor.”  What does this statement mean?

 i. Cyanide acts by blocking the flow of electrons in the electron transport system.  What happens to ATP production and oxygen consumption in mitochondria when cells are poisoned with cyanide?  Do the rates of oxygen consumption and ATP formation increase, decrease, or remain constant? 

 j. Does the electron transport chain produce ATP? If yes, draw the steps that directly produce ATP. If no, draw the process that directly produces ATP and explain how it relates to the electron transport chain.  

 k. What energy sources other than glucose can be used in respiration? For each energy source, a state where it enters the pathway and whether it could be used as a source of energy in anaerobic respiration (i.e., in fermentation). [Hint: Examine Fig. 9.3.]

 l. When oxygen is unavailable, some cells use anaerobic (fermentation) pathways to make ATP.  Another textbook says regarding fermentation:  “The final steps serve only to regenerate NAD+.”  What does this statement mean?  Explain using examples of specific fermentation pathways.