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UNIT 1:  METABOLIC PROCESSES

 

F.  Photosynthesis and Cellular Respiration

 

·           photosynthesis and respiration both take place in the same cell for autotrophs, whereas heterotrophs only undergo respiration

·           Calvin cycle processes and C4 and CAM processes are similar to reactions in cellular respiration, only they are in reverse

·           electron transport chains are found in both systems, and the proteins, quinines and cytochromes are similar in structure and, in some cases, are exactly the same

·           both photosynthesis and respiration use chemiosmosis to transform energy from one form to another

·           in mitochondria, H+ ions are pumped from the matrix into the intermebrane space, with ATP synthesis occurring in the matrix

·           in chloroplasts, H+ ions are pumped from the stroma into the thylakoid lumen, with ATP synthesis occurring in the stroma

·           Figure 2, p. 180 illustrates chemiosmosis in both processes

·           the following Table summarizes the comparisons between photosynthesis and respiration:

 

Comparison

Respiration

Photosynthesis

1.  Overall Reaction

a.  reactants

 

b.  products

 

c.  energy

 

  • organic molecules (e.g. glucose)

 

  • CO2  +  H2O

 

  • Released

 

  • CO2  +  H2O

 

  • organic molecules

 

  • stored

2.  Electrons

a.   source

 

b.  carrier(s)

 

  • organic molecules (e.g. glucose)

 

  • NAD+, FAD+

 

·         Water

 

·         NADP+

3.  Electron Transport System

a.   energy profile

 

 

 

 

 

 

 

 

b.   electron source

 

c.   electron sink

 

d.   products

 

 

 

Energy

 

 

 

 

        time

 

  • NADH and FADH2

 

  • oxygen

 

  • ATP

 

 

 

 Energy

 

 

 

 

          time

 

  • water

 

  • NADPH

 

  • ATP and NADPH

4.   ATP Synthesis and Organelle Structure and Function

a.   location of ETC

 

b.   H+ ion reservoir and the pumping action of the ions by the ETC

 

c.   membrane embedded ATPase and the  synthesis pf ATP by chemiosmosis

 

 

 

  • inter membrane (cristae)

 

  • pumped out of the matrix and into the inner membrane space

 

 

  • ATPase is oriented such that the H+ ions move from the outside in and ATP is made on the matrix side

 

 

 

 

  • thylakoid membrane

 

  • pumped into the out of the stroma and into the thylakoid lumen

 

 

  • ATPase is oriented such that the H+ ions move from the inside out and ATP is made on the stroma side

 

 

Homework:            1-5, p. 182