MCB 259: PLANT PHYSIOLOGY 1998, Quiz 8 – November 24,
1.Which type of CO2 fixation utilizes a separation in space between prefixation of CO2 and final fixation in the Calvin cycle?
2 Plants that use the C-4 pathway of CO2 fixation
3 What is the name of the molecule that is first carboxylated in C-4 plants? (i.e. the molecule that accepts the CO2)
4 What does the name C-4 photosynthesis refer to?
5 Which type of CO2 fixation (C-3 or C-4) will be more effective in CO2 fixation at low CO2 concentrations?A) C-3, B) C-4, C) no difference
6Which type of CO2 fixation will be more effective under conditions were photosynthesis is limited be gas exchange (low water availability)? A) C-3, B) C-4, C) no difference
7. Which of the two enzymes has the higher affinity for CO2?
8.Can You express the same idea in terms of the Michaelis Menten constant?
9.Plants growing in desserts usually have C-4, C-3, CAM metabolism (circle correct alternative)
10 Why do some C-4 plants not have grana thylacoids in their bundle sheath chloroplasts?
11 Increased CO2 concentration can lead to higher rates of CO2 fixation. You expect this effect to be
a) higher in C-4 than in C-3 plants
b) higher in plants with a high CO2 compensation point
c) higher in plants with a low CO2 compensation point.
12 What molecules/isotopes did Calvin and Bassham use to trace the fate of CO2 in photosynthesis?
13 In what molecule and where (in what cell organelle) is CO2 stored in CAM plants at night?
14 At what time of the day would you expect the least acidic pH in the vacuole of a plant with CAM?