Lecture 25: C4 and CAM metabolism Flashcards
what is an outcome of global warming
rubisco favors oxygenation over carboxylation and increases photorespiration
how do C4 and CAM plants concentrate carbon
phosphoenolpyruvate carboxylase for the primary carboxylation reaction
C4 photosynthesis has evolved mainly in ________________ regions
hot, dry
C3 anatomy
photosynthesis=mesophyll cells
absence of kranz anatomy
no chloroplast in bundle sheath cells
relatively less thicker bundle sheath cell layers
C4 kranz anatomy
photosynthesis=mesophyll and bundle sheath cells
presence of kranz anatomy
chloroplast in bundle sheath cells
thicker bundle sheath cell layers
kranz anatomy in C4 plants
bundle sheath cells form a ring around vascular tissue and mesophyll cells form a ring around bundle sheath cells
mesophyll cells
chloroplast with grana
bundle sheath cells
starch-rich chloroplast without grana
what do transporters and plasmodesmata do
transport function of metabolites between bundle sheath and mesophyll cells
economically important C4 species in agriculture
corn, sugar cane, sorghum
advantages of C4 photosynthesis in hot and dry weather conditions
- stomata closed (prevent water evaporation and CO2 uptake
- concentration of CO2 is low
- HCO3- is generated from CO2 from Carbonic anhydrase
- phosphoenolpyruvate carboxylase fixes HCO3-
when do C4 plants have an advantage over C3 plants
when water is limiting
t/f: C4 requires less ATP energy for the additional carboxylation steps
f, need more energy
How is C4 separated for carbon assimilation and fixation
Physically separated pathways
t/f: CAM is much more widespread than C4
t
