18 terms

C4 and CAM Plants

-Mild climate
-Alabama plants
-C3 plants
-C3 pathway
-RUBISCO is the enzyme
Plants in a low stress environment
-Plants in the tropics
-Tropical grasses (ex: sugarcane)
-More sun, higher temps
-C4 plants
-C3 and C4 pathway
-No photorespiration
-PEP carboxylase and RUBISCO are the enzymes
Plants in a medium stress environment
-Desert plants: cacti
-Even more sun, higher temps, and less precipitation
-CAM plants
-C3 and C4 pathway
-No photorespiration
-PEP carboxylase and RUBISCO are the enzymes
Plants in a high stress environment
-Just as many on top as on bottom of leaf
-Ex: blade of grass stands straight up, so it needs them on both sides, not just one
Stomates in C4 plants
never more than 3 cells away from bundle sheath cell
Describe the mesophyll in C4 plants
-Only place where glucose is made (during the C3 pathway) in these plants, so they have to be big
-(In C3 plants, all cells/mesophyll can make glucose)
Describe the bundle sheath cells in C4 plants
C4 pathway starts in the ____________ cells
When do C3, C4, and CAM plants open their stomates?
-CO2 combines with 3-C PEP, with the help of the PEP carboxylase enzyme, to form a 4-C oxaloacetate
1st step of C4 pathway
-First form of stable organic carbon
-How the C4 pathway gets its name
4-C oxaloacetate
-It won't accept O2 even during drought
PEP carboxylase only accepts ____
-The 4-C oxaloacetate becomes a 4-C malate
2nd step of C4 pathway
-The 4-C malate moves to bundle sheath cells from the mesophyll cells
-CO2 comes off of malate and enters the C3 pathway to make glucose
-There is a 3-C leftover, which is PEP, and the process starts over again
3rd step of C4 pathway
-The bundle sheath cells are right around the vein, so the glucose can be dumped directly into the phloem in the form of sucrose
-It doesn't have to travel from the mesophyll cells
What is efficient about the fact that in C4 and CAM plants, glucose is only made in bundle sheath cells?
-Crassulacean Acid Metabolism
What does CAM stand for?
-To take in CO2
-This conserves water, but it delays their growth rates because they can't take in sunlight at the same time
Why do CAM plants open their stomates at night?
When do CAM plants undergo C4 and C3 pathways?
-Temporal (time)
The separation of C3 and C4 pathways is ___________ in CAM plants