C4 and CAM Plants

-Mild climate
-Ontario plants
-C3 pathway
-Photorespiration
-RUBISCO is the enzyme

Plants in a low stress environment (C3)

-Tropical grasses (ex: sugarcane)
-More sun, higher temps
-C3 and C4 pathway
-No photorespiration
-PEP carboxylase and RUBISCO are the enzymes

Plants in a medium stress environment (C4)

-Desert plants: cacti
-Even more sun, higher temps, and less precipitation
-C3 and C4 pathway
-No photorespiration
-PEP carboxylase and RUBISCO are the enzymes

Plants in a high stress environment (CAM)

-Just as many on top as on bottom of leaf
-Ex: plants can stand straight up, more partially closed stomata - still get enough CO2

Stomates in C4 plants

never more than 3 cells away from bundle sheath cell

Describe the mesophyll in C4 plants

-Large
-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

-Mesophyll

C4 pathway starts in the ____________ cells

-Day
-Day
-Night

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

oxaloacetate

-CO2
-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?

-Night
-Day

When do CAM plants undergo C4 and C3 pathways?

-Temporal (time)

The separation of C3 and C4 pathways is ___________ in CAM plants