AP BIO is TOOOOOO HOT...

what if it is tooo hot????

Alternatives to “C-3” this is the “normal” way of photosynthesis.

Alternatives to C-3 fixation gas exchange in stomata-- only occurs across a moist surface. In hot dry conditions stomata close in order to conserve H2O:

Why would this be bad for photosynthesis??

Alternatives to C-3 fixation CO2 intake decreases O2 content increases.

Photosynthetic Yield reduced

C-4 Photorespiration: Stomates close during the day to save water In HOT / DRY climates Stomates close during the day to save water ……………………low CO2

ex.

THAT IS DIFFERENT!! Isn’t it C-4 Photorespiration: These plants have 2 different types of photosynthetic cells: THAT IS DIFFERENT!! Isn’t it

Higher affinity for CO2 than RUBISCO

C-4 Photorespiration: C-C-C-C in mesophyll: PEP (enzyme) has a higher affinity for CO2 than Rubisco. 1)PEP “fixes” C, & forms a 4-C compound as the 1st product “OX”. C-C-C-C

C-C-C-C

Higher affinity for CO2 than RUBISCO

C-4 Photorespiration: 2)NADPH converts the 4-C to 2nd product (malate) and exports it to bundle sheath.

3) 4-C releases CO2 to “the Calvin” C-4 Photorespiration: 3) 4-C releases CO2 to “the Calvin” the “Calvin” occurs in bundle sheath.

C-4 Photorespiration: 4) CO2 combines with rubisco 5) the usual Calvin cycle begins. **pyruvate returns to mesophyll cells.

CAM plants

CAM Plants (Xeric conditions): 1)Open stomata at night (cooler) & close them during day--> reduces H2O loss during HOT DAY

CAM Plants (Xeric conditions): 1)Open stomata at night (cooler) & close them during day--> reduces H2O loss/ problem: cannot fix CO2 (b/c no light @ night to run the light reaction)

CAM Plants (Xeric conditions): 1)Open stomata at night (cooler) & close them during day--> reduces H2O loss/cannot fix CO2 (no light) 2)Take in CO2 at night and “fixes” the CO2 into another molecule….

C-C-C-C

CAM Plants (Xeric conditions): 3)Then incorporates it into Malate (4-C).

CAM Plants: 4)Malate stored until morning.

CAM Plants: 5)CO2 released from the Malate.

CAM Plants: 6)The CO2 then moves to the Calvin Cycle.

C3 plants are those that “do the Calvin”… Photorespiration C3 plants: Rubisco accepts O2 in place of CO2. 2)O2 is added to the Calvin Cycle instead of CO2. C3 plants are those that “do the Calvin”…

Photorespiration C-3: 3)2-C compound is made (w/ oxygen attached) and exported from the chloroplast. 4)mitochondria and peroxisomes break 2-C down into CO2 AND RELEASES IT!!! GASP.

It essentially, undoes the Calvin Photorespiration C-3: Photorespiration occurs in light and uses O2 but generates no ATP and produces no food. It essentially, undoes the Calvin

Why have it