Bundle sheath cells in C4 plants contain large chloroplasts with well-developed grana for the Calvin cycle, unlike mesophyll cells.
In the Hatch-Slack pathway, PEP carboxylase catalyzes formation of oxaloacetate (4-carbon compound) in mesophyll cells.
When light is saturating, CO2 becomes the limiting factor as RuBisCO activity depends on substrate availability.
Chloroplasts synthesize amino acids using carbon skeletons from the Calvin cycle and nitrogen from nitrite reduction.
RuBisCO catalyzes oxygenation of RuBP instead of carboxylation under high O2/CO2 ratios, initiating the photorespiratory pathway.
While soil pH affects nutrient availability, it does not directly affect the photosynthetic process itself. Chlorophyll, CO2, and light wavelength directly influence photosynthesis.
Complex I (NADH dehydrogenase) pumps 4 protons, Complex III pumps 4, Complex IV pumps 2, making Complex I the most significant proton pump.
Transpiration is highly dependent on atmospheric humidity. Lower humidity increases transpiration rate due to greater water vapor gradient.
In plants, anaerobic conditions lead to fermentation producing ethanol and CO2. Aerobic respiration yields ~30-32 ATP; Krebs cycle produces limited ATP directly; Glycolysis is cytoplasmic.
The light compensation point for C3 plants typically occurs at 50-100 μmol/m²/s where photosynthesis equals respiration rate.