Light Dependent
The ultimate source of electrons for NADPH.
H2O (water)
List the phases of the Calvin Cycle.
Carbon fixation, reduction, and regeneration?
These allow for gas exchange.
Stomata?
The primary pigment directly involved in converting light energy to chemical energy.
Chlorophyll a
Identify the organelles responsible for Photosynthesis and Cellular Respiration.
Chloroplasts for Photosynthesis and mitochondria for cellular respiration.
The reduction of NADP+ to NADPH decreases this in the stroma.
Proton (H+) concentration
The 5-carbon compound that initiates carbon fixation.
RuBP (ribulose-1,5-bisphosphate)
These cells are the primary site of photosynthesis.
Mesophyll cells
Purpose of accessory pigments.
Broaden the range of light absorption, sun protection, and pass energy to chlorophyll a.
This molecule is a product in photosynthesis and a reactant in cellular respiration.
Glucose (C6H12O6)
List the components of a photosystem.
1. Antenna Complex (Light harvesting complex): accessory pigments that absorb light and transfer energy.
2. Reaction Centre: specialized chlorophyll a molecules transfer energy from antenna complex to primary electron acceptor.
The name of the wasteful process when rubisco binds with O2.
Photorespiration
Predict the effect on ATP production if the thylakoid membrane became permeable to protons.
ATP production would decrease or stop, because the proton gradient across the membrane would dissipate, preventing chemiosmosis through ATP synthase.
Chlorophyll a absorbs light most efficiently at these wavelengths or colours.
Around 430 nm (blue) and 660–680 nm (red).
Compare the energy conversions in photosynthesis and cellular respiration.
Photosynthesis: light energy to chemical energy. Respiration: chemical energy to usable energy (ATP).
Photosynthesis in endergonic (requires energy) and Cellular Respiration is exergonic (releases energy).
This pathway provides additional ATP without reducing NADP+.
Cyclic photophosphorylation
Explain why it takes 6CO2 to make one glucose.
Each CO₂ contributes one carbon, and two G3P (3C each) are needed to synthesize glucose (C₆H₁₂O₆)
Describe the function of the stroma and identify which part of photosynthesis occurs there.
The stroma is the fluid-filled space around the thylakoids; it is the site of the Calvin Cycle (light-independent reactions).
Explain why green light is least effective for photosynthesis.
Green light is mostly reflected by chlorophyll pigments rather than absorbed, so it contributes little to energy capture
Explain why plants carry out both Photosynthesis and Cellular Respiration.
Photosynthesis produces glucose for energy storage, while cellular respiration breaks it down to release ATP for cellular processes.
The excited electron from P680 travels through this sequence before reaching PSI.
Pheophytin to PQ to cytochrome complex to PC
Compare the location and timing of carbon fixation and the Calvin Cycle in C3, C4, and CAM plants, and explain how these adaptations reduce photorespiration.
In C3 plants, both carbon fixation and the Calvin Cycle occur in the same cells at the same time, making them more prone to photorespiration. In C4 plants, carbon fixation occurs in mesophyll cells, and the Calvin Cycle takes place in bundle sheath cells (spatial separation), reducing O₂ exposure to rubisco. In CAM plants, both processes occur in the same cells but at different times—CO₂ is fixed at night and used during the day (temporal separation), conserving water and minimizing photorespiration in arid environments.
Explain how the compartmentalization within chloroplasts supports the separation of the light-dependent and light-independent reactions.
The thylakoid membrane confines proton accumulation during light-dependent reactions, while the stroma provides a separate space with Calvin Cycle enzymes, preventing interference and increasing efficiency.
Explain the molecular reason why carotenoids travel further on the chromatography paper than chlorophyll.
They are smaller and more soluble in the solvent.
Both processes involve chemiosmosis. Describe how ATP production via chemiosmosis differs in the two.
In photosynthesis, protons build up in the thylakoid lumen and flow into the stroma, produces NADPH; in respiration, protons build up in the intermembrane space and flow into the matrix, requires NADH and FADH2.