Photosynthesis Study Guide 2026
Everything you need to pass the Photosynthesis exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📚 Photosynthesis Topics to Study (69)
✍️ Sample Photosynthesis Questions & Answers
1. What would be the immediate effect on the Calvin cycle if the stroma suddenly became more acidic (lower pH)?
Calvin cycle enzymes, like most enzymes, have an optimal pH near neutral; acidification of the stroma would reduce their catalytic efficiency.
2. Which human activity most directly increases the amount of light available for aquatic photosynthesis in a lake?
Removing shading trees allows more solar radiation to penetrate the water, temporarily boosting photosynthesis by aquatic plants.
3. Which of the following plants is a classic example of CAM photosynthesis?
Cacti like Opuntia are classic CAM plants adapted to desert environments; they fix CO2 at night and keep stomata closed during hot days to conserve water.
4. How does the structure of a leaf affect photosynthesis?
Leaves are structurally adapted to maximize photosynthesis. A larger surface area allows for greater light absorption, while the presence of numerous chloroplasts within the leaf cells provides more sites for the photosynthetic reactions to occur. These adaptations collectively increase the efficiency of converting light energy into chemical energy.
5. Which classic experiment by Engelmann demonstrated that different wavelengths of light drive photosynthesis at different rates?
Engelmann split light into a spectrum across algae and used oxygen-seeking bacteria to detect where photosynthesis was highest, revealing the action spectrum in 1882.
6. Oligomycin blocks the F0 channel of ATP synthase. What happens to the proton gradient?
Blocking proton re-entry through ATP synthase causes the gradient to build up, eventually back-inhibiting the ETC and stalling electron flow.