Big Picture Photosynthesis
What is photosynthesis?
The process by which plants use sunlight to convert carbon dioxide and water into sugars and oxygen.
What organelle carries out photosynthesis?
The chloroplast.
Do light-dependent reactions require light?
Yes.
Does the Calvin cycle require light directly?
No.
What molecule is known as the “energy currency” of the cell?
ATP.
Name one factor that affects the rate of photosynthesis.
Light intensity, temperature, or water availability.
What type of organism performs photosynthesis?
Autotrophs (such as plants, algae, and some bacteria)
What structures inside chloroplasts contain chlorophyll?
Thylakoid membranes.
Where do the light-dependent reactions occur?
In the thylakoid membrane.
What molecule enters the Calvin cycle from the atmosphere?
Carbon dioxide.
What enzyme produces ATP as hydrogen ions pass through it?
ATP synthase.
Why does photosynthesis slow at very high temperatures?
Enzymes begin to lose their shape and function.
What two raw materials are needed for photosynthesis?
Carbon dioxide and water.
Where is the Calvin cycle located?
The stroma of the chloroplast.
What gas is released as a waste product during light-dependent reactions?
Oxygen.
What two molecules from the light-dependent reactions power the Calvin cycle?
ATP and NADPH.
What is an electron transport chain?
A series of proteins that transfer high-energy electrons.
On a photosynthesis graph, what is usually the independent variable?
Light intensity.
What are the two main products of photosynthesis?
Glucose (sugars) and oxygen.
What is a granum?
A stack of thylakoids.
What two energy-carrying molecules are produced during light-dependent reactions?
ATP and NADPH.
What is the main product of the Calvin cycle?
High-energy sugars (glucose).
What molecule carries high-energy electrons from the light reactions to the Calvin cycle?
NADPH.
What type of plants are adapted to hot, dry environments and reduce water loss?
C4 and CAM plants.
Why is photosynthesis essential for most life on Earth?
It produces oxygen and forms the base of most food chains.
Why are membranes important in photosynthesis?
They allow separation of reactions and creation of concentration gradients needed to make ATP.
What molecule is split to replace lost electrons in Photosystem II?
Water (H₂O).
What happens to ADP and NADP⁺ after the Calvin cycle?
They return to the light-dependent reactions to be reused.
What provides the energy that drives ATP synthase?
A hydrogen ion (H⁺) concentration gradient.
How do CAM plants reduce water loss?
They open stomata at night to take in carbon dioxide.