AO1 WJEC Photosynthesis and Light-dependent Reactions Quiz

Where do the light-dependent reactions of photosynthesis take place, precisely?

• In the stroma of the chloroplast

• In the thylakoid membranes of the chloroplast

• In the mitochondria

• In the nucleus

What is the energy transformation in the light-dependent reactions?

• Chemical → Light

• Heat → Chemical

• Light → Chemical

• Electrical → Mechanical

What is the correct sequence of events in the light-dependent reactions?

• Water uptake → Starch production → ATP synthesis

• CO₂ fixation → Proton gradient → NADH formation

• Light absorbed by chlorophyll → Photolysis of water → Electron transport → Proton gradient → ATP and NADPH formed

• O₂ absorbed → Glucose breakdown → ATP synthesis

What is the name of the process in the light-dependent reaction where light energy is used to form ATP and NADPH?

• Carbon fixation

• Photophosphorylation

• Glycolysis

• Chemiosmosis

In the Hill Reaction, how could you investigate whether light is necessary using DCPIP?

• Use chloroplasts in the dark and observe pH changes

• Use isolated chloroplasts, add DCPIP, expose one sample to light and one to dark – DCPIP turns colourless in light (reduced), stays blue in dark (oxidised)

• Boil chloroplasts and measure heat change

• Add glucose and see if it binds DCPIP

Why must the solution used to isolate chloroplasts be ice-cold?

• To speed up enzyme reactions during isolation

• To increase membrane permeability

• To slow down enzyme activity and prevent damage to chloroplasts

• To activate photosynthesis in the dark

Why must the solution used to isolate chloroplasts be isotonic?

• To dissolve chloroplast membranes

• To prevent water movement that could cause chloroplasts to burst or shrink

• To maintain high salt concentration for ATP production

• To enhance oxygen release from the chloroplasts

Why must the solution used to isolate chloroplasts be buffered?

• To break down the thylakoid membrane

• To maintain a stable pH and prevent enzyme denaturation

• To increase the acidity for better light absorption

• To change chloroplast color for easier observation

What is the name of the process that splits water?

• Electrolysis

• Photolysis

• Hydrolysis

• Osmosis

Where does photolysis occur precisely?

• Stroma

• Outer chloroplast membrane

• Inside the thylakoid lumen, at Photosystem II

• Mitochondrial membrane