Photosynthesis Quiz 2

ATP breakdown in the chloroplast provides energy for which step of photosynthesis?

• Active transport of H⁺ into thylakoid

• Diffusion of CO₂ into stroma

• Passive return of H⁺ through ATP synthase

• Splitting of water molecules

Which molecule is produced when ATP loses a phosphate during photosynthesis?

• ATPase

• ADP + Pi

• NADPH

• RuBP

The rate of ATP breakdown in the light phase is directly increased by:

• Lower CO₂ concentration

• Higher light intensity

• Decreased temperature

• Increased O₂ concentration

Which factor DOES NOT affect the rate of photosynthesis?

• Light intensity

• Water availability

• Chlorophyll color

• CO₂ concentration

As temperature rises above the optimum for a plant, what happens to ATP production?

• Increases indefinitely

• Declines due to enzyme denaturation

• Remains constant

• Becomes independent of light intensity

At low CO₂ levels, the rate of photosynthesis is limited because:

• ATP cannot break down

• RuBP cannot fix enough CO₂

• Water uptake stops

• Light reactions cease

Which of these is a raw material whose availability directly affects ATP breakdown in photosynthesis?

• Oxygen

• Water

• Glucose

• Starch

In a controlled experiment, increasing light intensity while keeping CO₂ and temperature constant will:

• Decrease ATP usage

• Increase rate of ATP breakdown

• Increase RuBP regeneration rate

• Decrease O₂ evolution

Which phrase best describes the role of ATP in photosynthesis?

• Storage molecule

• Immediate energy carrier

• Long-term energy store

• Structural component

If CO₂ concentration is doubled, but light intensity is very low, the rate of ATP breakdown will be:

• Limited by light, so remain low

• Double

• Halve

• Unchanged