Calvin Cycle and Light Reactions

The video explains the dark reactions in photosynthesis, focusing on the Calvin Cycle. It highlights the role of ATP and NADPH from light reactions in carbon fixation, converting CO2 into glucose. The process occurs in the stroma, facilitated by the enzyme RuBisCo. The Calvin Cycle is a series of reactions that regenerate RuBP and produce PGAL, which can form glucose. The video clarifies that dark reactions are light-independent, not occurring in darkness.

What is the primary role of photons in the light reactions of photosynthesis?

• To break down glucose

• To excite electrons in chlorophyll

• To absorb carbon dioxide

• To produce oxygen directly

Which molecule acts as the final electron acceptor in the light reactions?

• Water

• NADP+

• Oxygen

• Carbon dioxide

Why are the dark reactions called 'light-independent reactions'?

• They depend on moonlight

• They occur only at night

• They do not require light to proceed

• They produce light

What molecule does CO2 react with in the Calvin Cycle?

• RuBP

• Glucose

• NADPH

• ATP

How many PGAL molecules are used to regenerate RuBP in the Calvin Cycle?

• 6

• 10

• 12

• 2

What is the main product formed from two PGAL molecules?

• NADPH

• ATP

• Glucose

• Oxygen

Where does the Calvin Cycle take place within the chloroplast?

• Stroma

• Thylakoid membrane

• Nucleus

• Cytoplasm

What is the role of the RuBisCo enzyme in the Calvin Cycle?

• To produce ATP

• To facilitate the reaction between CO2 and RuBP

• To generate oxygen

• To break down glucose

What is carbon fixation?

• The conversion of carbon dioxide into a solid form

• The absorption of carbon dioxide by water

• The release of carbon dioxide

• The breakdown of carbon compounds

What is the significance of the Calvin Cycle being a cycle?

• It produces light

• It does not require enzymes

• It continuously regenerates RuBP

• It only occurs once