Photosynthesis: Light-Independent Reactions

What is the final electron acceptor in the electron transport chain?

Chlorophyll is an electron source in the electron transport chain.

What are the waste products generated from cellular respiration?

The organelle responsible for ATP synthesis in plants is the ______.

Match the following components with their correct characteristics:

Which enzyme catalyzes the reaction of fixing carbon dioxide in the Calvin Cycle?

The Calvin Cycle only occurs in the presence of light.

What three phases make up the Calvin Cycle?

The product of the reduction phase in the Calvin Cycle that can be used to form glucose is called _____.

Match the phase of the Calvin Cycle with its description:

What is the overall net equation for the Calvin Cycle?

The Calvin Cycle produces three-carbon organic molecules from inorganic carbon.

The unstable six-carbon compound formed during carbon fixation breaks down into two identical three-carbon compounds called _____.

Light-Independent Reactions (Calvin Cycle)

The light-independent reactions occur in the stroma of chloroplasts
They use ATP and NADPH, produced during the light-dependent reactions
The reactions convert inorganic carbon (carbon dioxide) into organic carbon (carbohydrates)
This process is also known as carbon fixation or the Calvin cycle
The cycle can occur in the presence or absence of light

The Calvin Cycle Phases

Phase 1: Carbon Fixation
- Carbon dioxide is attached to a five-carbon molecule called RuBP
- This forms an unstable six-carbon molecule that immediately splits into two three-carbon molecules called 3-PGA
- The process is catalyzed by the enzyme RuBisCo
Phase 2: Reduction
- 3-PGA is converted into glyceraldehyde-3-phosphate (G3P)
- ATP provides the energy and NADPH provides the electrons for this reduction reaction
- Some G3P molecules leave the cycle to be used to make glucose and other carbohydrates
Phase 3: Regeneration of RuBP
- Most of the G3P is used to regenerate RuBP
- ATP is needed for the regeneration steps
- The regeneration of RuBP is crucial to keep the cycle going.

Net Equation for the Calvin Cycle

The overall equation for the Calvin cycle summarizes the process of fixing carbon dioxide from the atmosphere and convert it into energy-rich organic molecules while also regenerating the RuBP needed to start the cycle again.
6 CO2 + 18 ATP + 12 NADPH + 10 H2O → 2 G3P (glyceraldehyde-3-phosphate) + 16 Pi + 18 ADP + 12 NADP+

Overview of Photosynthesis

The overall process of photosynthesis has two main stages: light-dependent reactions and light-independent reactions
Light-dependent reactions produce the energy-carrier molecules ATP and NADPH
The light-independent reactions use this energy for carbon fixation, converting carbon dioxide from the atmosphere into glucose and other carbohydrates.

This quiz covers the light-independent reactions of photosynthesis, specifically focusing on the Calvin cycle. Understand the phases of carbon fixation, reduction, and regeneration in the stroma of chloroplasts. Test your knowledge on the processes involved and the role of ATP and NADPH.