Light-Independent Reaction

Question 1

What are the four main steps of the Calvin Cycle

Answer 1

**1. Carbon Fixation: **The RuBisCO enzyme catalyzes the attachment of carbon dioxide to RuBP, forming an unstable 6-carbon compound.
2. Reduction: ATP and NADPH from the light reactions are used to convert the 6-carbon compound into two molecules of 3-phosphoglycerate.
3. Regeneration of RuBP: ATP is used to regenerate RuBP from the remaining molecules, ensuring the cycle can continue.
4. Formation of G3P: Some of the G3P molecules produced are used to synthesize glucose and other carbohydrates, while others regenerate RuBP.

Question 2

How many CO2 molecules are required to make one glucose molecule?

Answer 2

To make one glucose molecule, six molecules of carbon dioxide are required in the Calvin Cycle.

Question 3

How many CO2 molecules are required to regenerate RuBP?

Answer 3

To regenerate one molecule of RuBP, five molecules of carbon dioxide are needed.

Question 4

What enzyme is responsible for binding RuBP and CO2?

Answer 4

RuBisCO (Ribulose-1,5-bisphosphate carboxylase/oxygenase).

Question 5

How is the stomata of the leaf able to open and close?

Answer 5

The opening and closing of stomata in the leaf are regulated by guard cells. When guard cells take in potassium ions, they swell and create a turgor pressure that causes the stomata to open.

Question 6

At what points of the day will it stay open?

Answer 6

stay open during the day when photosynthesis occurs and close at night to converse water.

Question 7

Does temperature have an effect on the opening/closing of the stomata?

Answer 7

yes, higher temps can lead to increased transpiration and water loss, causing the stomata to close preventing dehydration

Question 8

Why is lower temps better?

Answer 8

lower temperatures can reduce transpiration and help maintain turgor pressure, keeping the stomata open.