Photosynthesis: Chlorophyll, Light Reactions, and Calvin Cycle

What are the two main types of photosynthetic pigments?

Chlorophylls and carotenoids

What type of light does chlorophyll a absorb and reflect?

Absorbs blue and red light, reflects green

What do carotenoids absorb and reflect?

Absorb blue light, reflect yellow, red, and orange

What is the overall equation for photosynthesis?

6CO2 + 6H2O → C6H12O6 + 6O2

How is CO2 used in the photosynthesis experiment?

CO2 is dissolved in sodium bicarbonate

What happens to spinach leaf disks during the experiment?

They sink initially and then float as intercellular spaces fill with oxygen

What do the floating disks indicate in the experiment?

The rate of photosynthesis

What is the role of sodium azide in the experiment?

It inhibits the electron transport chain

What does DCMU inhibit?

Photosystem II

Where do light-dependent reactions occur?

In the thylakoid membranes

What is produced when water is split in photosystem II?

Electrons, H⁺ ions, and O₂ gas

What is the function of ATP in the light-dependent reactions?

ATP is produced by chemiosmosis as electrons move through the electron transport chain

What is NADP⁺ reduced to in the light-dependent reactions?

NADPH

What are the products of the light-dependent reactions?

ATP, NADPH, and O₂

What is the first phase of the Calvin cycle?

Carbon Fixation

What enzyme attaches CO₂ to ribulose bisphosphate (RuBP)?

Rubisco

What is formed when the unstable 6-carbon intermediate splits?

Two molecules of 3-phosphoglycerate (3-PGA)

What happens during the Reduction phase of the Calvin cycle?

3-PGA is phosphorylated by ATP and reduced by NADPH to form G3P

What is the purpose of the Regeneration phase in the Calvin cycle?

To regenerate RuBP so the cycle can continue

How many ATP and NADPH are used to produce one G3P in the Calvin cycle?

9 ATP and 6 NADPH