Photosynthesis

Light Reactions and Calvin Cycle

Review• Autotrophs make their own food by trapping light.

What’s this called? Write out the formula:

• 6CO2 + 6H2O + light energy ---> C6H12O6 + 6O2

• Animals harvest the energy through a process called what? Write out the formula:

• C6H12O6 + 6O2 ---> 6CO2 + 6H2O + ATP

Review

• If two plants had exactly the same growing conditions (soil, nutrients, temperature, etc), but one had only green light and the other had only blue light, which one would grow better? Why? Discuss with your neighbor after you write down with your own answer.

Objectives

1. Describe the makeup of a chloroplast

2. Understand the light reactions and Calvin Cycle

Photosynthesis:What’s happening inside the chloroplast

• Chloroplast:– Organelle where

photosynthesis takes place

• Two reactions taking place:

1. Light Reactions

2. Calvin Cycle

Where Photosynthesis Happens

• Thylakoid: – pancake structure,

membrane, light reactions

• Granum: – stack of thylakoids

The chloroplast

• Thylakoids have a very high surface area to volume ratio.

• Why is this important?

Light ReactionsInside the Thylakoid Membrane

1. Chlorophyll captures light energy

2. Electrons removed from water

3. 02 (waste) escapes through stomata

4. Chloroplasts make energy (NADHP & ATP)

Calvin Cycle:A Sugar Factory

• Inputs: – C02 from the air &

energy from light reactions

• Does NOT use light• Produces sugar

Review

• What are the inputs and outputs of the light reactions?– Inputs: H2O and light– Outputs: O2 and ATP

• What are the inputs and outputs of the Calvin cycle?– Inputs: CO2 and ATP– Outputs: glucose