Photosynthesis

Bell Work Explain why the pigments in the chlorophyll extract moved up the paper and the pigments in the red cabbage extract did not.

Objectives List the stages of the photosynthetic process Identify the inputs and outputs of light dependent and independent photosynthetic reactions Explain why Calvin cycle is light independent

Key Terminology Saturation Thylakoid Membrane Stroma Calvin cycle Photosynthetic electron transport Glyceraldehyde-3-phosphate

Chloroplast -Site of Photosynthesis in Plants Structure of the chloroplast Outer membrane double membrane Thylakoid membranes internal membranes site of photosynthetic electron transport Stroma thick fluid that surrounds the thylakoid membranes site of Calvin cycle

Stages of Photosynthesis Stage 1: Absorption of sunlight Stage 2: Light-dependent reactions involving photosynthetic electron transport Stage 3: Light-independent reactions involving the Calvin cycle

Absorption of Light The rate of photosynthesis changes with light intensity As the light intensity increases the photosynthetic rate increases until it saturates with light (when the curve plateaus) At the point of saturation the pigments cannot absorb any more light light intensity

Stage 2 Photosynthetic Electron Transport (Light-Dependent Reactions) Location: Thylakoid membrane Function: Converts the light captured to chemical energy Captured light excites electrons that move through the electron transport chain Energy from the movement of electrons is used to make chemical energy ATP and NADPH

Photosynthetic Electron Transport

Light Dependent Reaction Animation

Why is it called the Light Dependent Reactions? Light directly interacts with the Electron Transport Chain Light causes the electrons to move through the chain

PROPERTY OF PIMA COUNTY JTED, 2010 Think-Pair-Share Why can’t humans live without photosynthetic electron transport? 3. Think-pair-share teacher presents a question teacher gives wait time for student to form answer teacher instructs students to share their answer with a partner teacher calls on non-volunteers to share with the class PROPERTY OF PIMA COUNTY JTED, 2010 3

Photosynthetic Electron Transport Inputs: Light, H20, ADP, and NADP+ Outputs: ATP, NADPH, O2 ATP and NADPH used by the light independent reactions to make food for the plant

Stage 3 Calvin cycle (Light Independent Reactions) Location: Stroma Function: To produce energy rich sugar glyceraldehyde-3-phosphate that provides carbon skeletons to make glucose Inputs: CO2, ATP, NADPH Outputs: glyceraldehyde-3-phosphate, ADP, NADP+ Remaining carbon used to keep the cycle going

Calvin Cycle

Light Independent Reactions Animation

Purpose of CO2 Calvin Cycle “fixes” CO2 CO2 provides carbon for the production of glucose

Why is the Calvin Cycle called the Light Independent Reactions? Because light does not interact directly with the cycle

PROPERTY OF PIMA COUNTY JTED, 2010 Think-Pair-Share Global Warming is due to the increase in CO2 due to burning fossil fuels. To combat this, environmentalists suggest planting trees. Why? 3. Think-pair-share teacher presents a question teacher gives wait time for student to form answer teacher instructs students to share their answer with a partner teacher calls on non-volunteers to share with the class PROPERTY OF PIMA COUNTY JTED, 2010 3

PROPERTY OF PIMA COUNTY JTED, 2010 3 Minute Paper Explain the relationship between photosynthetic electron transport and the Calvin cycle. Be prepared to share. 29. Minute paper or Quick Write teacher provides a prompt from the lesson students have one minute to write down a summary of the key points students compare with a partner teacher uses a strategy to check all PROPERTY OF PIMA COUNTY JTED, 2010 20

Answer the following questions in complete sentences and IYOW Draw two rectangles. Label one rectangle PSET and the other rectangle Calvin Cycle. Show the inputs and outputs for each biochemical process. Identify the products that are outputs for PSET and Inputs for Calvin cycle Explain why PSET is light dependent and Calvin Cycle is Light independent. What happens to the photosynthetic rate when the plant becomes saturated with light? What is the purpose of CO2? Explain where PSET and Calvin cycle are located within the chloroplast.