Photosynthesis

PhotosynthesisPhotosynthesisThe Photosynthesis Song -http://www.youtube.com/watch?v=C1_uez5WX1o Intro Video – http://www.youtube.com/watch?v=zEgIO9Kq2_Y

Photosynthesis the Movie - http://vcell.ndsu.nodak.edu/animations/photosynthesis/movie.htm

ObjectivesObjectives

1. Summarize how energy is captured from sunlight during the light dependent reactions of photosynthesis.

2. Analyze the function of electron transport chains during the light dependent reactions of photosynthesis.

3. Relate the Calvin cycle to carbon dioxide fixation in photosynthesis.

4. Identify three environmental factors that affect the rate of photosynthesis.

Stages of Photosynthesis

Stage 1 Light-dependent reaction

Chlorophyll pigments capture light energy

Stage 3 Light-independent reaction

Reduction of CO2 to glucose:

using ATP + NADPH + H+ to synthesize organic compounds (glucose) from CO2

(carbon fixation); process called Calvin cycle;

Thylakoid membranes

Stroma

© Teachable and Louise Edgeworth. Some rights reserved. http://teachable.net/res.asp?r=6615

Stage 2 Light-dependent reaction

Light energy converted to chemical energy. Production of ATP and NADPH

The Dark Side You just made a bunch of ATP and NADPH from

the light reactions. You now use these electrons and energy to put a

bunch of carbons together to make glucose – this is the job of the Calvin cycle.

The Calvin cycle can be broken down into three phases:

1. Carbon fixation – Putting carbons together.2. Reduction reactions – Adding electrons & energy.3. Regeneration of RuBP – Getting back to the start – it

is a cycle after all.

The Calvin Cycle!

The Calvin Cycle uses ATP and NADPH from the light-dependent reactions and CO2 from the air to make high-energy sugars (glucose)!

What is it?

Glucose

The Calvin Cycle occurs in the stroma of the chloroplast.The Calvin Cycle occurs in the stroma of the chloroplast.

Where does the Calvin Cycle occur?

What parts of the photosynthesis equation are involved in the Calvin Cycle?

CO2 is broken down to create glucose (C6H12O6)

CO2 is broken down to create glucose (C6H12O6)

C6H12O6

Steps of the Calvin Cycle

Calvin Cycle – Carbon Fixation

1. Six CO2 molecules enter the leaf through the stoma and diffuse into the stroma. They are added to a 5 carbon compound (ribulose biphosphate (RuBP)) by an enzyme (rubisco – ribulose bisphosphate carboxylase).

1. Six CO2 molecules enter the leaf through the stoma and diffuse into the stroma. They are added to a 5 carbon compound (ribulose biphosphate (RuBP)) by an enzyme (rubisco – ribulose bisphosphate carboxylase).

2. They are split into twelve 3-carbon compounds

3. ( 3-phosphoglycerate (PGA)).

2. They are split into twelve 3-carbon compounds

3. ( 3-phosphoglycerate (PGA)).

Calvin Cycle – Carbon Fixation

3. Energy from ATP is used to phosphorylate the 3-carbon compounds (PGA) into 1,3-biphosphoglycerate

4. A pair of electrons from NADPH reduces the 1,3-biphosphoglycerate to give G3P – glyceraldehyde 3-phosphate., a 3C

3. Energy from ATP is used to phosphorylate the 3-carbon compounds (PGA) into 1,3-biphosphoglycerate

4. A pair of electrons from NADPH reduces the 1,3-biphosphoglycerate to give G3P – glyceraldehyde 3-phosphate., a 3C

Calvin Cycle – Reduction Reactions

4. Two of the resulting 3-carbon sugars is used to make organic compounds – including GLUCOSE, starch and sucrose – in which energy is stored for later use by the organism.

4. Two of the resulting 3-carbon sugars is used to make organic compounds – including GLUCOSE, starch and sucrose – in which energy is stored for later use by the organism.

Calvin Cycle – Regeneration of RuBP

5. The other ten 3-carbon sugars are used to regenerate the initial 5-carbon compound, (RuBP) thereby completing the cycle. This process consumes 6 molecules of ATP

5. The other ten 3-carbon sugars are used to regenerate the initial 5-carbon compound, (RuBP) thereby completing the cycle. This process consumes 6 molecules of ATP

Calvin Cycle – Regeneration of RuBP

Review of Calvin Cycle

Where does the Calvin Cycle occur?

In the stroma of the chloroplast!

What goes into the Calvin Cycle?

ATP and NADPH are used for energyCO2 is broken apart to create C6H12O6

Animation of Overview of Photosynthesishttp://wps.prenhall.com/wps/media/

objects/486/498596/CDA7_1/CDA7_1d/CDA7_1d.htm

Factors that Affect Photosynthesis

Photosynthesis is directly affected by environmental factors such as:

1. The intensity of light

2. The concentration of carbon dioxide

3. Temperature.

PHOTOSYNTHESIS QUIZ15 points

1. Where in a plant cell does photosynthesis occur?

2. What are the 2 stages of photosynthesis and where do they occur?

3. Why are plants green?

4. What is the balanced equation for photosynthesis?

5. What are the reactants and products of the light dependent reactions?

6. What are the reactants and products of the Calvin Cycle?

7. What are two reasons we depend on plants for our survival?

Review1. Summarize how photosynthetic organisms

capture the energy in sunlight.2. Compare the roles of water molecules and

hydrogen ions in electron transport chains.3. Describe the role of the Calvin cycle in

photosynthesis.4. Critical Thinking Organizing Information

Make a table in which you identify the role of each of the following in photosynthesis: light, water, pigments. ATP. NADPH. and carbon dioxide.

5. Critical Thinking Inferring Relationships What combination of environmental factors affects the rate of photosynthesis?6. Standardized Test Prep During photosynthesis, plants store energy inA ADP.B carbon dioxide.C 3-carbon sugars.D water.