Photosynthesis

Chapter 8

Fig. 10-4

Photosynthesis

• http://bcs.whfreeman.com/thelifewire/content/chp08/0802001.html

Energy in Living Systems

• Autotrophs –

• Heterotrophs -

Chemical Energy

• Energy from the sun must be converted to chemical energy for cells.

• ATP

• ADP

ATP and ADP

Uses of ATP

Uses of ATP

Comparing ATP to Glucose

• Why do cells not store all of their energy in ATP compounds?

• Coins vs. Bills

• Glucose stores 90 times the energy of ATP.

Photosynthesis

What must be taken into the leaf for photosynthesis to occur?

Equation for Photosynthesis

The light energy for photosynthesis is gathered by the pigment chlorophylfound in the cholorplasts of plant cells.

light Calvin lightCalvin

These leaf openings are stomata. What is the function of stomata?

Two main types of Chlorophyl

• Chlorophyl a – absorbs light mostly in the blue-violet and red regions

• Chlorophyl b – absorbs light in the blue and red regions

• Why do leaves

look green? Clorophyl a

Chlorophyl b

Carotene

Where does photosynthesis take place?

• Chloroplasts

Granum

An overview of photosynthesis

• What are the products of the light-dependent reaction?

•What are the products of the light-dependent reaction?

An Overview of Photosynthesis

• What are the products of the Calvin Cycle?

Electron Carriers

• When sunlight excites electrons in chlorophyll –electrons gain much energy– These electrons require carriers

• They accept 2 high energy electrons

– These carriers transport the electrons from chlorophyll to other molecules

• Carrier molecules– NADP+ accepts 2 high energy electrons and a H+ and is

converted to NADPH • The bonds formed traps energy from sunlight in chemical form.

Pod Cast

• http://www.youtube.com/watch?v=g78utcLQrJ4

Electron Transport Chain

Products of the ETC

• The electron transport chain produces:– Oxygen from the breakdown of water– NADPH from NADP+ and H+ (+energy from

electrons)– ATP from ADP in the ATP synthase protein as

H+ pass from one side of the thylakoid membrane to the other

– The NADPH and ATP are used in the Calvin Cycle

Calvin Cycle

Products of the Calvin Cycle

• 6 Carbon Dioxide molecules from the atmosphere are used to make 1 6-carbon sugar molecule.

• The energy from ATP is used and leaves ADP

• The high-energy electrons from NADPH are used and leaves NADP+

• ATP and NADP+ are recycled in the ETC

Factors Affecting Rate of Photosynthesis

• Water

• Temperature– Enzymes used in photosynthesis function

best between 0 and 35 degrees Celsius.

• Light intensity