Photosynthesis

Energy and Life Autotrophs and Heterotrophs Autotroph (producer) – makes its own food Heterotroph (consumer) – obtains energy from eating other organisms

Autotrophs and Heterotrophs

Chemical Energy and ATP ATP (adenosine triphosphate) is the principle chemical compound used to store and release energy ATP has three parts: Adenine Ribose 3 phosphate groups

ADP ADP (adenosine diphosphate) also has 3 parts: Adenine Ribose 2 phosphate groups

Storing and Releasing Energy

ATP-ADP Cycle of Energy Energy is released by breaking the chemical bond between the 2nd and 3rd phosphate (ATP becomes ADP) Energy is stored by bonding a 3rd phosphate to ADP (ADP becomes ATP)

?????? All living things require energy, but where does the energy come from? But I can’t get energy directly from the sun……. And how do plants store the energy they get?

The Photosynthesis Equation light 6C02 + 6H20  C6H1206 + 602 Photosynthesis uses the energy of sunlight to convert water and carbon dioxide into high-energy sugars and oxygen light Carbon dioxide + water  sugars + oxygen

Pigments Pigments are light absorbing molecules. The principle pigment is chlorophyll. Which organelle contains chlorophyll?

Parts of a Chloroplast

Two Reactions: Light-dependent and light-independent (Calvin Cycle) Light dependent reactions take place in the thylakoid membranes. Light independent reactions (Calvin cycle) takes place in the stroma, the region outside the thylakoids.

Light-dependent Reactions This reaction requires light. Oxygen gas is produced. ADP and NADP+ are converted into the energy carriers ATP and NADPH.

Light-independent Reactions The Calvin Cycle does not require light (light independent.) Carbon dioxide along with the energy from ATP and NADPH form sugars, lipids, amino acids and other compounds.

Photosynthetic Reactions

Location Requires Produces Light Dependent Reactions Light Independent Reactions (Calvin Cycle) Location Thylakoid membranes Stroma Requires Light Water Carbon Dioxide ATP NADPH Produces Oxygen High Energy Sugars

Factors Affecting Photosynthesis Water shortage – slows or even stop photosynthesis Temperature – enzymes necessary for photosynthesis work best at temperature between 10o C and 20o C (50o F and 68o F) Light intensity – increasing intensity increases rate of photosynthesis