5.1 Photosynthesis Overview Unit 5: Cell Energy 5.1 Photosynthesis Overview

The Energy Cycle Photosynthesis and Cellular Respiration are cyclical of each other. Photosynthesis is the process to create the energy from sunlight. The energy is stored in the chemical bonds of sugars. Cellular respiration is how living organisms use that energy. Plants and Animals break the bonds to use the energy.

Photosynthesis Uses energy from sunlight to convert water and carbon dioxide (reactants) into high energy sugars and oxygen (products) This means that sunlight is the ultimate source of energy for all life on Earth.

Structure of Carbohydrates Simple = Monomer Complex = Polymer Monosaccharide: simple ring sugars Ex: glucose and fructose Formula: CHO in a 1:2:1 ratio Ex: Glucose- C6H12O6 Disaccharide: two monosaccharides combined. Ex: sucrose, maltose, and lactose Polysaccharides: polymers (long chains of repeating units) of monosaccharides These are energy storing molecules (when you create a bond, it stores energy) Ex: starch (plants) and glycogen (animals) Structural: cellulose (found in plants)

Function of Carbohydrates Source of short-term energy Structural materials in organisms.

Adenosine Triphosphate: ATP ATP is an organic molecule that contains high energy phosphate bonds. It consists of one adenine, one sugar ribose, and three phosphates. We can remove a phosphate to release energy. The result is Adenosine Diphosphate or ADP. We can add a phosphate to ADP to store energy. The result is ATP!

Overall Equation Products Reactants

Reactions in Photosynthesis Light Dependent Reactions Light Independent Reactions Require direct involvement of light Use sun’s energy to produce ATP Takes place in the thylakoids Water is required as a sources of electrons and hydrogen ions Oxygen is released No Light is required ATP and NADPH are used to make sugars Takes place in the stroma Carbon dioxide is required

Where Photosynthesis Occurs The Chloroplast is the organelle where photosynthesis occurs Structure: Contain an inner and outer membrane Thylakoid: saclike photosynthetic membranes Grana: Interconnected stacks of thylakoid Stroma: Fluid outside the thylakoid

Pigments Chloroplasts contain pigments! Pigments are light-absorbing molecules that gather the sun’s energy Pigments are located in the thylakoid membranes Sunlight is a mixture of different wavelengths our eyes perceive as white Colors include red, orange, yellow, green, blue, indigo, and violet The sun’s energy travels to Earth as light The pigments in chloroplasts absorb the different wavelengths of light!

Chlorophyll A plant’s principle pigment Chlorophyll absorbs visible light especially well Chlorophyll absorbs blue-violet and red wavelengths of light best Chlorophyll reflects green wavelengths, causing plants to appear green

Fall Colors Plants also contain red and orange pigments, such as carotene, that absorb light in other regions of the spectrum. As temperatures drop later in the year, chlorophyll pigments break sown first, leaving red and orange pigments to be seen