Photosynthesis Process for High School, Biology

Here I explain the photosynthesis process.

1. PHOTOSYNTHESIS

2. VOCABULARY Pigment Photosystem Wavelength : is the distance from one wave peak to the next . Chlorophyll Photon : Light is composed of small particles , or packets of energy called photons . The energy of a photon is inversely proportional to its wavelength : shorter has more energy per photon than larger . White light Photolysis Rubisco . Aerobic respiration Anaerobic respiration Fermentation Glycolysis Krebs cycle NADH FADH2

3. Visible light represents a very small portion of a range radiation called the electromagnetic spectrum . A wavelenght is the distance from one wave peak to the next. The portion of electromagnetic spectrum from 380 to 760 nm is called the visible spectrum because human can see it. LIGHT PROPERTIES

4. Light s composed of small particles, or packets of energy called photons. The energy of a photon is inversely proportional to its wavelength: shorter has more energy per photon than larger. Radiation with wavelengths longer than visible light does not have enough energy to excite biological molecules. Radiation with wavelengths shorter than visible light is so energetic that it disrupts the bonds of many biological molecules.

5. PIGMENTS Thylakoids membranes contain several kinds of pigments, which are substances that absorb visible light. Chlorophyll , the main pigment of photosynthesis, absorbs light primarily in the blue and red regions of the visible spectrum. The most important chlorophyll a (green), is the pigment that inititates the light-dependent reactions of photosyntheis. Chlorophyll b (yellow-green) is an accesory pigment that also participates in photosynthesis. Carotenoids (yellow and orange) absorb different wavelengths, thereby expandes the spretrum of light that provides energy.

6. CHLOROPLASTS Chloroplasts lie mainly inside the leaf in the mesophyll, a layer with many air spaces and very high concentration of water vapor. The interior of the leaf exchange gases with th eoutside through microscopes pores, called stomata . Each mesophyll cell has 20 to 100 chloroplasts.

7. PHOTO LIGHT-DEPENDENT REACTIONS Light energy is converted to chemical energy in thylakoids. Chlorophyll captures light energy, transfer electrons to an acceptor molecule. Released molecular oxygen for H 2 O split. Some energy of the energyzed elctrons is used to form ATP and NADPH. SYNTHESIS CARBON FIXATION REACTIONS Depend on the products of light-dependent reactions, and take place in the stroma of chloroplasts. ATP and NADPH molecules produced during light-dependent reactions transfer their energy to chemical bonds in carbohydrates. Fix carbon atoms from CO 2 to existing skeletons of organic molecules.