Lecture 7 Notes - An Overview of Photosynthesis Photosynthesis Is the process of using sunlight to produce carbohydrate Requires sunlight carbon dioxide

Lecture 7 Notes - An Overview of Photosynthesis...

This preview shows page 1 - 4 out of 11 pages.

An Overview of PhotosynthesisPhotosynthesisIs the process of using sunlight to produce carbohydrate Requires sunlight, carbon dioxide, and water Produces oxygen as a by-product The overall reaction when glucose is the carbohydrate:6 CO26 H2O light energy C6H12O66 O2Photosynthesis contrasts with cellular respirationPhotosynthesis is endergonicReduces CO2to sugarCellular respiration is exergonicOxidizes sugar to CO2Photosynthesis: Two Linked Sets of ReactionsLight-dependent reactionsProduce O2from H2OCalvin cycle reactionsProduce sugar from CO2The reactions are linked by electronsReleased in the light-dependent reactions When water is split to form oxygen gasThen transferred to the electron carrier NADP+, forming NADPHThe Calvin cycle then uses These electrons The potential energy in ATP To reduce CO2to make sugarsThe Structure of the ChloroplastPhotosynthesis occurs in the chloroplastsof green plants, algae, and other photosyntheticorganismsChloroplasts are surrounded by two membranesThylakoidsInternal membranes of chloroplasts that form flattened, vesicle-like structures Form stacks called granaThylakoid membranes contain large quantities of pigmentsThe most common pigment is chlorophyllStromaFluid-filled space between the thylakoids and the inner membrane The Nature of Light EnergyElectromagnetic radiation is a form of energyLightIs a type of energy electromagnetic radiation Acts both particle-like and wave-likePhotons
Background image
As a particle, light exists in discrete packets As a wave, light can be characterized by its wavelengthThe distance between two successive wave crests The Electromagnetic SpectrumThe electromagneticspectrumThe range of wavelengths of electromagnetic radiation Visible lightElectromagnetic radiation that humans can see Each photon and wavelength has a specific amount of energy The energy of a photon of light is inversely proportional to its wavelength Shorter wavelengths such as ultraviolet light Have more energy than longer wavelengths Such as infrared light
Background image
Photosynthetic Pigments Absorb LightPhotons may be absorbed, transmitted, or reflected when they strike an objectPigmentsare Molecules that absorb only certain wavelengths of light There are two major classes of pigment in plant leaves: 1. The chlorophylls(chlorophyll aand chlorophyll b) Absorb red and blue light Reflect and transmit green light 2. The carotenoidsAbsorb blue and green light Reflect and transmit yellow, orange, and red lightEach Pigment Has a Specific Absorption SpectrumAbsorption spectrum Is a graph to study pigments Plots the wavelength of light absorbed by pigment moleculesAn action spectrum Shows the rate of photosynthesis vs. wavelength
Background image
Image of page 4

You've reached the end of your free preview.

Want to read all 11 pages?

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture