GEN. BIO 1

• Light-dependent reaction


  One of the two types of Photosynthesis
• Light-dependent reaction


  • Takes place in the Thylakoid Membrane of membrane called Chloroplasts
  • Uses H2O and Energy from Sunlight
  • Produces ATP (Energy Storage) and NADPH (electron carrier) and by-product O2
• Photochemical reactions


  1. Needed materials: Light - Energy, pigments (chlorophyll)

  2. End products: Electrons
• Electron transport


  1. Needed materials: Electrons, NADP+, H2O and Electron Acceptors

  2. End products: NADPH, O2
• Chemiosmosis


  1. Needed materials: Proton Gradient, ADP+P, ATP synthase

  2. End products: ATP
• Electromagnetic (EM) spectrum


  • Radio waves
  • Microwaves
  • Infrared waves
  • Visible light
  • Ultraviolet waves
  • X-rays
  • Gamma rays
• Radiation


  Energy that travels and spreads out as it goes
• Light moves in waves, in energy units called PHOTONS
• Energy of Photons


  Inversely proportional to its wavelength
• Photosynthesis occurs in Leaves
• Photosynthesis uses the right amount of energy for biological reactions
• NM


  Used to measure wavelength
• EV


  Used to measure energy
• Violet has a shorter wavelength than red
• P680


  Wavelength capacity to absorb up to 680
• P700


  Wavelength capacity to absorb up to 700
• Thylakoid membrane

  • Has 2 parts: thylakoid membrane and thylakoid space / lumen
• Chlorophyll

  Pigment molecule that absorbs wavelengths of light
• Most pigments absorb only some wavelengths since they reflect or transmit to other wavelengths
• Absorption spectrum


  The pigments in chloroplasts are capable of absorbing various portions of visible light

  
• Photosynthetic organisms differ in the type of Chlorophyll they contain
• Chlorophyll A


  Primary photosynthetic pigment that drives photosynthesis
• Chlorophyll A absorbs at different wavelengths, extending the range of light useful for photosynthesis
• Accessory pigments


  • Carotenoids
  • Anthocyanins
  • Xanthophylls
• Chlorophyll molecules


  • Located in the thylakoid membrane
  • Mg+ in the center
  • Harvest energy (photons) by absorbing certain wavelengths (blue and red are most important)
  • Plants are green because the green wavelength is reflected not absorbed
• Structure of chlorophyll

  • Head - a flat hydrophilic head called porphyrin rings with a magnesium atom at its center. Different chlorophylls differ in groups attached to the porphyrin.
  • Tail - a lipid-soluble hydrocarbon tail
• Photosystem I and II


  • They have the same structure
  • Photosystem II is the first to react, Photosystem I is the one who discovered
  • Photosystem II is also known as P680, Photosystem I is also known as P700
  • Will react if there are electrons
• Electron carriers or acceptors

  • Plastoquinone (Pq)
  • Plastocyanin (Pc)
  • Cytochrome
• Ferredoxin (Fd)


  Electron acceptors or carriers
• Ferredoxin NADP+ Reductase


  Electron acceptors and enzyme
• ATP Synthase


  Enzyme: function is to speed up chemical reactions
• Photosystem II


  • Complex network of chlorophyll
  • Accessory pigments: green
  • Reaction Center: chlorophyll a (P680) it has electrons
  • Primary electron acceptor: dito aakyat yung energized electrons
• Plastoquinone (Pq)


  Kukuhanin from electron acceptor yung energy, It will pass the energy to Cytochrome
• Cytochrome B6F Complex


  There are Hydrogen ions in the stroma, The energy in the cytochrome attracts the hydrogen ions to enter the thylakoid space/lumen
• Plastocyanin (Pc)


  The electron has no energy left, Pass the electron to the primary reaction center of Photosystem I
• Photosystem I -P700


  Will pass the electron to NADP+ Reductase
• Ferredoxin NADP+ Reductase


  Will donate electron to NADP+ and will form NADPH: highly energized electrons
• Water (H2O)


  This is where the electrons came from
• Photolysis


  A chemical reaction in which an (in)organic chemical is broken down by photons
• Proton Gradient


  Hydrogen ions na ipon-ipon