Biology photosynthesis

• The Calvin cycle uses ATP and NADPH produced during the light-dependent reactions to power the synthesis of glucose.
• The membrane of a thylakoid sits inside of a chloroplast.
• The thylakoid membrane loops around to form the thylakoid.
• The lumen is on the inside of the thylakoid membrane.
• The stroma is on the outside of the thylakoid membrane.
• The thylakoid membrane is a standard membrane that is found in many organelles.
• The thylakoid membrane has a phospho-bilipid layer.
• Protons can cross the thylakoid membrane using the energy from electrons going to lower energy states.
• The outside of the thylakoid membrane is hydrophilic because it operates well in a polar environment.
• The insides of the thylakoid membrane are non-polar or hydrophobic.
• Complexes span across the thylakoid membrane, including photosystem II, photosystem I, and ATP synthase.
• The electrons get excited first in the chlorophyll of photosystem II.
• The electrons get less and less excited as they get handed off from one complex to another complex, ending up in photosystem I.
• The first place where the electrons get excited is in the chlorophyll of photosystem II.
• The electrons get excited again in photosystem I.
• Plastocyanin is a component of photosystem I.
• Plastoquinone and cytochrome B6F complex are components of photosystem II.
• Electrons are comfortable in water and in chlorophyll A, and they are even more comfortable in photosystem I.
• Another photon or another set of photons coming in from 93 million miles away can excite the chlorophyll in photosystem I, which excites the excited electron, releasing energy.
• The excited electron in plastoquinone transfers to the cytochrome B6F complex, which is a slightly lower energy state.
• The excited electron in chlorophyll A goes to a high energy state and then transfers to the primary electron acceptor, pheophytin, which is a chlorophyll A molecule.
• The excited electron in the cytochrome B6F complex transfers to the plastocyanin complex, which is a slightly lower energy state.
• A photon excites electrons in chlorophyll A or other pigment molecules, which can then excite the photophorylation A directly or excite the electrons in chlorophyll A directly.
• The excited electron in pheophytin is at a very high energy state and then transfers to the plastoquinone, which is a slightly lower energy state.
• The excited electron in the plastocyanin complex transfers to photosystem I, which is an even lower energy state.
• Pheophytin is part of the photosystem complex and the electron can jump from the chlorophyll to the pheophytin.
• The electrons get handed off, the whole time that energy is being used to transfer hydrogen protons from the stroma into the lumen.
• Photosystem II is where everything starts from.
• The electron can still be transferred to other things and release energy.
• Once the hydrogen and the electron meet, the hydrogen will be on the other side, able to freely go away again.
• Through chemiosmosis, the electron eventually goes through the ATP synthase channel, turns around this part of this protein complex or enzyme complex and actually generates ATP.
• The electron can drive the proton pump and eventually ends up in the NADPH at a fairly high level of energy still.
• Water gets oxidized by the water oxidation on photosystem II and that electron ends up and replaces the electron in the chlorophyll.
• As the electron goes down to NADPH, you are pumping protons across the membrane.
• The electron wants to go into a lower energy state, so it'll rotate around, allowing the hydrogen to cross the barrier.
• The electron gets transferred from one molecule to another, gets excited again, and keeps going all the way, eventually being accepted by the NAD+ to become NADPH.
• In the electron transport chain video, when I talk about cellular respiration, I give a visual concept of how this actually might happen.
• The electrons going from one molecule to another can help pump hydrogen through.
• The electron starts off at a low energy state and the only way this happens is by energy from light.
• In a gross oversimplification, the electron on a pheophytin molecule can attract a hydrogen proton to rotate around and cross the barrier.