What are the 5 steps of light-dependent reactions?
Terms in this set (7)
- (1st Time) Energy is absorbed from the sun.
- Water is broken down.
- Hydrogen ions are transported across the thylakoid membrane.
- (2nd Time) Energy is absorbed from the sun.
- NADPH is produced from NADP+.
- Hydrogen ions diffuse through the protein channel.
- ADP becomes ATP.
What is the correct order of steps in the light-dependent reactions?
Here are the basic steps:
- Light absorption in PSII. When light is absorbed by one of the many pigments in photosystem II, energy is passed inward from pigment to pigment until it reaches the reaction center.
- ATP synthesis.
- Light absorption in PSI.
- NADPH formation.
What are photosystem 1 and 2?
Photosystem I (PS I) and photosystem II (PS II) are two multi-subunit membrane-protein complexes involved in oxygenic photosynthesis. The main difference between photosystem 1 and 2 is that PS I absorbs longer wavelengths of light (>680 nm) whereas PS II absorbs shorter wavelengths of light (<680 nm).
What is produced in cyclic Photophosphorylation?
Under certain conditions, the photoexcited electrons take an alternative path called cyclic electron flow, which uses photosystem I (P700) but not photosystem II (P680). This process produces no NADPH and no O2, but it does make ATP. This is called cyclic photophosphorylation.
What are the 6 steps of light reaction?
Terms in this set (6)
- Sunlight strikes the chlorophyll molecules in the thylakoid membranes.
- Light energy is transferred to the chlorophyll’s electrons.
- The electrons pass from the chlorophyll to an electron transport chain.
- The energy lost by electrons as they pass through the electron transport chain is used to make ATP.
What is difference between oxidative phosphorylation and photophosphorylation?
Oxidative Phosphorylation is the process that produces ATP using enzymes and oxygen. It is the last stage of aerobic respiration. Photophosphorylation is the process of ATP production using sunlight during the photosynthesis.
What is Step 1 of the light reactions?
Step 1: Units of sunlight, called photons, strike a molecule of chlorophyll in photosystem II of the thylakoid membrane. The light energy is absorbed by two electrons (2 e-) in the chlorophyll molecule, giving them enough energy to leave the molecule.
What is photophosphorylation?
Photophosphorylation is the conversion of ADP to ATP using the energy of sunlight by activation of PSII. This involves the splitting of the water molecule in oxygen and hydrogen protons (H+ ), a process known as photolysis.
Is photophosphorylation a respiratory pathway?
Photophosphorylation is another mechanism of ATP synthesis that uses an ETC to generate a PMF, which then drives ATP synthase (Fig. 4 ). However, ETCs associated with photophosphorylation are not respiratory.
How does energy transformation via photophosphorylation work?
Energy transformation via photophosphorylation need not involve linear electron flow from an initial donor to a terminal acceptor. Instead, electrons can be repeatedly energized and cycled through an ETC in a process called cyclic photophosphorylation.
Where does the process of cyclic photophosphorylation take place?
This process usually takes place in the thylakoid membrane and uses Photosystem I and the chlorophyll P700. During cyclic photophosphorylation, the electrons are transferred back to P700 instead of moving into the NADP from the electron acceptor. This downward movement of electrons from an acceptor to P700 results in the formation of ATP molecules.