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The pigments of the first part of photosynthesis, the light-dependent reactions, absorb energy from sunlight. A photon strikes the antenna pigments of photosystem II to initiate photosynthesis. The energy travels to the reaction center that contains chlorophyll a to the electron transport chain, which pumps hydrogen ions into the thylakoid ...
- 20.1: Light Absorption in Photosynthesis - An Overview
In radiative decay, a photon of lower energy is emitted...
- 20.1: Light Absorption in Photosynthesis - An Overview
In radiative decay, a photon of lower energy is emitted (after some energy has already been lost by vibrational transitions) in a process of either fluorescence or phosphorescence. In nonradiative decay, the energy of an excited electron can be transferred to another similar molecule (in this case other chlorophyll molecules) in a process that excites the electron in the second molecule to the ...
When a chlorophyll a molecule within the reaction center of PSII absorbs a photon, the electron in this molecule attains a higher energy level. Because this state of an electron is very unstable, the electron is transferred to another molecule creating a chain of redox reactions called an electron transport chain (ETC).
In the first part of photosynthesis, the light-dependent reaction, pigment molecules absorb energy from sunlight. The most common and abundant pigment is chlorophyll a. A photon strikes photosystem II to initiate photosynthesis. Energy travels through the electron transport chain, which pumps hydrogen ions into the thylakoid space.
- Charles Molnar, Jane Gair
- 2015
Photosystems exist in the membranes of thylakoids. A pigment molecule in the photosystem absorbs one photon, a quantity or “packet” of light energy, at a time. A photon of light energy travels until it reaches a molecule of chlorophyll. The photon causes an electron in the chlorophyll to become “excited.”
In photosynthesis, carotenoids function as photosynthetic pigments that are very efficient molecules for the disposal of excess energy. When a leaf is exposed to full sun, the light-dependent reactions are required to process an enormous amount of energy; if that energy is not handled properly, it can do significant damage.
People also ask
Which molecule absorbs energy in the first part of photosynthesis?
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How do light-dependent reactions begin in photosystem II?
The light absorption processes associated with photosynthesis take place in large protein complexes known as photosystems. The one known as Photosystem I contains a chlorophyll dimer with an absorption peak at 700 nm known as P700. Photosystem I makes use of an antenna complex to collect light energy for the second stage of non-cyclic electron ...
