Search results
Sep 21, 2021 · The light-dependent reactions begin in a grouping of pigment molecules and proteins called a photosystem. 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.
- The Calvin Cycle
The Calvin cycle is the term used for the reactions of...
- Overview of Photosynthesis
The light-dependent reactions release oxygen from the...
- The Calvin Cycle
The visible light portion of the electromagnetic spectrum is perceived by the human eye as a rainbow of colors, with violet and blue having shorter wavelengths and, therefore, higher energy. At the other end of the spectrum toward red, the wavelengths are longer and have lower energy.
- Charles Molnar, Jane Gair
- 2015
In the light-dependent reactions, energy absorbed by sunlight is stored by two types of energy-carrier molecules: ATP and NADPH. The energy that these molecules carry is stored in a bond that holds a single atom to the molecule. For ATP, it is a phosphate atom, and for NADPH, it is a hydrogen atom.
In the light-dependent reactions, energy absorbed by sunlight is stored by two types of energy-carrier molecules: ATP and NADPH. The energy that these molecules carry is stored in a bond that holds a single atom or group of atoms to the molecule.
- Step 1: Excitation of Photosystems with Light Energy and Photolysis of Water
- Step 2: Generation of ATP by Electron Transport Chain
- Step 3: Formation of NADPH
- Alternative Pathway
- Chemical Equation
- Fate of The Products
The function of the light-dependent reaction is to convert light energy into chemical energy within a multi-protein complex called the photosystem, found in the thylakoid membranes. There are two types of photosystems found in most plants: photosystem I (PSI) and photosystem II (PSII). Each photosystem is made of two components: 1) antenna complex ...
The electrons released from photosystem II enter a chain of proteins known as electron transport chain (ETC). They move from PSII to a small lipid-soluble molecule, plastoquinone (Pq), and then to a protein complex called cytochrome b6f. The electrons are finally transferred to a copper-containing protein called plastocyanin (Pc) before being accep...
This stage is the final step of the light-dependent reaction during which high energy electrons released from PSI travel a short second leg of the electron transport chain. Here, the electrons are first transferred to an iron-containing protein called ferredoxin (Fd) and then to a reducing agent, NADP, to form NADPH. This type of electron transport...
Sometimes plants follow an alternative path of electron transport called cyclic photophosphorylation. This term is named so because electrons released from PSI move along a circular path before returning to the same photosystem. Cyclic photophosphorylation does not involve PSII and produces only the ATP, stopping the production of NADPH.
2H2O + 2NADP+ + 3ADP + 3Pi → O2+ 2NADPH + 3ATP Reactants 1. H2O 2. NADP 3. ADP + Pi End Products 1. O2 2. NADPH 3. ATP
The energy-carrier molecules, ATP, and NADPH produced in the light reaction are used in the second phase of photosynthesis or the Calvin cycle to assemble sugar molecules.
Absorption of Light. Light energy initiates the process of photosynthesis when pigments absorb specific wavelengths of visible light. Organic pigments, whether in the human retina or the chloroplast thylakoid, have a narrow range of energy levels that they can absorb.
People also ask
What is the purpose of light-dependent reactions?
Where do light-dependent reactions begin?
How do light-dependent reactions convert solar energy into chemical energy?
What happens to light energy after a chemical reaction?
Why do light-dependent reactions release oxygen as a byproduct?
Is light a form of energy?
In the light-dependent reactions, energy absorbed by sunlight is stored by two types of energy-carrier molecules: ATP and NADPH. The energy that these molecules carry is stored in a bond that holds a single atom to the molecule. For ATP, it is a phosphate atom, and for NADPH, it is a hydrogen atom.
