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Using the energy carriers formed in the first steps of photosynthesis, the light-independent reactions, or the Calvin cycle, take in CO 2 from the environment. An enzyme, RuBisCO, catalyzes a reaction with CO 2 and another molecule, RuBP.
- The Light-Dependent Reactions
The light-dependent reactions release oxygen as a byproduct...
- Photosynthesis in Prokaryotes
The two parts of photosynthesis—the light-dependent...
- 2.21: Light Reactions of Photosynthesis
Light is the source of energy for photosynthesis, and the...
- 25: Light and Photosynthesis
Photosynthesis takes place in two sequential stages: the...
- The Light-Dependent Reactions
Light is the source of energy for photosynthesis, and the first set of reactions which begin the process requires light – thus the name, light reactions, or light-dependent reactions. When light strikes chlorophyll (or an accessory pigment) within the chloroplast, it energizes electrons within that 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.
Jan 18, 2022 · Light-dependent reaction is the series of biochemical reactions in photosynthesis requiring light energy that is captured by light-absorbing pigments (such as chlorophyll) to be converted into chemical energy (ATP and NADPH).
Photosynthesis takes place in two sequential stages: the light-dependent reactions and the light independent-reactions (Calvin cycle). In the light-dependent reactions , energy from sunlight is absorbed by chlorophyll and that energy is converted into stored chemical energy.
The reactions that make up the process of photosynthesis can be divided into light-dependent reactions, which take place in the thylakoids, and light-independent reactions (also known as dark reactions or the Calvin cycle), which take place in the stroma.
Light reaction is the first stage of photosynthesis process in which solar energy is converted into chemical energy in the form of ATP and NADPH. The protein complexes and the pigment molecules help in the production of NADPH and ATP.
