What are the 4 steps of light reactions?
- 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 ...
- ATP synthesis.
- Light absorption in PSI.
- NADPH formation.
What happens during light reactions?
What are the major events that occur during the light reactions?
- B oxidation of water, reduction of NADP + , formation of ATP.
- C oxidation of water, recuction of NADP + , hydrolysis of ATP.
- D fixation of carbon dioxide, release of oxygen, synthesis of glucose.
- E release of oxygen, fixation of carbon dioxide, hydrolysis of ATP.
What are the steps of light dependent reactions in photosynthesis?
What are the 7 steps of light-dependent reactions?
- (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 equation for light reaction?
What is the equation for light reaction? During the light reactions, water is oxidized, electrons are transferred from water to NADP +, and ATP is synthesized. The three components of the light reaction can be summarized with equations: 2 H 2O + 2 NADP + + nADP + nP i + hv O 2 + 2 NADPH + 2 H + + nATP.
What do light reactions require?
The pigment, chlorophyll, which is required for the process is present on the membrane of these thylakoids and this is where the light reaction occurs. The main purpose of the light reaction is to generate organic energy molecules such as ATP and NADPH which are needed for the subsequent dark reaction.
Where does the light dependent reaction occur?
Light Reaction. (Image Source: actforlibraries.com) The light reaction of light dependent reaction occurs in the chloroplast of the mesophyll cells of the leaves. The chloroplasts are double-membraned cell organelles that are comprised of stacked disc-like structures known as thylakoids.
What are the two steps of photosynthesis?
Co2, water, chlorophyll, and sunlight are four important requirements for this process. Photosynthesis occurs in two steps: Light reaction and Dark Reaction.
What happens when light falls on a plant?
When the light falls on the plant, the chlorophyll pigment absorbs this light and electrons in it gets excited. This process occurs in a complex protein system which is collectively called as a photosystem. There are two closely linked photosystems known as PSI and PSII.
How many electrons does water release from the PSII?
The chlorophyll pigments which are excited give up their electrons and to compensate for the loss of electrons, water is split to release four H+ ions and four electrons and O2. The electrons that are lost from the PSII enter into an electron transfer chain or ETC.
What are the factors that influence photosynthesis?
For any plant performing photosynthesis, four factors influence this process. CO2, water, light, and chlorophyll are the raw materials for photosynthesis. But, in case of light dependent reaction or light reaction of photosynthesis, it is most influenced by presence or absence of light.
What ions are in the lumen of the ATP synthetase?
The hydrogen ions building up inside the lumen creates a positive gradient and in the presence of the enzyme ATP synthetase, these H+ ions combine with the ADP in the nearby region to form ATP.
Where do electrons combine with NADP+?
The electrons finally reach the reaction centre where they combine with NADP+ and reduce it to NADPH
Emerson Red Drop and Enhancement Effect
Photosystems Or Pigment Systems
- 1. In green plants, the photosynthetic units occur in the form of two distinct photosystems (or pigment systems), PS-I and PS-II (named in the chronology of discovery). 2. The PS-I, along with some electron carriers, is located on both the non-appressed part of grana and stroma thylakoid. Conversely, PS-II, along with the electron carriers, are located on the appressed part of the gran…
Summary
- Thus, light reaction of photosynthesis is defined as a series of chemical reactions that require light energy captured by the pigment present in the leaves (such as chlorophyll) to get converted into chemical energy in the form of ATP and NADPH. It is one of the most important phases of the photosynthetic reactions as photosynthesis demands a huge requirement of light energy and th…
FAQs
- Q.1. What is the major function of light reaction? Ans: The major function of light reaction is to provide an energy source to the antenna pigment molecules so that they get excited, and due to the excitation, a series of electron transport chains will result in the formation of ATP. Q.2. What is the light and dark reaction of photosynthesis? Ans:The light reaction is the preparatory stage of t…