What is used to generate ATP molecules during photosynthesis

In plants, occur in the of the and use light energy to synthesize ATP and NADPH. The light-dependent reaction has two forms: cyclic and non-cyclic. In the non-cyclic reaction, the are captured in the light-harvesting of by and other (see diagram at right). When a chlorophyll molecule at the core of the photosystem II reaction center obtains sufficient excitation energy from the adjacent antenna pigments, an electron is transferred to the primary electron-acceptor molecule, Pheophytin, through a process called . These electrons are shuttled through an , the so called Z-scheme shown in the diagram, that initially functions to generate a across the membrane. An enzyme uses the chemiosmotic potential to make ATP during photophosphorylation, whereas is a product of the terminal reaction in the Z-scheme. The electron enters a chlorophyll molecule in . The electron is excited due to the light absorbed by the . A second electron carrier accepts the electron, which again is passed down lowering energies of . The energy created by the electron acceptors is used to move hydrogen ions across the thylakoid membrane into the lumen. The electron is used to reduce the co-enzyme NADP, which has functions in the light-independent reaction. The cyclic reaction is similar to that of the non-cyclic, but differs in the form that it generates only ATP, and no reduced NADP (NADPH) is created. The cyclic reaction takes place only at photosystem I. Once the electron is displaced from the photosystem, the electron is passed down the electron acceptor molecules and returns back to photosystem I, from where it was emitted, hence the name cyclic reaction.

Chemistry for Biologists: Photosynthesis - The Royal …

14/11/2006 · what are the reasons for enzymes in photosynthesis
Photo provided by
Flickr

Photosynthesis in Plants - Overview of Photosynthesis


Ferredoxin NADP Reductase (FNR) - transfers an electron from each of two ferredoxin molecules to a single molecule of the two electron carrier NADPH.
ATP Synthase - complex that uses the potential energy of flowing hydrogen ions to make ATP
Three Mobile Carriers that transports the electrons:
Plastiquinone Qb - transports the protons to the lumen of thylakoid discs, while the electrons continue through the electron transport chain into the cytochrome b6f protein complex.
Plastocyanin - functions as an electron transfer agent between cytochrome f of the cytochrome b6f complex from photosystem II and P700+ from photosystem I
Ferredoxin - accepts electrons produced from sunlight-excited chlorophyll and transfers them to the enzyme ferredoxin:NADP+ oxidoreductase

Light-dependent reaction
Light-independent reaction or Calvin Cycle

Light-dependent: converts light energy into chemical energy; produces ATP molecules to be used to fuel light-independent reaction, NADPH and Oxygen ( O2).

Light-independent: uses ATP produced to make simple sugars.

2 Phases of Photosynthesis
1.) A photon of light hits a chlorophyll molecule surrounding the Photosystem II complex; this creates resonance energy that transferred to neighboring chlorophyll molecules.

2.) When this energy reaches the reaction center embedded in Photosytem II, an electron is released.

One molecule of carbon dioxide is combined with one molecule of …

The NADPH is the main in chloroplasts, providing a source of energetic electrons to other reactions. Its production leaves chlorophyll with a deficit of electrons (oxidized), which must be obtained from some other reducing agent. The excited electrons lost from chlorophyll in are replaced from the electron transport chain by . However, since includes the first steps of the Z-scheme, an external source of electrons is required to reduce its oxidized chlorophyll a molecules. The source of electrons in green-plant and cyanobacterial photosynthesis is water. Two water molecules are oxidized by four successive charge-separation reactions by photosystem II to yield a molecule of diatomic and four ions; the electron yielded in each step is transferred to a redox-active residue that then reduces the photoxidized paired-chlorophyll a species called P680 that serves as the primary (light-driven) electron donor in the photosystem II reaction center. The oxidation of water is in photosystem II by a redox-active structure that contains four ions and a calcium ion; this binds two water molecules and stores the four oxidizing equivalents that are required to drive the water-oxidizing reaction. Photosystem II is the only known biological that carries out this oxidation of water. The hydrogen ions contribute to the transmembrane chemiosmotic potential that leads to ATP synthesis. Oxygen is a waste product of light-dependent reactions, but the majority of organisms on Earth use oxygen for , including photosynthetic organisms.

What is the name of the substance produced during the process of photosynthesis that serves as ..
Photo provided by
Flickr

Hopkins W.,Huner N.-Introduction to plant physiology …

Thus all life is supported by this process.
It also makes oxygen gas!!

Why is Photosynthesis important?

Plant leaves have many types of cells!

-site where light-dependent reactions occur
- site where light-independent reactions or the Calvin Cycle occur
6 molecules of carbon dioxide plus 6 molecules of water, produce 1 molecule of sugar and 6 molecules of oxygen.
What does the Equation mean:
Photosynthesis occurs in 2 stages.

Photosynthesis in plants occurs ..

ATP, NADPH and Molecular Oxygen are the final vital products of photosynthesis.

Occurs in the Thylakoid membranes
During the light reaction, there are two possible routes for electron flow:
A.

light-independent reactions of photosynthesis.

Photosynthesis converts these energy- depleted compounds (ADPand NADP+) back to the high energy forms (ATP and NADPH) and theenergy thus produced in this chemical form is utilized to drivethe chemical reactions necessary for synthesis of sugars andother carbon containing compounds (e.g., proteins, fats). Theproduction of high energy ATP and NADPH in plants occurs in whatis known as Light Phase Reactions (Z Scheme) (requiressunlight). The energy releasing reactions which converts themback to energy-depleted ADP and NADP is known as Dark PhaseReactions (Calvin Cycle) (does not require light) in whichthe synthesis of glucose and other carbohydrates occurs.