How do excited electrons from photosystem II generate ATP?

How do excited electrons from photosystem II generate ATP?

Protons diffuse out of the thylakoid lumen through the enzyme, ATP synthase, producing ATP in the process. Once the electron reaches PSI, it joins its chlorophyll a special pair and re-excited by the absorption of light.

What happens to the excited electrons from chlorophyll?

To replace the electron in the chlorophyll, a molecule of water is split. The energy “excites” one of its electrons enough to leave the molecule and be transferred to a nearby primary electron acceptor. A molecule of water splits to release an electron, which is needed to replace the one donated.

How does photosynthesis produce ATP?

The ATP is produced during the light reaction of photosynthesis by photophosphorylation. ATPs are produced towards the stromal side of the thylakoid membrane. In the formation of one glucose molecule, 18 ATP and 12 NADPH molecules are utilised in the six turns of the Calvin cycle. …

How is ATP produced from the electron transport chain in the light reactions?

They escape the thylakoid through a membrane protein called ATP synthase. By moving through the protein they give it power, like water moving through a dam. When hydrogen ions move through the protein and down the electron transport chain, ATP is created.

What is the role of excited electrons in photosynthesis?

Sunlight is absorbed by photosynthetic pigments, the most abundant of which in plants are the chlorophylls. Absorption of light excites an electron to a higher energy state, thus converting the energy of sunlight to potential chemical energy.

How does cyclic electron flow produce ATP?

In cyclic electron flow (CEF), electrons are recycled around photosystem I. As a result, a transthylakoid proton gradient (ΔpH) is generated, leading to the production of ATP without concomitant production of NADPH, thus increasing the ATP/NADPH ratio within the chloroplast.

What happens during the electron transport chain of the light reactions?

The electron transport chain moves protons across the thylakoid membrane into the lumen. At the same time, splitting of water adds protons to the lumen, and reduction of NADPH removes protons from the stroma. The net result is a low pH in the thylakoid lumen, and a high pH in the stroma.

What happens during the electron transport chain of the light reactions quizlet?

What happens during the electron transport chain of the light reactions? The electrons get increasingly excited as they move up the chain. The electrons interact with oxygen to move up the chain. The electrons release their energy, which is captured by ATP and NADPH.

How are electrons excited during photosynthesis?

Absorption of light excites an electron to a higher energy state, thus converting the energy of sunlight to potential chemical energy. The photosynthetic pigments are organized into photocenters in the thylakoid membrane, each of which contains hundreds of pigment molecules (Figure 10.20).

How is ATP produced in the mitochondrion in photosynthesis?

This same protein generated ATP from ADP in the mitochondrion. The energy generated by the hydrogen ion stream allows ATP synthase to attach a third phosphate to ADP, which forms a molecule of ATP in a process called photophosphorylation.

Where does the excited electron go in photosynthesis?

From photosystem II, the excited electron travels along a series of proteins. This electron transport system uses the energy from the electron to pump hydrogen ions into the interior of the thylakoid. A pigment molecule in photosystem I accepts the electron.

How does light get to the pigments in photosystem?

Pigments in the light-harvesting complex pass light energy to two special chlorophyll a molecules in the reaction center. The light excites an electron from the chlorophyll a pair, which passes to the primary electron acceptor. The excited electron must then be replaced.

What kind of energy can organic pigments absorb?

Organic pigments, whether in the human retina or the chloroplast thylakoid, have a narrow range of energy levels that they can absorb. Energy levels lower than those represented by red light are insufficient to raise an orbital electron to a excited (quantum) state.