What are the steps of light-dependent reactions of photosynthesis?

Answer 1

As the name suggests, the light-dependant reaction depends on sunlight to carry out photosynthesis. Here, it traps solar energy and uses it to generate ATP and NADPH.

There are 4 steps to a light-dependant reaction.

First, photosystem II absorbs a photon, which excites an electron causing it to go to the electron acceptor, which means that photosystem II is now missing an electron. It regains the electron from water, producing oxygen. The resulting hydrogen ions remain in the thylakoid space and the oxygen is given off.

From the electron acceptor, the energized electrons are passed on to a series of electron carrying molecules, which forms an electron transport system. As electrons are transferred, the release energy is used to create a hydrogen proton gradient in the tylakoid.

At the same time, photosystem I absorbs light energy - and excited electrons leave the cell and are replaced by electrons coming in from Photosystem II

Electrons received by Photosystem I are used to reduced NADP+ to NADPH for used in light-independant reactions.

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Answer 2

Daniel Allen

The processes involved in light-dependent reactions of photosynthesis are as follows: 1. Light absorption by pigments such as chlorophyll in thylakoid membranes; 2. Electrons are excited and transferred through the electron transport chain; 3. Water molecules split into oxygen, protons, and electrons, releasing oxygen as a byproduct; 4. Chemiosmosis produces ATP; 5. Electrons from the electron transport chain reduce NADP+ to NADPH; and 6. Reoxidation of the electron transport chain resumes the electron flow.

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Answer 3

Sebastian Alvarado

The steps of light-dependent reactions in photosynthesis are as follows:

Absorption of Light: Light energy is absorbed by chlorophyll and other pigments in the thylakoid membranes of chloroplasts.
Water Splitting (Photolysis): The absorbed light energy is used to split water molecules into oxygen, protons (H⁺ ions), and electrons. This process occurs in the thylakoid lumen.
Electron Transport Chain (ETC): The high-energy electrons released from water move through an electron transport chain located in the thylakoid membrane. As electrons pass through the chain, their energy is used to pump protons from the stroma into the thylakoid lumen, creating a proton gradient.
ATP Synthesis: The proton gradient generated in the thylakoid lumen drives the ATP synthase enzyme to produce ATP from ADP and inorganic phosphate (Pi). This process is called photophosphorylation and occurs in the thylakoid membrane.
NADPH Formation: Another electron transport chain, known as the Photosystem I (PSI) electron transport chain, transfers electrons to NADP⁺ (nicotinamide adenine dinucleotide phosphate), reducing it to NADPH. This process involves the reduction of NADP⁺ and occurs in the stroma.

Overall, the light-dependent reactions of photosynthesis produce ATP and NADPH, which are energy carriers used in the light-independent reactions (Calvin cycle) to synthesize carbohydrates. Additionally, oxygen is released as a byproduct of water splitting.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.