Question

Explain the basic steps in the first half of photosynthesis (light-dependent reactions). Describe the movement of electrons and the importance of hydrogen ions in developing a proton gradient that allows for ATP production.

Answer 1

In the light-dependent reactions of photosynthesis, electrons become excited after photons strike the light-absorbing pigment chlorophyll. These excited electrons are then transferred from the chlorophyll to the electron transport chain. To replace the loss of electrons from the chlorophyll, water molecules present in chloroplasts are split in a process called photolysis. The separate components of water get recycled and used. The freed electrons replace those that supported the electron transport chain. The released hydrogen helps to develop a proton gradient in the thylakoid membranes. This gradient helps to fuel the production of ATP.

Step-by-step explanation:

Answer 2

Photosynthesis is the process by which plants make their own food in the presence of sunlight by utilizing carbon-dioxide and water and produces oxygen and energy.

The process of photosynthesis has two types of reactions: light-dependent reactions and light-independent reactions.

The light-dependent reactions occur in the thylakoid membranes of chloroplasts in which plants use light energy to form ATP and the reduced electron carrier NADPH.

In this reaction, photosystem II (P700) absorbs lights energy and passed it to reaction center. this energy is then is transferred to photosystem I (P680), that pump an electron to a high energy level. The high-energy electron then travel to an electron transport chain and releases energy. this released energy pump H+ ions into the thylakoid interior from the stroma and build a gradient H+ ions move through gradient and they pass through ATP synthase resulting in the formation of ATP.

The higher energy electron as moves into an electron transport chain, the electron is passed to NADP+ to form NADPH.