Where is energy stored during photosynthesis?

The energy is stored during photosynthesis in chlorophyll.

Chlorophyll is the photosynthetic pigment that gives the green color present in plants and is the molecule responsible for the transformation of the sun's energy in the photosynthesis process.

Chlorophyll absorbs photons of light with the consequent excitation of an electron, that excited electron gives up its energy, returning to the normal state, to some auxiliary pigment (sometimes other chlorophylls), where the phenomenon is repeated.

In the end, the excited electron facilitates the reduction of a molecule, thus completing the conversion of a small amount of light energy into chemical energy, one of the essential functions of photosynthesis.

The light energy captured by chlorophyll is converted into adenosine triphosphate (ATP) and reducing molecules (NADPH) through a series of chemical reactions that take place in grana.

Therefore, we can conclude that the energy is stored during photosynthesis in chlorophyll.

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Photosynthesis can be described as a process by which  plants make sugar and oxygen from water and carbon dioxide in the presence of sunlight. The light energy from the Sun is stored in the chemical energy of the sugar or glucose produced during the process of photosynthesis. This energy is stored in the chloroplast and passed on to cells to carry out different functions. Usually, the energy is stored in the form of starch.

a sperm cell fertilizes an egg cell.