What Are the Beginning & End Products of Photosynthesis?

Water and Carbon Dioxide

• The roots of a plant draw water by means of the xylem, highly specialized cells. Gas can enter and exit the leaves through stomata or tiny openings. The surface of a leaf is too waxy for carbon dioxide to pass through, but it can enter via the stomata. Each stoma has two guard cells beside it. Oxygen created during photosynthesis exits the leaf via the opened stomata. The exchange of gasses into and out of the leaf results in a loss of water from the leaf, and the plant must take in more moisture to avoid dehydration.

Leaf Structure

• Photosynthesis occurs in the leaves of plants. The epidermis, the outer layer of the leaf, protects the leaf. Since neither the lower or upper epidermal cells of the leaf contain chloroplasts, no photosynthesis occurs there. Rather, it is in the mesophyll that is rich in chloroplasts where the reaction takes place. Chloroplasts contain chlorophyll, a green pigment needed in order for photosynthesis to occur. The veins of the leaf are also known as vascular bundles. They transport nutrients and water to where it is needed.

Photosynthesis

• Photosynthesis can be divided into two parts. The first part is the light reaction which takes place in the thylakoid membrane. It involves the conversion of light energy to chemical energy. This part of the reaction has to take place in the daytime when it is light. Chlorophyll and a number of pigments are part of this light reaction. The energy gathered during the light reaction forms ATP (adenosine triphosphate) which is a chemical compound that cells use to store energy. The second part of photosynthesis is called the dark reaction. It occurs inside the chloroplast where carbon dioxide is converted to sugar. An essential part of the dark reaction is the Clavin cycle, which uses energy from ATP created in the light reaction.

Oxygen and Sugar

• The chemical reaction that takes place during photosynthesis results in the production of sugar and oxygen. Oxygen is vital to our survival; we need it in order to breathe. The equation that describes photosynthesis is written as: 6H2O + 6CO2 C6H12O6 + 6O2. Essentially, six water molecules join with six carbon dioxide molecules to create one molecule of sugar and release six molecules of oxygen.