What is Photosynthesis?

 What is Photosynthesis?

 

What we will Learn: What is Photosynthesis? Process of Photosynthesis: How do Plants make food? Do you have any idea about how plants make their own food and produce oxygen? Let us learn about the complete process. Plants take in carbon dioxide from air and water from the soil; put them together in the presence of sunlight and chlorophyll to produce sugar (glucose) and oxygen. The process is called photosynthesis. The sugar produced is used by the plant for its life processes such as growing and reproducing while the excess is converted mainly to starch and stored in various plant parts which may be used as food by animals and humans. Photosynthesis is a process that differentiates plants from the rest of the living organisms. It is only because of this process that we call plants an autotroph (organisms that could synthesize their own food) and the rest as heterotrophs (those that cannot synthesize their own food). Plants are important for all living organisms because they give us food to eat and oxygen to breathe. Plants inhale carbon dioxide and exhale oxygen while we human inhale oxygen and exhale carbon dioxide. Photosynthesis is a complex reaction. In a lot of ways, it's similar to the way our body breaks down food into fuel that it can store. Essentially, using energy from the sun, a plant can transform carbon dioxide and water into glucose and oxygen. The process by which plants make food is called "photosynthesis". The word "photosynthesis" is made up of two words: "photo" = light "synthesis" = putting together The Process of Photosynthesis Photosynthesis occurs mainly within the leaves. Photosynthesis requires carbon dioxide, water, and sunlight. (a) Plants get water from soil through roots. (b) Plants obtain carbon dioxide from air through tiny pores in leaves called stomata. (c) Plants absorb sunlight through chlorophyll, a green pigment located in plant cell structures. (1) Water and minerals from the soil are absorbed through the root and transported to the leaves through vessel known as xylem vessels. Xylem is similar to the straw that we use to suck liquids. These vessels are found right throughout the plants from the leaves, stem, and are said to connect every part of the plant. Xylem is involved in the transport of both vital nutrients and water from the soil to all parts of the plant. (2) Leaves of the plant have tiny pores called stomata. Each stoma (singular) is bounded by guard cells. The guard cells regulate the opening and closing of the stoma. When there is ample carbon dioxide in the atmosphere and abundant light, the stomata open to bring in the carbon dioxide required for the photosynthesis process. Hence the plant's stomata allow carbon dioxide to enter the plant's leaves to be used in the photosynthesis. The plant also requires a means to release the oxygen that is a byproduct of the photosynthesis process. The stomata also provide a means for the elimination of oxygen from the plant after photosynthesis has taken place. (3) Plants contain cells known as mesophyll that contain specialized cell structures called chloroplast. The chloroplasts contain chlorophyll that is responsible for the green coloration of the plants. One plant leaf is composed of thousands of cells, and each cell contains 40 to 50 chloroplasts. The chloroplast, an oval-shaped structure, is divided by membranes into numerous disk-shaped compartments. These disk like compartments, called thylakoids are arranged vertically in the chloroplast like a stack of plates. A stack of thylakoids is called a granum (plural, grana). The grana lie suspended in a fluid known as stroma. Embedded in the membranes of the thylakoids are hundreds of molecules of chlorophyll, a light-trapping pigment required for photosynthesis. (4) Once the carbon-dioxide and water reach the chloroplasts in the presence of sunlight, the process of photosynthesis begins. Sunlight is absorbed by chlorophyll, a green pigment located in plant cell structures called chloroplasts . The following is the reaction that happens inside the chloroplast of the plant. Products of photosynthesis: Glucose and Oxygen (a) Glucose, a carbohydrate processed during photosynthesis, is mostly used by plants as an energy source to build leaves, flowers, fruits, and seeds. The unused glucose produced during photosynthesis would be stored as starch in leaves and roots. This unused glucose would be used by the plants when there is no photosynthesis. (b) Oxygen that is liberated as a by-product passes out through the stomatal opening. This oxygen would be utilized by the humans for respiration.