Energy is what keeps our bodies growing and our brains working. People and animals get their energy from the food we eat, like fruits and vegetables.
But where do the fruits and vegetables get their energy? Unlike people who have to eat energy, plants make their own. They do it through a process called photosynthesis. Photosynthesis is a chemical process that takes place at the cellular level inside leaves. It requires three important ingredients in order to work. Carbon dioxide CO2 is a gas in the air all around us. This is great news for plants, who need it to survive.
The rays of the sun are what bring it all together. Photosynthesis occurs in two stages commonly known as Light dependent Reactions and the Calvin Cycle. Light dependent reactions occur in the thylakoid membrane of the chloroplasts and take place only when light is available.
During these reactions light energy is converted to chemical energy. The Calvin Cycle reactions occur in the stroma of the chloroplasts. More details about the formation of sugars can be found under the Process of Photosynthesis in Plants. You already know that plants need carbon dioxide , water and sunlight to make their food.
You also know that the food they make is called glucose. In addition to glucose, plants also produce oxygen. This information can be written in a word equation as shown below. The equation below is the same as the one above but it shows the chemical formula for carbon dioxide, water, glucose and oxygen.
Now back to the definition… Earlier you learned that photosynthesis is the process by which plants make their own food. Now that we know what plants need to make food, we can add that information as shown below. Photosynthesis is the process by which plants make their own food using carbon dioxide, water and sunlight. Some of the glucose that plants produce during photosynthesis is stored in fruits and roots. This is why we are able to eat carrots, potatoes, apples, water melons and all the others.
The water, which is in the soil, travels through the roots, up the stem and into the leaves…kind of like a big straw. But plants are very clever and have a specialized structure called stomata which will not allow carbon dioxide to pass through its protective waxy layer covering the leaf cuticle. Plants do the same thing, except when they take a deep breath, they breathe in carbon dioxide and when they let it out, it is oxygen.
The stoma are so small you have to have a microscope to see them, but they are big enough to breathe in the carbon dioxide a plant needs to make its food. Plants take in carbon dioxide through their leaves at the same time they are soaking up energy from the sun and taking a drink of water.
Once the leaves of a plant have collected enough carbon dioxide, water and sun-energy, they are ready to make food for the entire plant. When the carbon dioxide, water, and energy from the sun are combined, the sun turns the water and carbon dioxide into glucose sugar. While the process can be complicated, it can be simply written with the following word equation:. Photosynthesis happens in the leaves of the plants where chloroplasts live in cells.
There are two stages in photosynthesis. The first stage needs light and the second stage does not. Before you can understand the process of photosynthesis, you have to understand more about chloroplasts. Just like humans, plants are made up of thousands of cells. Unlike animal cells, plants have a special structure called chloroplasts where photosynthesis happens.
Chloroplasts are tiny oval-shaped blobs found inside plant cells. Sometimes plant cells only have a few chloroplasts while others take up the whole space inside a cell. Chloroplasts have many layers. The outer layer is smooth while the inside of the chloroplast contains several important pieces. Inside the chloroplast is a collection of sacks full of chlorophyll called thylakoids that float in a fluid called stroma. Thylakoids look like stacks of pancakes. Chlorophyll gives plants their green color and helps plants absorb energy from the sunlight.
The first stage of photosynthesis is called the light dependent reactions stage.
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