The plant cell
True or false? Only plant life depends on photosynthesis.
What’s the difference between animals and plants? Yes, the question might seem weird. It’s easy, right, to see that plants stand still, firmly rooted, whereas animals jump, fly, and swim about. But what about this? This organism consists of one single cell, floating around in the water.
It neither swims, like an animal. Nor has it green leaves, like a plant. Is it an animal, or a plant, or something totally different? Actually, it is a plant. But how can we know that for certain?
What is special about plants? Partly, the explanation lies in the way the cell is structured. Plant and animal cells have a lot in common, like the nucleus and other organelles. But there are also important differences. Let’s have a look at some of those.
In an animal cell, it’s the cell membrane that forms the outer layer. ...but watch, a plant cell has an extra layer around the membrane. This is the cell wall. The cell wall is strong and often gives a somewhat angular shape. Plants don’t have skeletons to give stability and structure. Instead, it’s the stability from the hard cell walls that enables the plants to stand upright and grow tall.
In the plant cell, there is also a big clear bag, filled with water. It’s called a vacuole. It’s thanks to the water in the vacuole that the pressure inside a cell is maintained. When the plant dries out, the pressure in the cells decreases. The cells lose their stability and the plant withers.
But when it rains again, the vacuole fills with water, and the plant regains its stability. In seeds, which are dry and don’t contain a lot of water, the vacuole instead is a store room for the proteins necessary for the plant to set root and grow. Most plant cells have a single vacuole that takes up much of the space in the cell. Many plant cells are green. They get their colour from small green granules containing chlorophyll.
Chlorophyll uses the light of the sun and creates its own nutrition in a process called photosynthesis. It is one of the most important chemical reactions in the world. It is the foundation for the lives of plants and animals on Earth. In photosynthesis, water and carbon dioxide co-operate with the energy from the sun. This creates glucose, that the plant needs.
Also, oxygen is created, which is something all plants and animals on earth need. Almost all the oxygen that you breathe in right now was released within a plant cell, in the tiny granules containing chlorophyll. The granules are called chloroplasts. So, if there were no plants nor plant cells, we wouldn’t have any oxygen to breathe? No.
Almost all life on earth relies on photosynthesis. And it happens in the plant cell. Three important facts about the plant cell: [1] A plant cell has a cell wall that gives stability to the cell and the plant. [2]A plant cell has a large vacuole. It’s mostly filled with water and also contributes to the stability of the cell. [3]In the plant cell you find green chloroplasts, filled with chlorophyll. Here, photosynthesis takes place, which most of life on Earth depends on.