Inside every living thing lives millions of cells Essays - Biology

Inside every living thing lives millions of cells that help our body perform chemical reactions and functions that help us survive. Inside this very cell holds different organs, called organelles, and different products of the cell. Each part of the cell has its own function, like a factory that manufactures products. Plant and animal cells are alike in several ways. Plant and animal cells are both eukaryotic cells, which means both cells include a nucleus. They have several features in common, such as the presence of a cell membrane, and cell organelles, like the mitochondria and endoplasmic reticulum. The cell membrane is a semi-permeable structure. It only allows some things in (such as glucose,) and only some things out. (cellular waste is an example.) In the center of the cell is the nucleus, the brains of the cell. The nucleus controls what every part of the cell does. For example, it may tell the mitochondria to break down more food because the cell does not have enough energy. Of course, plant and animal cells also have many different features. This so the cell is able to supply the needs of the organism. A plant needs sunlight in order to survive, but animals do not. Because the needs of animals and plants are different, their organelles vary also. In addition to the cell membrane, plant cells also have a thick cell wall. This is to help the plant keep its long, rectangular shape. When looking under a microscope, cell walls are a great way to distinguish plant cells from animal cells. Plants are also autotrophs; they produce energy from sunlight through the process of photosynthesis, for which they use cell organelles called chloroplasts. However, plant cells do contain mitochondria. While both plant and animal cells contain vacuoles, plant cells have one large central vacuole that can take up to 90% of cell volume. In plant cells, the function of vacuoles is to store water and maintain turgidity of the cell. Animal cells, on the other hand, have one or more small vacuoles. Vacuoles in animal cells store water, ions and waste. They also do not have chloroplasts. In animal cells, energy is produced from a simple sugar called glucose, via the process ofcellular respiration. Cellular respiration occurs in mitochondria on animal cells, which are structurally somewhat analogous to chloroplasts, and also perform the function of producing energy. Lysosomes are membrane-enclosed organelles that contain an array ofenzymescapable of breaking down all types of biological polymersproteins, nucleic acids, carbohydrates, andlipids. They can only be found in animal cells. Lysosomes function as the digestive system of the cell, serving both to degrade material taken up from outside the cell and to digest obsolete components of the cell itself. In their simplest form, lysosomes are visualized as dense spherical vacuoles, but they can display considerable variation in size and shape as a result of differen ces in the materials that have been taken up for digestion.