Every living thing on Earth has cells. Cells are made up of small pieces called proteins and organelles. The larger pieces are tissues and systems. Cells hold biological equipment that keeps them alive. A cells job is to organize. Each cell has a different function. Organisms grow and survive better when cells are present. If people were only made up of one cell they could only grow to one size. You also would not have a nervous system or muscles. A person’s body is made up of trillions of cells. Animal-like cells differ from plant-like cells. An animal-like cell could be a tiny microorganism or a nerve cell. Plant cells differ because they have protective structures with walls. Each organism has its own unique cell. People have hundreds of cells that are used to do different things in our bodies. All cells are surrounded by a membrane. Animals, people and insects have a nervous system. Some of the systems are more complex than others. A person’s nervous system consists of two parts: The central and the peripheral. The central nervous system is your spinal cord and your brain. The peripheral system makes up your organs, body and muscles. The reason people can react or take action is directly related to our nervous system. How people and animals smell, see and taste are related to our nervous system. Some of the things our nervous system does we don’t even think about. All of the systems in our bodies take direction from our nervous system. If we are eating our body starts to digest our food without us doing anything. That has to do with our nervous system and we have no idea it is even going on. Muscles in our body are made up of three kinds of tissue: Smooth, cardiac and voluntary. Each type of tissue has a different part of the body it is in. The smooth tissue is in our organs, the cardiac is in our heart, and the voluntary is the muscle that helps us move. We have little or no control over most of the muscles in our entire body. Muscles interact with our nervous system. If a cell doesn’t have a job it is not needed. They all have a purpose and that purpose is to survive. If any cell is missing a piece it would die. All the pieces of a cell are called organelles. Complex molecules make up organelles and that is what keeps cells alive. If a cell is growing it needs more organelles than a smaller cell. Mitochondria help cells process food into energy. A larger cell would need more mitochondria than a smaller cell. Cells that are more advanced do not survive well on their own. Cells that are not advanced could live on their own.
Animal and plant cells differ. If you are not an animal or a microbe you would be a plant. Plants have a classification system that is similar to that of an animal. All plants have photosynthesis in common. This process is how plants take energy and create sugar. Some plants do not use this process. The species of plants that are parasites do not use this process. All plants have cell walls. When plants use photosynthesis they store energy to be used later. Plants release energy using respiration and they store it using photosynthesis and to do this they need the sun. Plants are used in the study of genetics. A scientist actually studied plants to get some ideas of how traits are passed from one generation to the next. Because we use plants as food scientists are always trying to develop plants that are resistant to insects and disease. They have also developed ways to help plants grow faster so you can produce more food. Humans and animals need plants. Plants have made it possible for humans to be civilized. Humans use to hunt for food and were not very good at it. Once someone decided to plant food that people liked to eat they were able to stay in one place permanently. Then that idea took off and people started to plant large lots of food to eat that could support lots and lots of people. Farming has grown into a multi-billion dollar industry. Over the years crops have been made to grow bigger and bigger. I am not talking about the size of land the crops are grown on but the size of the item itself. Apples for one have been getting larger and larger over time. People have learned how to cross two plants to get larger fruit. Farmers are also working with the crops to produce that will not be hurt by bugs or disease. Plants would never have crossed in the wild. Plants have also been used for medicine. Some plants have been healing people for hundreds of years. Some plants will be discovered to have healing powers in the future. Scientists have and will continue to study the cell makeup of plants and animals. With this research we can only hope that cures to the most deadly disease will be found and people can be cured.