A city is made up of many buildings. A city needs a library, fire station, school, and apartment buildings in order to work! There needs to be a place to find information, a place for people who help put out fires, a place to learn, and places for all these people to live. Inside each building there are many different rooms, with many things inside the rooms. There may be furniture, books, rugs, and other items. All parts are important to the building, and each building is important to the city.
Some cities have special buildings. Seattle has a Space Needle.
Your body is like a city. You're made up of very tiny parts. They are so small you can't see them with your eyes. They have all the information your body needs to grow and live. Each one is important. These tiny parts are your cells.
That's the way it is with all living things: dogs, cats, monkeys, fish, ants, bees, spiders, trees, flowers, or moss. They are made up of cells, but not all cells are the same. Plant cells and animal cells are different. The plants may be tall like trees or small like grass, but their cells all have certain parts. If a cell has these parts, you know it is a plant cell and not an animal cell.
Not only do trees have to stand up all day. They have to stand up all night too.
Each plant cell is surrounded by a strong wall that's not found in an animal cell. This is like the walls of a building. They support the building and keep it standing up straight. Everything inside is safe from wind, rain, snow, heat, and cold. This building is not completely sealed, though. There are windows and doors to let some things go in and out.
In plant cells, those walls are made of sugars, and they are very strong. Plants have no bones like you, so the walls help the plant stand up. Cell walls
in plant cells protect the inside of the cell, help the plant stand upright, and even have holes that let food, waste, or water in and out.
Have you ever seen a plant that droops? Its stem and leaves are very limp. Too much water has gone out through the cell walls. You can fix this by watering the plant. The added water will go through the cell walls into the cell. Soon, the plant will look fresh and springy again.
Water, I need water.
There's a special place inside the plant cell that stores the water for the plant. If you think of the cell as a building again, this place could be the kitchen. It stores water and food. It even keeps waste there, just like the trash can in a kitchen, to help keep everything clean. In this building, the kitchen is big, at least one-third the size of the whole place.
The cells of a young plant may have a few spots where they can store things. Adult plants have just one for each cell. It keeps the important things inside, like food and water. It even keeps waste inside so it doesn't spread through the whole plant and harm it. After a while the waste breaks up into small pieces that cannot hurt the plant, so it leaves the cell.
The large vacuole
is where plant cells stores water, waste, and food. The vacuole can take up more than one-third of the whole cell, but there are other important parts as well. Think about the cell as a building again. Each one needs a place to make power so it will be warm in the winter and cool in the summer. People used to cut down trees and store wood to use to heat their houses, but this doesn't happen inside most buildings anymore. Instead, there's a power plant in the city that makes electricity and sends it out with wires to the buildings to give them the energy they need.
Inside a plant cell there are certain parts that make the power the plant needs. Chloroplasts
take sunlight, water, and a certain gas from the air and turn them into food for the plant. Inside these parts, the energy from the sun is changed into energy the plant can use. The plant uses this energy to do all its work. Only plant cells have these parts. Animals can't make their own food inside their bodies.
Sunlight powers plant cells.
Cells of plants and animals are similar in many ways, but there are important differences. Plants have parts that protect them, help them stand up straight, store the things they need, and make their own food. Don't feel too bad that you can't make food inside your cells. Remember, plants have only one kind of food: Sugar. You have lots more choices: milk, cookies, ice cream, bread, ham, eggs, and apples, to name a few. What are your favorites?