53 L6-Cells and Microbes

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Oxford Read and Discover level 6 Cells And Microbes by Louise & Richard Spilsbury

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introduction What are the smallest living things on Earth? The answer is cells. Some of the biggest living things, like whales, people, or trees, are made of millions of tiny cells! Microbes are living things that usually have just one cell. How do we know about cells? What types of cell do you know? How many cells are there in your body? Discover! Now read and discover more about amazing cells and microbes!

Chapter 1 Discovering Cells Most cells are too small to see, so how do people know that living things are made of cells? No one knew about cells until microscopes were invented. Microscopes magnify tiny things, like cells, to make them look bigger, so that people can see them. Learning About Cells In 1665 a British scientist called Robert Hooke made one of the first microscopes. He used it to look at a thin piece of tree bark called cork. He saw that the cork was made of lots of tiny pieces. These were the cork cells. Today, microscopes can magnify things a million times! Discover! When Robert Hooke saw the pieces inside the cork, he called them 'cells' because they looked like little rooms called cells.

Living Cells If cells are so small, how do we know if they are living or not? We know a cell is living because it does what other living things do. A cell can get energy from its food and a cell can move. A cell can grow so it can get bigger. A cell can reproduce it can make more cells. Most living things are made of many cells. The simplest living things are made of just one cell. We call them microbes because we can only see them through a microscope. An amoeba is one of the biggest types of microbe, but it's so small that 50 amoebas together are only as big as one grain of rice!