The Three Main Parts of Cell Theory — Reading Comprehension

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This educational passage, 'The Three Main Parts of Cell Theory,' is designed for 6th-grade students to understand a foundational concept in biology. It delves into the essential principles of cell theory, explaining how all living things are composed of cells, that cells are the basic unit of life, and that new cells arise from existing cells. Aligned with NGSS standard MS-LS1-1, 'Conduct an investigation to provide evidence that living things are made of cells; either one cell or many different numbers and types of cells,' this passage provides a clear and accessible introduction to cell biology. Students will learn key vocabulary related to cells and organisms. The content is audio integrated to enhance accessibility and learning for diverse student needs, making complex scientific ideas understandable and engaging.

CONTENT PREVIEW

Imagine looking at a tiny piece of an onion skin under a microscope. You'd see many small, box-like structures. These are cells! They are the fundamental building blocks of all living things, from a towering tree to a microscopic bacterium, and even you! Scientists have discovered some incredible facts about cells over hundreds of years, which led to something called the Cell Theory. This theory has three main parts that help us understand life on Earth.

The first part of Cell Theory states: All living things are made of cells. This means that every organism you can think of, whether it's a small ant or a giant whale, is made up of one or more cells. Some organisms, like bacteria, are unicellular, meaning they consist of just one cell. Others, like humans, are multicellular, meaning they are made of countless cells working together. These cells perform different jobs to keep the organism alive and functioning.

The second part of Cell Theory tells us: Cells are the basic unit of structure and function in living things. Think of it like this: if an organism were a house, cells would be like the individual bricks, rooms, and even the electrical wiring. Each cell has its own specific job. For example, in your body, nerve cells send messages, muscle cells help you move, and skin cells protect you. They are the smallest units that can carry out all the processes necessary for life, like taking in nutrients, growing, and getting rid of waste.

Finally, the third part of Cell Theory explains: All new cells are produced from existing cells. Cells don't just appear out of nowhere! They divide to create new cells. This process is essential for growth, repairing damaged tissues, and even for reproduction in many organisms. For instance, when you get a cut, your body's existing skin cells divide to make new ones and heal the wound. This continuous process ensures that life can continue and thrive.

The Cell Theory is a cornerstone of biology, helping us understand how all living things are connected and how life continues on our planet. It highlights the amazing microscopic world that makes up everything around us, including ourselves!

Interesting Fact: The first person to observe and name cells was Robert Hooke in 1665, when he looked at a piece of cork through a microscope.

What did Robert Hooke name?

CellsOrganismsThe Cell TheoryBiology

What is the third part of Cell Theory?

Cells come from existing cellsCells are the basic unitAll living things have cellsCells are always unicellular

Which of these is TRUE?

All organisms are multicellular.True

Which word means having one cell?

UnicellularMulticellularOrganismBiology

Why is cell division important?

For growth and repairOnly for reproductionTo make organisms unicellularTo remove all cells

How do nerve cells help the body?