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Discover the fascinating world of cells, from their microscopic details to the development of cell theory by key figures like Robert Hooke and Anton van Leeuwenhoek. Learn about the basic units of life and the significance of cells in all living organisms. Explore the differences between unicellular and multicellular organisms, and how cells work together to form tissues, organs, and organ systems.
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3.1 Discovering Cells 7.1 All living organisms are composed of cells, from just one to many trillions, whose details usually are visible only through a microscope
An Overview of Cells • Key concept: Cells are the basic units of structure and function in living things. • Examples of function: obtaining oxygen, getting rid of waste, obtaining food, growing, and more… • Cells function similarly in all organisms, they carry out the basic processes of life similarly • Cells are so small they are measured in micrometers • One square centimeter of Skin is more than 100,000 cells • Cells are visible only through microscope
First Observations of Cells • 1590ish invention of the microscope • Key concept: The invention of the microscope made it possible for people to discover and learn about cells. • Robert Hooke • one of first people to observe cells • built his own microscope- one of the best of his time • observed cork which looked like small rectangular rooms they called cells
First Observations of Cells Anton van Leeuwenhook • Dutch businessman • Built simple microscopes in his spare time • Looked at drops of lake water, scrapings from teeth and gums, water from rain gutters Animalcules- means “little animals,” small organisms that moved that he found in things like lake water
Development of the Cell Theory • Schleiden- all plants are made of cells • Schwann- all animals are made of cells • Virchow- new cells are formed only from cells that already exist • Until these men’s time people believed that cells can come from non-living matter
Cell Theory An explanation of the relationship between cells and living things • All living things are made of cells. • Cells are the basic units of structure and function • All cells are produced from other cells
Unicellular and Multicellular • Unicellular- single celled • Multicellular- many cells • Key concept: “In multicellular organisms, cells are often organized into tissues, organs, and organ systems. • Tissue- a group of singular cells that work together • Organs- is made up of different kinds of tissue • Organ system- a group of organs wanted to what those