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Understanding Cells Have you ever looked up at the night sky and tried to find other planets in our solar system? It is hard to see them without using a telescope. This is because the other planets are millions of kilometers away. Just like we can use telescopes to see other planets , we can use microscopes to see the basic unit of all living things, cells.
Understanding Cells • But people didn’t always know about cells. Because cells are so small, early scientists had no tools to study them. It took hundreds of years for scientists to learn about cells. • More than 300 years ago, an English scientist named Robert Hooke built a microscope. He used the microscope to look at cork cells , which are found in the bark of the Cork Oak tree. What he saw looked like the openings in a honeycomb. The openings reminded him of the small rooms monks stayed in so he named the cells.
Understanding Cells • After Hooke’s discovery, other scientists began making better microscopes and looking for cells in many other places such as in pond water and blood. The newer microscopes enabled scientists to see different structures inside the cells.
Understanding Cells • Matthias Schleiden , a German scientist, used one of the new microscopes to look at plant cells. Around the same time, Theodor Schwann used a microscope to study animal cells. Schleiden and Schwann realized that plant and animal cells have similar features that carry on similar functions, such as extracting energy from food and eliminating wastes. From this evidence, Schleiden and Schwann concluded that cells are the basic unit of life.
Understanding Cells • Almost two decades later, Rudolph Virchow, a German doctor, proposed that all cells come from existing cells. The observation made by Schleiden, Schwann and Virchow were combined into one theory. The cell theory states that all living things are made of one or more cells, the cell is the smallest unit of life, and all new cells come from pre-existing cells.
ROBERT HOOKE • 1655 • First observed cells of cork under a very primitive microscope. • Named them “cells” because they reminded him of the cells that monks lived in • Word cell is Latin for small compartment
Anton van Leeuwenbock • 1670 - Looked at pond water under a microscope and was the first to see living cells
Anton van Leeuwenbock • 1683 • Sees first protozoa and bacteria under a microscope
Robert Brown • 1833 - English botanist nucleus in plant cells
Matthias schleiden 1838 – First to determine that all plants are made of cells
Theodore schwann • 1839 • Discovered that all animals are made of cells • Responsible for discovery of enzyme pepsin • Wrote the first cell theory that stated • Cells are organisms and all organisms are made of at least one cell • The cell is the basic unit of structure of all organisms
Albrecht von kollicker • 1840 • Swiss embryologist who first discovered that eggs and sperm are cells
Carl heinrich braun • 1845 • Botanist who reworked Schwann’s cell theory stating that cells are the basic unit of life
Rudolph virchow • 1855 • Concluded that all cells are made form existing cells • New cells form from the division of existing cells • Called the Father of Pathology
