The Cell Theory

The Players There are several scientists that contributed to the establishment of the cell theory Collaboration Two or more people work together for a common goal

The Players Hans & Zacharias Jenssen Robert Hooke Antony van Leeuwenhoek Matthias Schleiden Theodor Schwann Mohl & Schultze Rudolf Virchow

Contributions 1. Hans (father) & Zacharias (son) Jenssen created the first compound microscope Able to magnify objects about 7x their actual size 1595

Contributions 2. Robert Hooke was known for his observations and publications dealing with both microscopy and astronomy In 1665 Hooke made observation of a thin slice of cork (tree bark) & drew them Saw small compartments that he called cellulae (latin for “cells”) Looked like the rooms (cells) of a monastery

Can You See What Hooke Saw? 6

Contributions 3. Antony van Leeuwenhoek made over 500 simple (as opposed to compound) microscopes around 1670 Excellent lens grinder Simple scopes could magnify 200x Observed anything that he could find First to see living cells under microscope

POND WATER…….SAW Micro-organisms……Single Celled. 8

Contributions 4. Matthias Schleiden was a botanist that came to a very important conclusion in 1838: Observed plant tissues from multiple species Realized that all plants are made of cells

Plant Cell

Contributions 5. Theodore Schwann was a zoologist and a good friend of Schleiden Heard about Schleiden’s findings Schwann had observed that all the animals he observed were made of cells in 1839

Animal Cell

Schleiden and Plants When you weed your garden, you are uprooting plants from the soil. Schleiden was the first scientists to say that those plants are made up of cells. 13

Schleiden is Weedin’ 14

Schwann and Animals Schwann was the first scientists to say that all animals are composed of at least one cell. 15

Together… All living things are composed of cells! 16

Contributions 6. Mohl & Schultz 1839 Developed the idea that cells are the basic unit of living things Nothing that is alive is simpler than a cell

Contributions 7. Rudolf Virchow studied and taught medicine Noticed all cells always came from preexisting cells (1855)

Cell Theory The Cell Theory By the end of the 19th century, all of these ideas and concepts were widely accepted. Collectively, they became known as: The Cell Theory 19

Summary of the Cell Theory (19th Century) 1. All living things are made of one or more cells. Plants and animals are composed of cells and of products made by cells. 2. Cells are the basic units of structure and function in organisms. Living things carry on their activities because of the activity of their component cells. 3. All cells arise from pre-existing living cells. 20

Summary of the Cell Theory (Added in the 21st Century) 1. All cells are made basically the same way They all have the same basic organelles in basically the same place within the cell. Even cells from other organisms are basically the same as your cells 2. Energy flows within cells The final break down of food occurs within your cells. Cells are able to harvest energy from food and use energy to drive activities. 3. Cells contain hereditary information (DNA) that must be passed to new cells when they divide. Every cell has DNA as its molecule of heredity, and it passes DNA on to every new cell that is formed. 21