Download Cell Theory and Scientists

Cell Theory and Scientists
Cell = basic/smallest unit of life
Cell Diversity (Differences)
1. Size – surface area (SA)-to-volume (V) ratio keeps cells small
• If cell continued to grow, it would burst
2. Shape – reflects function of cell (Ex: neurons vs. red blood cells)
3. Internal Organization -Organelles = cell part that performs a specific function
Types of Cells:
1.Prokaryote – simple cells (no nucleus or organelles in the cell membrane)
“Pro”= before; “kary”= nucleus
a. DNA, ribosomes, cytoplasm & cell membrane
b. unicellular (bacteria)
c. tiny in comparison
2.Eukaryote – complex cells
“Eu”= true; “kary”= nucleus
a. has nucleus with DNA & cell membrane bound organelles in the cytoplasm
b. unicellular or multicellular
c. Two types of eukaryotes:
1) Animal
2) Plant
d. Much larger then prokaryote cells
Early Discovery of the Cell
1665 - Robert Hooke used an early compound microscope to look at a nonliving
slice of cork, a plant material.
He saw what appeared to be thousands of tiny empty chambers. He called these
chambers cells... and the term is still used today.
1674 - Anton van Leeuwenhoek used a single-lens microscope to observe pond
water - and revealed a world of tiny living organisms.
He drew illustrations of organisms he found in the human mouth ... we now call
these organisms bacteria.
1838 - German botanist Matthias Schleiden concluded that all plants are made of
cells
1855 - German biologist Theodor Schwann stated that all animals are made of cells
1855 - German physician Rudolf Virchow concluded that new cells can only be
produced from the division of existing cells.
CELL THEORY:
All of these discoveries led to the cell theory which states...
l All living things are made of cells
l Cells are the basic unit of structure and function in living things
l New cells are produced from existing cells