The Cell Theory

1. The Cell Theory

2.  Robert Hooke (1665) • English scientist. • Developed the first compound microscope.

3.  Robert Hooke • In 1665, he used his microscope to look at cork cells. • Hooke coined the term “cell” • What he saw under the microscope reminded him of the living quarters of the monks (cells).

4.  Anton van Leeuwenhoek(1674) • Dutch curtain maker who ground lenses as a hobby. • Improved and perfected the microscope. • The first to observe living cells • (blood cells and bacteria from his teeth.)

5.  Mathias Schleiden(1837) • German Botanist • Observed that all plants are made up of cells.

6.  Theodor Schwann(1837) • German Zoologist • Observed that all animals are made up of cells.

7.  Rudolf Virchow (1858) • German Doctor • The first to observe living cells reproduce. • Deduced that animal cells come only from animals, plant cells come only from plants.

8.  Robert Brown (1833) • Scottish botanist • First to see the nucleus

9.  The Cell Theory • The observations of these scientists led to the cell theory. The modern cell theory has 3 parts: • Cells are the basic units of life • All living things are made of one or more cells. • All cells come from preexisting cells.

10.  Organization of Life • Organisms can be single-celled or multicellular. • Multicellular organisms are organized into complex structures. • Multicellular organisms have specialized cells to perform a single function. • Ex. Red blood cells carry oxygen; muscle cells provide movement.

11.  COMBINE TO FORM Molecules

12.  COMBINE TO FORM Red blood cells Cells

13.  COMBINE TO FORM Cardiac muscle Tissues

14.  COMBINE TO FORM Organs Heart

15.  COMBINE TO FORM Systems Circulatory System

16.  COMBINE TO FORM Organisms

17.  Ecosystems

18.  Types of Cells • Prokaryotic cells – primitive cells that have little internal structure. • Eukaryotic cells – evolved from prokaryotic cells and contain numerous internal structures. • Organelles– structures in the cell responsible for carrying out specific functions. “cell organs”

19.  Prokaryotic Cells • Prokaryotic cells do not contain a nucleus or any membrane bound organelles. • They are always single-celled organisms. • Ex. Bacteria • Very simple structure – cell wall and membrane surrounding cytoplasm. • Divide by binary fission

20.  Eukaryotic Cells • Eukaryotic cells contain a nucleus and membrane-bound organelles. • Can be single-celled or multicellular organisms. • Ex. Algae (single) or plants (multi) • Divide by mitosis

21.  What limits cell size? Surface Area to Volume Ratio • As a cell increases in size, its volume increases faster than its surface area

22.  What limits cell size? Manage Resources: • A cell must be able to fill its volume with nutrients and empty its volume of wastes

23.  What limits cell size? Regulate Cell Functions (DNA  Proteins) • DNA must be able to control protein production. Larger cells would not have enough DNA to produce enough proteins for the cell’s normal functions

24. Another Way To Look At It: • Each tiny cube (cell) is better able to exchange nutrients and wastes than the big cube