1. Cell Theory

2. Discovery of the Cell
Robert Hooke ( ) – invented the term cell; studied dead plant cells such as cork.
Anton van Leeuwenhoek ( ) - 1st to observe living cells.

3. Invented the microscope
van Leevheohoek
Invented the microscope

4. Came up with the name “cells”
Robert Hooke
Came up with the name “cells”

5. Discovery of the Cell
Matthias Schleidan ( ) – concluded that all plants are composed of cells.
Theodor Schwann ( ) - concluded all animals were composed of cells.
Rudolf Virchow (1821 – 1902) - reasoned that cell come only from other cells.

6. “All plants are made up of cells”
Schleiden
“All plants are made up of cells”

7. All animals are made up of cells
Schwann
All animals are made up of cells

8. All cells come from pre-existing cells
Virchow
All cells come from pre-existing cells

9. 1) All living things are made of cells
CELL THEORY
1) All living things are made of cells

10. CELL THEORY
2) Cells are the basic unit of structure and function for all living things

11. 3) Cells come from pre-existing cells
CELL THEORY
3) Cells come from pre-existing cells

12. Microscopes provide windows to the world of the cell
The light microscope enables us to see the overall shape and structure of a cell
Image seen by viewer
Eyepiece
Ocular lens
Objective lens
Specimen
Condenser lens
Red blood cells
teaching.path.cam.ac.uk/partIB_pract/NHP1/
Light source
Figure 4.1A
Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

13. websemserver.materials.ox.ac.uk/cybersem/getf...
Electron microscopes
Invented in the 1950s
They use a beam of electrons instead of light
The greater resolving power of electron microscopes
allows greater magnification
reveals cellular details
websemserver.materials.ox.ac.uk/cybersem/getf...

14. Scanning electron microscope (SEM)
Used to see detailed structure of cell surface
Red blood cells
Figure 4.1B
Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

15. Transmission electron microscope (TEM)
Used to examine the internal structures of a cell
Red blood cell in capillary
commons.wikimedia.org/wiki/Image:A_red_blood_...
Figure 4.1C
Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

16. Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings
Cell size and shape relate to function
Figure 4.2
Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings

17. Different kinds of animal cells
white blood cell
red blood cell
cheek cells
sperm
nerve cell
muscle cell
Amoeba
Paramecium

18. Levels of organization
Cells are grouped together and work as a whole to perform special functions

19. Tissue A group of similar cells to perform a particular function
Animals : epithelial tissue, muscular tissue
Plants : vascular tissue, mesophyll

20. Organ
Different tissues group together to carry out specialized functions
Heart : consists of muscles, nervous tissue and blood vessels
Leaf : consists of epidermis, mesophyll and vascular tissue

21. The Structures of a Leaf (Plant Organ)
Chloroplast
Palisade Mesophyll Cell
Spongy Mesophyll Cell
Air Space
Stoma

22. The Structures of a Heart (Animal Organ)

23. System
Several organs and tissues work together to carry out a particular set of functions in a co-ordinated way
Human : digestive, respiratory, excretory, circulatory and reproductive systems
Plant : root and shoot systems

24. Levels of Organization
CELLS (muscle cells,nerve cells)
TISSUES (muscle, epithelium)
ORGANS (heart, lungs, stomach)
SYSTEMS (circulatory system)
ORGANISM (human)

25. Natural laws limit cell size
At minimum, a cell must be large enough to house the parts it needs to survive and reproduce
The maximum size of a cell is limited by the amount of surface needed to obtain nutrients from the environment and dispose of wastes

26. A small cell has a greater ratio of surface area to volume than a large cell of the same shape
Surface area of one large cube = 5,400 µm2
Total surface area of 27 small cubes = 16,200 µm2
Figure 4.3
Copyright © 2003 Pearson Education, Inc. publishing Benjamin Cummings