1. Chapter 3, Section 1
The Diversity of Cells

2. Different populations
BIOME/
ECOSYSTEM
COMMUNITY
POPULATION
___________  __________ ___________
All the organisms
of one species in
an area
Different populations
interconnected
IMAGE SOURCES: see last slide

3. ___________  __________ ___________
ORGAN SYSTEMS
ORGANISM
ORGANS
___________  __________ ___________
Different tissues working together
Different organs working together
IMAGE SOURCES: see last slide

4. ____________  ____________
TISSUES
CELLS
____________  ____________
Similar cells working together
IMAGE SOURCES: see last slide

5. What is a Cell????
A cell is the smallest unit in a living thing that can perform all of the functions necessary for life

6. Robert Hooke 1665- ______________________
used a microscope to examine a thin slice of cork and saw “little boxes”
Robert Hooke
He called them “CELLS” because they looked like the small rooms that monks lived in called Cells
Microscope image: Cork image:
Hooke image:

7. Anton van Leeuwenhoek 1673- ___________________________________
a Dutch microscope maker was the first to see LIVING ORGANISMS.
Anton van Leeuwenhoek
Microscope/Leeuwenhoek image: Animation from:

8. Overview of Cell Theory History
Lets Read
an Article!

9. 1838- German botanist __________________________concluded that
ALL PLANTS
are made of cells
Matthias Schleiden
Plant image: Schleiden image:

10. Theodor Schwann 1839- German zoologist
_________________________concluded that
Theodor Schwann
ALL ANIMALS ARE MADE OF CELLS
Schwann image:
Animals image:

11. The Cell Theory Schwann wrote the first two parts of the cell theory
All organisms are made of one or more cells
The cell is the basic unit of all living things

12. Rudolph Virchow 1855- German medical doctor _____________________
saw dividing cells
in the microscope
and reasoned that
cells come from
other cells
Rudolph Virchow
Virchow:
Mitosis:

13. CELL SIZE
The yolk of an egg is a single cell!
50 human cells could fit on the dot of the “i” in your textbook!
Typical cells range from: 5 – 50 micrometers (microns) in diameter

14. The answer has to do with the cell membrane. Balloon Demo
Why Are Cells So Small?
One characteristic of cells is that they are very small. Why are cells so small?
The answer has to do with the cell membrane.
Balloon Demo

15. Cells Need a Large Surface Area
Everything the cell needs to take in or has to get rid of has to go through the cell membrane.
Therefore the cell membrane needs to have a large surface area in relation to the volume of the cell.
As a cell gets bigger, so does its surface area.

16. However, the volume of a cell increases at a faster rate than the surface area of its cell membrane.
If a cell gets too large, its cell membrane will not have enough openings to meet the demands of its volume.
This limits the size of cells.

17. Parts of a Cell
All cells, no matter what size or shape have the following:
Cell membrane and cytoplasm
Organelles
Genetic material

18. Two Kinds of Cells There are two basic types of cells:
Prokaryotes (which include bacteria and archaebacteria)
Eukaryotes

19. Prokaryotes
Even though these organisms have DNA, they do not have a nucleus (we’ll study this soon!!!!)
Bacteria
Bacteria are everywhere
Bacteria are unicellular
Have ribosomes
(we’ll study these later!!!)

21. Archaebacteria - are similar to bacteria, but their ribosomes are different and they live in some pretty extreme places, like near volcanic vents or even in sewage!

22. Prokaryotic Cell

23. Eukaryotes Eukaryotic cells are the largest cells
Eukaryotes have a nucleus
Most are multicellular