1. An Introduction to Cells
Indicator B – 2.1:
Recall the three major tenets of cell theory
Indicator B – 2.3:
Compare the structures and organelles of prokaryotic and eukaryotic cells.

2. Key Concepts Cell Theory Unicellular vs. Multicellular Organisms
Prokaryotes vs. Eukaryotes

3. It is essential for you to know:
All living things are composed of one or more cells.
Cells are the basic unit of structure of all living things.
All presently existing cells arose from previously existing cells.

4. Objectives Recall the major tenets of the Cell theory.
Compare unicellular organisms and multicellular organisms.
Differentiate between prokaryotic cells and eukaryotic cells.

5. Vocabulary Words Please define the following words: cell theory
cytoplasm
organelle
prokaryotic cell
eukaryotic cell

6. The Cell
LIFE IS CELLULAR

7. Before we begin... ATP (adenosine triphosphate) = Fuel
Cells take sugar (glucose) from food and turn it into ATP.

9. The History of Cell Biology

10. The History of Cell Biology
A person who studies cells is called a cytologist.

11. The History of Cell Biology
Anton van Leeuwenhoek
1600’s
Became one of the first people to use a microscope to study nature.
Was the first person to see tiny living organisms in a drop of water.

12. The History of Cell Biology
Robert Hooke
1665
Saw “cells” in a cork under a light microscope.

13. The History of Cell Biology
Matthias Schleiden
1838
Concluded that all plants have cells.

14. The History of Cell Biology
Theodor Schwann
1839
Concluded that all animals have cells.

15. The History of Cell Biology
Rudolf Virchow
1855
Studied cell reproduction

16. The Cell Theory A cell is the basic unit of life.
All of the scientists’ work contributed to what is now called the cell theory:
All living things are composed of one or more cells.
All cells come from previously existing cells.
Cells are the most basic units of life.

17. Prokaryotes & Eukaryotes
Biologists divide
cells into two
categories:
Prokaryotes
Eukaryotes

18. Prokaryotes & Eukaryotes
No nuclei
Have cell membrane, cell wall, plasmid, ribosomes, cytoplasm
Smaller and simpler
Most bacteria and archae
Divide by binary fission

19. Prokaryotes & Eukaryotes
Have a nucleus
Usually bigger and more complex
Cell membrane, cytoplasm, & organelles.
Plants, animals, fungi, and many microorganisms.

20. Unicellular Organisms
Sometimes the cell is the organism.
Do everything that you would expect a living thing to do.
Include both prokaryotes and eukaryotes.
Prokaryotes: bacteria and archae
Eukaryotes: some types of algae, protists, fungi.

22. Multicellular Organisms
Made up of more than one cell.
Cells in multicellular organisms are specialized to perform particular functions within the organism.
This is cell specialization.
Think:
blood cells, hair cells, digestive cells, etc.

24. Levels of Organization
The levels of organization in a multicellular organism are:
individual cells
tissues
organs
organ systems

25. Levels of Organization
Cell: nerve cell
Tissue: nerve tissue
Organ: the brain
Organ System: Nervous System