The document summarizes key concepts about cells including their discovery, organization of life, and cell theory. It describes how Robert Hooke first observed cells using a microscope in 1665 and how Anton van Leeuwenhoek later observed bacteria and other microorganisms. It also outlines how Matthias Schleiden and Theodor Schwann developed the cell theory, concluding that all organisms are composed of cells, cells are the basic unit of life, and all cells come from preexisting cells. The document also distinguishes between prokaryotic and eukaryotic cells.

1. Cells Organization of Life Discovery of Cells Cell Theory Prokaryotic vs. Eukaryotic

2. Organization of Life Put your cards in order from least complex to most (what is made from what?) Cell Tissue Organ Organ System Organism

3. Organization of Life Cell Tissue Organ Organ System *Organism can be made of one cell or many organ systems. Smallest unit that can carry out life’s activities Group of cells working together to perform specific job Group of tissues working together to perform specific job Group of organs working together to perform specific job Organism*

4. Discovery of Cells Most cells cannot be seen with naked eye So how were they first discovered? What was needed for their discovery?

5. Cells Discovered 1665 - Robert Hook discovered cells by accident Hook built a basic microscope to look at small things Looked at cork from a tree

7. Discovery of Cells 1673 - Anton van Leeuwenhoek looked at pond scum and saw small creatures Leeuwenhoek also saw that blood cells differed between animals, saw bacteria, and realized that yeast was alive 1838 – Schleiden concluded that all plant parts are made of cells 1839 – Schwann stated all animal tissues are made of cells

10. Cell Theory 1839 - Schwann developed beginning of CELL THEORY All organisms are composed of one or more cells. The cell is the basic unit of life in all living things. 1858 – Virchow added to CELL THEORY All cells come from existing cells Make a timeline of Cell Discovery

11. All Cell’s Have… Cell membrane – barrier between inside and outside of cell; controls passage of things in and out of cell Hereditary material – all cells contain DNA and pass a copy to new cells Organelles – all cells have chemicals and structures that let the cell live, grow and reproduce Cytoplasm - a fluid surrounding their structures

13. Classification of Cells Cells Animal Cells Plant Cells Bacteria Eukaryotic Prokaryotic Other Cells Unicellular Organisms Multicellular Organism Other Cells

14. Two Types of Cells Prokaryotic – no nucleus Eukaryotic – have a nucleus

15. Prokaryotic Bacteria Smallest cells No nucleus Long, circular DNA Probably first type of cells on Earth (3.5 billion years old fossils)

16. Eukaryotic More complex All living things (except bacteria) are made of one or more eukaryotic cells Have nucleus and many membrane-covered organelles Nucleus stores linear DNA All have cell membrane, some have cell wall also