2. Chapter 4, Section 1 As if you didn’t already know!

3. 1665 made a compound microscope (a microscope with several lenses) he placed a small piece of cork (tree bark) under his microscope What did he see? the cork looked like hundreds of little boxes next to one another he named these little boxes cell, which means “little room” in Latin. Robert Hooke

4. What did Robert Hooke say to his stockbroker? Cell!

5. Anton van Leeuwenhoek 1673, used his handmade microscope to look at pond water. He saw small organisms in the water. Now we know that these were unicellular organisms like bacteria or protozoa.

6. The Cell Theory Authors: Matthias Schleiden, Theodor Schwann, & Rudolf Virchow 1. All organisms are composed of one or more cells. 2. The cell is the basic unit of life in all living things. 3. All cells come from existing cells.

7. The largest cell in the world is the yolk of an ostrich egg. It’s the size of a baseball!

8. What do all cells have in common? Cell membrane (holds the cell together) Hereditary material (DNA/genes, found in the nucleus in a eukaryotic cell) Cytoplasm (fluid that fills cell) Organelles (structures inside cell)

9. 2 Types of Cells Prokaryotic (bacteria) pro-: before (“before nucleus” in Greek) no nucleus no membrane-bound organelles circular DNA cell wall is present ribosomes are present draw figure 6, page 118.

10. Question: Define bacteria. The rear entrance to a cafeteria!

11. 2 Types of Cells Eukaryotic (protists, fungi, plants, & animals) eu-:true (“true nucleus” in Greek) Nucleus is present Organelles present DNA is linear Cell membrane present Cell walls present only in plants, fungi, and some protists

12. A Comparison Between Prokaryotes & Eukaryotes Eukaryotic cell Has nucleus Membrane-covered organelles Linear DNA All other cells Prokaryotic cell No nucleus No membrane-covered organelles Circular DNA Bacteria

13. Why is it better to be a multicellular organism rather than a unicellular organism?

14. 1. Multicellular organisms can grow. 2. Multicellular organisms are able to do lots of other things because they are made of different kinds of cells. Running = nerve cells, blood cells, muscle cells, bone cells, eye cells