Cell Theory & What Makes Cells “Cells”

1. In the beginning… The first person to actually see cells was a man named Robert Hooke. In 1665, he was using a very early version of the microscope that looked something like this, to look at tree bark.

2. In the beginning… What he saw looked something like this: Because the structures that made up the tree seemed to be like little rooms, he called them “cells” and the name stuck.

What Robert Hooke observed…

3. Cell Theory Since Hooke’s observations many scientists have examined living things and come to 3 basic conclusions. Cell Theory All living things are made of cells. Cells are the basic building blocks and machines of living things. New cells are made from already existing cells.

The Wacky History of Cell Theory http://ed.ted.com/lessons/the-wacky-history-of-cell-theory Notes:

4. Present Day This is a diagram of the cell as we know it today.

5. Cell Diversity Cells come in a range of shapes and sizes that are determined by cell function. 8

6. Cells are a part of a system TISSUES ORGANS SYSTEMS 9

7. Basic Cell Information - Common Characteristics Cells are the basic unit of life. Cells come in different shapes, sizes, and functions. Cells contain internal structures, called organelles. Organelles are specific structures that perform a specific function. 10

8. Cells exhibit basic structural similarities Cells contain a semi-fluid component called the cytoplasm that fills the interior of the cell. 11

9. Cells exhibit basic structural similarities continued… Cells contain cell membranes that enclose a cell and separate its components from its surroundings. 12

10. Cells exhibit basic structural similarities continued… Cells contain DNA, a nucleic acid that contains the genetic information for the organism. In all cells the DNA is centrally located in the cell. In some cells the DNA is located in the nucleus. Some cells do not have a nucleus. 13

11. Prokaryotes vs. Eukaryotes Not all cells are exactly alike! They have different structures, shapes and sizes due to their function. Prokaryotic cells and Eukaryotic cells are two types of cells that are different from each other. 14

12. Prokaryotic Cells Prokaryotes are less complex and smaller in size. Genetic material not contained in nucleus. The DNA located in cytoplasm. There are no membrane-bound organelles in prokaryotes. Examples: Bacteria and Archae 15

13. Image of Prokaryotic Cell 16

14. Eukaryotic Cells Eukaryotes are more complex and larger in size. Genetic material (DNA) is contained in nucleus. There are membrane-bound organelles in eukaryotes. Examples: Protists, Plants and Animals 17

15. Plant vs. Animal Cells There are more similarities between plant and animal cells than differences. Similarities: nucleus, plasma membrane, mitochondria, golgi apparatus, rough and smooth ER, ribosomes, vesicles, cytoskeleton Differences: Animal cells contain lysosomes, flagellum, cilia, centrioles Plant cells contain large central vacuole, chloroplast, cell wall 18

16. Image of Plant Cell 19

17. Image of Animal Cell 20