1. Introduction to Cells Dragonfly Book: Chapter 7-1 Ms. McCaughan LSHS

2. The Discovery of Cells Cells were not described until 1665……….WHY? 1. Scientists did not begin to use microscopes until the mid-1600’s 2. Most cells are too small to see without the microscope!

3. The Discovery of Cells A.Robert Hooke (1665) 1.English Biologist 2.Observed a thin slice of cork (plant material) using an early microscope 3.Saw thousands of tiny chambers which he called “cells” Draw what he saw in the box

4. The Discovery of Cells B.Anton van Leeuwenhoek (1674) 1.Dutch biologist 2.Observed tiny living organisms in drops of pond water through a simple microscope. C.Matthias Schleiden (1838) 1.German botanist concluded all plants are made of cells D.Theodor Schwann (1839) 1.German biologist stated all animals are made of cells E.Rundolph Virchow (1855) 1.Proposed all cells come from existing cells

5. Cell Theory The discoveries of all of the mentioned biologists formed a fundamental concept in biology known as CELL THEORY 1. All living things are composed of cells 2. Cells are the basic units of structure and function in living things 3. New cells are produced from existing cells

6. Cells have common characteristics A. DNA Genetic material B. Cell Membrane Lipid bi-layer that controls what goes into and out of the cell C. Ribosomes Structures used in protein synthesis D. Cytoplasm The interior of the cell E. Cytoskeleton  Fibers that give cells structure

7. Prokaryotic Cells A.“Pro” = before, “karyotic” = nucleus B.At least 3.5 billion years old C.Simplest and smallest cells D.No nucleus (Nucleiod region in the center to hold DNA) No specialized organelles (Still function as living: grow, reproduce and respond to environment) Examples: Bacteria and blue-green algae

8. Prokaryotic Cells

9. Eukaryotic Cells A. “Eu” = true, “karyotic” = nucleus B. Evolved about 1.5 billion years ago C. Larger and more complex than prokaryotes D. Nucleus (DNA packaged in chromosomes) E. Many specialized organelles F. Examples: Plants, Animals, protist & fungi

10. Eukaryotic Cells Animal Cell Plant Cell

12. Comparison Chart All CellsProkaryotesEukaryotes Found in living things Basic unit of life Produced from existing cells Contain: Cell membrane DNA Ribosomes Cytoplasm Cytoskeleton Older Smaller Simple No nucleus Nucleoid region No specialized organelles Examples: bacteria, algae Newer Larger Complex Nucleus Many specialized organelles Examples: plants, animals, protists, fungi