1. Unit TWO- Chapter 3 Cell Structure Mrs. Cook Biology

2. History of the Microscope Robert Hooke- 1665- used an early light microscope to look at slice of cork from an oak tree. What he saw looked like little boxes that he called “cells” He noticed that the cells of trees, roots and stems looked similar.

3. Anton Van Leeuwenhoek 1673- Dutch scientist observed first living cells- “microorganisms”. Invented the microscope. observed cells from algae called spirogyra and bell- shaped cells on stalks of protists called vorticella. called these organisms “beasties” and then formally “Animacules” we now call them Protists.

4. History of the Microscope http://www.youtube.com/watch?v=XgW1HiV9SJs http://www.youtube.com/watch?v=XgW1HiV9SJs

5. The Cell Theory 1838, German Botanist- Matthais Schleiden said that all plants were made of cells. 1839, German Zoologist, Theodor Schwann said the same thing for animals. The German Physician, Rudolf Virchow (1821-1902), said that all cells come from other cells.

6. The Cell Theory These ideas were combined to form a basic theory about the cellular nature of life called The Cell Theory. 1.All living things are made of one or more cells. 2.Cells are the basic units of structure and function of organisms. 3.All cells arise from existing cells. Note: somatic cells = body cells gametes = sex cells (sperm and eggs)

7. The Cell Theory Song… http://www.youtube.com/watch?v=KuJqqiATlqw

8. All living things include the following characteristics ORGANIZATION METABOLISM CHANGE WITH TIME RESPOND TO STIMULI REPRODUCTION MAINTAIN HOMEOSTASIS GROWTH & DEVELOPMENT

9. Microscopes The continuous development of microscopes has helped scientists to clarify our definition of life. Compound Microscope Scanning electron Microscope

10. Microsopes cont. Light microscope: light passes through one or more lenses to produce an enlarged image. Electron microscope: forms an image using a beam of electrons rather than light. Parts of a microscope: Magnification- is the quality of making an image appear larger than the objects actual size. Resolution- is a measure of the clarity of an image

12. Compound Light microscope

13. Cell Features We have trillions of cells that range from 5 nanometers in size to 20 nanometers. So, Why do we have trillions of little cells instead of fewer larger cells? This has to do with surface area to volume ratio. Smaller the cell, the quicker it can get substances into the cell and to the area that needs them. The larger the cell, the longer it would take for the substances to travel through the cell.

14. http://youtu.be/wuXSEOKNxN8

15. Cell Features cont. http://youtu.be/o1GQyciJaTA http://youtu.be/o1GQyciJaTA All cells share 3 common features: 1.Cell Membrane (aka plasma cell membrane)- - the cells outer boundary -acts as a barrier between the inside and the outside of the cell - All materials must enter or exit through this castle walls Gates to Turnpike

16. Cell Features Cont. 2 nd feature common to all cells: 2. Cytoplasm- - the region inside the cell membrane that includes all fluids (Cytosol), organelles (tiny organs), and the nucleus.

17. Cell features cont. 3 rd feature common to all cells: 3. DNA -all cells have DNA for regulating function and reproduction. - DNA in some cells floats freely - Other cells have a membrane bound organelle, that contains the cells DNA, called the Nucleus.

18. Two Basic Types of Cells Prokaryotes Smallest and simplest cells Single celled organisms (bacteria, amoebas) Lacks a nucleus, has circular DNA No organelles Has a protective cell wall surrounding its cell membrane. Gives the cell structure, stability, and shape. Most have flagella- long threadlike structures that protrude from the cell’s surface for movement.

20. Second Type of Cell Eukaryotic Cells cells that have a nucleus - Nucleus -internal compartment that holds the cell’s DNA - Control center for the cell Has specialized structures called organelles. - Organelles- well defined structures that carry out specific functions within the cell. - located inside the cell membrane and outside the nucleus Cilia- some single celled Eukaryotes contain them to move around- short hair like flagella.