Timeline of Events

1. Timeline of Events The Cell and The Cell Theory Chapter 4: Structure and Function of Cells

2. Microscopes • The first compound microscope was invented by Zacharias Janssen in Middleburg, Holland, around the year 1595. - A compound microscope has two lenses.

3. Jansen’s Microscope

4. Jansen’s Microscope • The Janssen microscope was capable of magnifying images approximately three times when fully closed and up to ten times when extended to the maximum.

5. Light Microscopes • In 1665, Robert Hooke looked at a thin slice of cork from the bark of a cork oak tree. • He described “a great many little boxes” that reminded him of cubicles or “cells”.

6. Robert Hooke’s Drawing

7. Robert Hooke’s Microscope and Drawing

8. Cells • The “little boxes” that Hooke observed were the remains of dead plant cells. • Hooke coined the word “cells” for the structures he saw under the microscope.

9. 1673 Anton Van Leeuwenhoek • In 1673, Van Leeuwenhoek was the first person to view living cells. • He called the organisms “animalcules”. • We now call them protists.

10. Anton van Leeuwenhoek

11. 1827 Karl von Baer • In 1827 Karl von Baer discovered the mammalian egg. • This meant that animals had cells.

12. Plant and Animal Kingdoms • In the 1800’s all organisms were placed into only two kingdoms- the Plant Kingdom and the Animal Kingdom. • 1838: German Botanist Matthias Schleiden concluded that all plants are composed of cells. • In 1839: German Zoologist Theodor Schwann concluded that all animals are composed of cells.

13. All organisms are composed of cells. • Schleiden’s and Schwann’s conclusion led to the first statement of THE CELL THEORY. • All Living things are composed of cells.

14. Rudolf Virchow 1855 • In 1855, Rudolf Virchow had evidence that cells came from other cells. • This was an astonishing statement since in the mid-1800’s, the controversy over spontaneous generation had grown fierce. • Spontaneous generation states that life can simply “appear”.

15. The Cell Theory • All living things are composed of cells. (Schleiden and Schwann) • Cells are the basic unit of structure and function in an organism. • Cells come from the reproduction of existing cells. (Virchow)

16. The first cell structures- organelles • 1857 Kolliker describes mitochondria in muscle. • Mitochondria are structures inside of cells where cellular respiration takes place. • Organelles are cellular structures that perform specific functions.

17. Mitochondria inside of cells

18. 1897 Camillo Golgi • In 1897, Camillo Golgi discovers the Golgi Apparatus. • The Golgi Apparatus is an organelle that is called the “packaging plant”.

19. Electron Microscopes • Electron microscopes contributed to our knowledge of cells. • E. Ruska made the first image producing electron microscope in 1933 and used it to take pictures of gold and copper surfaces.

20. Improving Technology • Improving technology has allowed scientists to unlock the secrets of the cell. • There are two major types of electron microscope: the transmission electron microscope (TEM) and the scanning electron microscope (SEM)

21. 1964 Palade • In 1964 George Palade published his work on the network of membraneous organelles in cells of the guinea pig pancreas. • This network included the rough endoplasmic reticulum, smooth endoplasmic reticulum, the Golgi Apparatus, and lysosomes.

22. 1996 - Cloning • 1996 Researchers in Scotland clone a sheep from the adult sheep cell.

23. 2004 • Tissue engineering used to grow new skin and bone for transplant.

24. Timeline of Events

25. Use this Power Point to create a timeline.

26. Microscopes helped biologists clarify our definition of life. • All living things: • Consist of organized parts. • Obtain energy from their surroundings. • Perform chemical reactions. • Change with time • Respond to their environment • Reproduce

27. The End