Lesson 1 discovering the cell
- 1. LESSON #1 What is so extraordinary about the organization of living organisms?
- 2. DISCOVERING THE CELL The unit of life
- 6. How were cells discovered?
- 7. Discovering the principles of the microscope In 1590, Zacharias Janssen, a Dutch eyeglass maker. 2 overlapped lenses increase magnification
- 8. Anton Van Leewenhoek (1632- 1723) Father of microbiology First to observe living organisms smaller than what the human eye can see.
- 9. Robert Hooke Scientist Made an improved microscope. First used the word “cell” to indicate what living beings are made of.
- 10. What Hooke saw…
- 11. A pause In the following years Hooke’s discovery didn’t have much influence in science. S. XVII y XVIII Scientists were focused on classifying new species discovered by explorers.
- 12. In the early 19th Century they had a revolutionary idea in Germany. Living things are made of living units They started studying plants and animals at a microscopic level again.
- 13. Both came up with a theory that said that all organisms come from a cell and develop from there by the formation of new cells. CELL THEORY. 18381839
- 14. All living things are formed by one or more cells A cell is the smallest and simplest living thing. All cells come from other pre-existing cells. All cells can function independently, although they work together in a coordnated way when part of an organism. One cell can perform all living functions : nutrition, reproduction and interrelation
- 15. How large are things really? Microscopic objects are meassured in: μm = 10-3 mm Nm = 10-6 mm Not visible with a naked eye. Eye resolution is 0,2 mm If two objects are separated by a smaller distance, we will see them as one. Exercise 1: If an object meassures 1 mm, how many micrometers does it meassure? And how many nanometers?
- 16. Exercise 2 Paramecium caudatum magnified 300 times 3.6 cm What is the size of the paramecium? Could we see it with our naked eye?
- 17. 20th Century interest: The cell 1930 invention of the Electron Microscope: uses electrons instead of light. Resolution 0,5 nm. Allows to see cells in detail.
- 18. Electron Microscope Images What do you think this is? And this?
Editor's Notes
- #6: By the beginning of the XIX century scientists already described living organisms as being organized in different levels. systems, organs, tissues and an inferior level. The last level of organization was apparently disorganized or shapeless appearance.
- #8: Dutch eyeglass maker, first discovered the principles of the microscope: 1590, Zacharias Janssen He saw that by putting two lenses together in a tube you could see things highly enlarged.
- #9: Worked in a dry goods store (sold cloths). He grinded and polished tiny lenses…the best known at the time. They used them to count threads. His first important discovery was the existance of living things in the water…microorganisms. He observed numerous substances and recorded all his findings, writing letters to the Royal Society of England and France. Observed blood, semen, water…etc He was the first to see and describe bacteria, corpuscules in the blood, and living organisms swimming in water.
- #10: In 1665 improved Leewenhoek’s miscroscope and observed through a complex microscope a piece of cork. He described what he saw as a structure similar to a bee hive and he called each compartment “cell”. What he was looking at were dead cells.
- #19: Scanning electron micrograph (SEM) of various Pollen