A. cells introduction
- 2. • Zacharias Janssen - made 1st compound microscope • a Dutch maker of reading glasses (late 1500’s)
- 3. Robert Hooke • (18 July 1635 – 3 March 1703) • Philosopher, architect and physicist • played an important role in the scientific revolution through both experimental and theoretical work • known for his law of elasticity • applying the word “cell" to describe the basic unit of life.
- 4. Cork cells
- 5. Leeuwenhoek • made a simple microscope (mid 1600’s) • magnified 270X • Early microscope lenses made images larger but the image was not clear
- 6. • He is best known for his contribution to improvement of the microscope • and his contributions towards the establishment of cell biology. • he was the first to observe and describe muscle fibres, bacteria, spermatozoa and blood flow in capillaries • His microscope was used and improved by Christiaan Huygens for his own investigations into microscopy.
- 7. Leeuwenhoek's microscope A) a screw for adjusting the height of the object being examined B) a metal plate serving as the body C) a skewer to impale the object and rotate it D) the lens itself, which was spherical
- 8. van Leeuwenhoek’s microscopes were three to five times stronger than Hookes allowing up to a magnification of 200 times. enough to see one-celled animals and even, as moving dots, bacteria.
- 9. • A simple microscope has one lens • Similar to a magnifying glass • Magnification is the change in apparent size produced by a microscope
- 10. Light Microscope
- 12. TOTAL MAGNIFICATION • Powers of the eyepiece (10X) multiplied by objective lenses determine total magnification.
- 13. Resolution the ability to tell two points apart as separate points. • If the resolving power of your lens is 2um that means two points that are 2um apart can be seen as separate points • If they are closer together than that, they will blend together into one point. • The magnification is the ability to make an object larger. • If the resolving power of a microscope is poor, it will just magnify a blurry object..
- 16. ELECTRON MICROSCOPES • More powerful; some can magnify up to 1,000,000X • Use a magnetic field in a vacuum to bend beams of electrons • Images must be photographed or produced electronically
- 19. Scanning Electron Microscope (SEM) Electron microscope image of a spider • produces realistic 3D image • only the surface of specimen can be observed Electron microscope image of a fly foot
- 20. Transmission Electron Microscope (TEM) • produces 2D image of thinly sliced specimen • detailed cell parts (only inside a cell) can be observed
- 21. CELL THEORY 1. The basic unit of life is the cell. (Hooke) In 1665, an English scientist named Robert Hooke made an improved microscope and viewed thin slices of cork viewing plant cell walls Hooke named what he saw "cells"
- 22. CELL THEORY 2. All living things are made of 1 or more cells. • Matthias Schleiden (botanist studying plants) • Theodore Schwann (zoologist studying animals) stated that all living things were made of cells Schleiden Schwann
- 23. CELL THEORY 3. All cells divide & come from old cells. (Virchow) Virchow
- 24. Animal and Plant Cell Structure
- 25. Liver Cells -EM
- 27. • Click here 1mm = 1000μm 1μ m = 1000nm