Microscope-and-Cell-Theory (1).pdf

WELCOME TO GENERAL BIOLOGY 1  What is a microscpe ? Microscope - an optical instrument used for viewing very small objects, such as mineral samples or animal or plant cells , typically magnified several hundred times.  TWO TYPES OF MICROSCOPE 1. Simple Mic...

WELCOME TO GENERAL BIOLOGY 1  What is a microscpe ? Microscope - an optical instrument used for viewing very small objects, such as mineral samples or animal or plant cells , typically magnified several hundred times.  TWO TYPES OF MICROSCOPE 1. Simple Microscope 2. Compound Microscope  SIMPLE MICROSCOPE is nothing but a single biconvex lens. It is referred to as a MAGNIFYING GLASS. the object to be viewed in simple microscope is placed between the optic center and the focus. image formed is erect, virtual and magnified. COMPOUND MICROSCOPE HISTORICAL DEVELOPMENT OF THE MICROSCOPE 1590- Hans Janssen and his son Zacharias Janssen, placed multiple lenses and found out that the objects through the tube appear greatly enlarged. HISTORICAL DEVELOPMENT OF THE MICROSCOPE 1609- Galileo Galilei invented a compound microscope using convex and concave lenses. HISTORICAL DEVELOPMENT OF THE MICROSCOPE 1625- the first term microscope was used by Giovanni Faber to refer to the compound microscope of Galilei. HISTORICAL DEVELOPMENT OF THE MICROSCOPE 1665- Robert Hooke , an English physicist, coined the term cell in his publication Micrographia. -He was the first to see a plant cell under a single microscope. -the English Father of Microscopy HISTORICAL DEVELOPMENT OF THE MICROSCOPE 1676- Antonie van Leeuwenhoek Was the first to see living cells using his own single lens microscope. He examined blood cells, yeast and insects.  MODERN MICROSCOPE TRANSMISSION ELECTRON MICROSCOPE (TEM) PRACTICE TEST CELL THEORY 1665 ROBERT HOOKE- observe cells in cork.Coined the term “cells” 1827-33 ROBERT BROWN- noticed that pollen grains in water jiggled around called “ Brownian motion”- - discovered nucleus 1838- MATTHIAS SCHLEIDEN- a botanist who concluded that all plants are made of cells. 1839 THEODOR SCHWANN- a zoologist who concluded that all animals are made of cells. 1855 RUDOLPHVIRCHOW- a physician who did a research on cancer cells and concluded “Omnis cellula e cellula “ All cells are from pre-existing cells. CELL THEORY formally established by Theodor Schwann and Matthias Schleiden in 1839. The most basic tenet underlying the field of biology. one of the basic principles of biology. Formulated by the 3 German scientists Theodor Schwann, Matthias Schleiden and Rudolph Virchow.  CELL THEORY 1.Cells are the smallest unit of life. All living things are composed of one or more cells. 2. Cells are the basic unit of organization of all organisms. 3. Cells come only from pre-existing cells.  MODERN CELL THEORY 1.Cells carry and pass on to the offspring hereditary units during cell division. 2. All cells are relatively the same in terms of chemical composition and metabolic activity. Cell size  CELL SHAPE The shape of the cell varies in different organisms. The shape of plant cell is different from that of an animal cell. They may be: -Spherical - polygonal -Oval - columnar or flat plate- like -Elliptical -Spindle shaped -cuboidal