Cell Theory The CELL THEORY states: all organisms are composed of similar units of organization, called cells. The concept was formally written in 1839 by Schleiden & Schwann and remains as the foundation of modern biology.

Cell Theory All known living things are made up of cells. 2. The cell is structural & functional unit of all living things. 3. All cells come from pre-existing cells by division.            

4. Cells contains hereditary information 4. Cells contains hereditary information which is passed from cell to cell during cell division. 5. All cells are basically the same in chemical composition. 6. All energy flow (metabolism & biochemistry) of life occurs within cells.       

Robert Hooke In 1663 an English scientist, Robert Hooke, discovered cells in a piece of cork, which he examined under his primitive microscope. Hooke only observed cell walls because cork cells are dead and without cytoplasmic contents. Hooke drew the cells he saw and also coined the word CELL.

Anton van Leeuwenhoek Ten years later Anton van Leeuwenhoek (1632-1723), a Dutch businessman used his own (single lens) monocular microscopes and was the first person to observe bacteria and protozoa

The Difference Between Plant and Animal Cells

Animal Cells Can not make their own food so they have to eat food Do not go through photosynthesis Animal cells are more round shaped Animal cells have lysosomes Animal cells can not make sugar Animal cells use mitochondria to release energy

Animal cells cont. Animal cells do not have a cell wall We are all made of animal cells Animal cells do not have a large vacuole They do not have chloroplast

Similarities of Animal and Plant Cells They both have a nucleus They both have ribosome's that make protein Animal and plant cells both have Golgi bodies They both have cytoplasm They both have vacuoles that store food, water and waste products.

Plant Cells Plant cells have a cell wall Plant cells have a large vacuole unlike the animal cell Plant cells do not have mitochondria They also do not have lysosome’s Plant cells are in the shape of a rectangle Plant cells go through photosynthesis go

Plant Cells cont. Plant cells have chloroplast Plant cells use chloroplast to store energy They also have cell membranes