5Anton van LeeuwenhoekIn the mid 1600’s Leeuwenhoek is thought of as discovering the first practical microscopes.Leeuwenhoek in 1674 was the first to see1. bacteria, yeast, and plants2. life in a drop of water3. circulation of blood corpuscles incapillaries
6Discovery of Cells1665- English Scientist, Robert Hooke, discovered cells while looking at a thin slice of cork (dead cells from oak bark).He described the cells as tiny boxes or a honeycombHe thought that cells only existed in plants and fungi
7Development of Cell Theory 1838- German Botanist, Matthias Schleiden, concluded that all plant parts are made of cells1839- German physiologist, Theodor Schwann, who was a close friend of Schleiden, stated that all animal tissues are composed of cells.
8Development of Cell Theory 1858- Rudolf Virchow, German physician, after extensive study of cellular pathology, concluded that cells must arise from preexisting cells.
9The Cell Theory Complete The 3 Basic Components of the Cell Theory were now complete:1. The cell is the basic unit of life in all living things.2. All organisms are composed of one or more cells.3 All cells are produced by the division of preexisting cells.
10Prokaryotic vs. Eukaryotic Scientists have found two basic types of cells:1. Prokaryotic cells are those that have no membranearound their nuclear material.Example include bacteria and pond scum cells.Involved in - cell division
11Bacterial CellsUnlike plant and animal cells, bacterial cells are prokaryotic.They do not have membrane- bound organelles, nor nuclei.They do have:ribosomes, a single chromosome, a cell wall, and cytoplasm.Reproduction: asexual or sexual?Good and bad bacteria?
122. Eukaryotic cells have a membrane bound nucleus. Animal and plant cells are eukaryotic.
13Animal Cells Animal cells are eukaryotic Every cell in your body is constantly activeand has a specific function.For example, a nerve cell has a job that is much different than a muscle cell.Each cell has several structures inside, andeach structure has a specific job.These structures are called organelles.
14Plant Cells (eukaryotic) The major difference between a plant cell and an animal cell is that plant cells have cell walls.A cell wall is a rigid structure outside thecell membrane that supports and protectsthe plant cell.
15Plant cells continued: 2. Plants also differ from animal cells because they can make their own food.3. Organelles called chloroplasts convert light energy into chemical energy in the form of sugar.4.One of the chemicals in chloroplasts, chlorophyll, traps light energy
16Organization of CellsA one-celled organism (unicellular) performs all of life’s functions by itselfAn example is bacteriaA multicellular organism, however, does not work independently.Each cell depends on other cells to carry on all of life’s functions.In a multicellular organism, cells are organized into tissues.Tissues are groups of similar cells that do thesame sort of work.Cells->Tissues- >Organs -> Organ system -> Organism