Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Endomembrane system wikipedia , lookup
Extracellular matrix wikipedia , lookup
Cytokinesis wikipedia , lookup
Cell growth wikipedia , lookup
Tissue engineering wikipedia , lookup
Cellular differentiation wikipedia , lookup
Cell culture wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Cell encapsulation wikipedia , lookup
Grade 10 Applied Science – Biology Cell Theory Cells are the basic units of life. They are the building blocks of all organisms, from bacteria to animals. In 1665, Robert Hooke used a very primitive microscope, to see cells in cork. The Cell Theory was developed from the discoveries of three German scientists: Matthias Schleiden, Theodor Schwann, and Rudolph Virchow. In 1838, Schleiden determined plants were made of cells. In 1839, Schwann discovered all animals were composed of cells. In 1855, Virchow revealed all cells come from existing cells. The modern tenets of the Cell Theory 1. All known living things are made up of cells. 2. The cell is the structural and functional unit of all living things. 3. All cells come from pre-existing cells by division. (Spontaneous Generation does not occur). 4. Cells contain 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 and biochemistry) of life occurs within cells. The three main parts of the Cell Theory All organisms are made up of one or more cells The cell is the fundamental unit of structure and function in living things All cells are essentially the same in chemical composition Types of Cells Cells are classified as either prokaryotic or eukaryotic. Prokaryote Cells have no nucleus or organelles with membranes. Thus, the parts of a prokaryotic cell are Cell wall Cell membrane Ribosome A single chromosome with nucleic acid Bacteria and blue-green bacteria are prokaryotic cells. Eukaryote Cells contain: Nucleus with multiple chromosomes Cell organelles including ribosome and mitochondria Cell membrane. The cells of protozoa, algae, fungi, plants and animals are eukaryotic cells. Grade 10 Applied Science – Biology Pasteur's Experiment to Disprove Spontaneous Growth Nutrient broths were heated and sterilized in a flask with a straight neck and a curved neck. As his control, Pasteur used flasks with straight necks that permitted bacteria to settle into the broth. In these flasks, the broth was soon teaming with bacteria. Pasteur's experimental flasks had long S-shaped necks. With such necks bacteria could not enter, even though they were exposed to air. Therefore no bacteria grew. When the S-shaped neck was removed bacteria began to grow in the sterile media.