Biology 1201A Chapter Notes - Chapter 2: Collagen, Cytoplasmic Streaming, Centrosome
25 Oct 2012
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In the 1820s, thanks to improvements in microscopes, robert brown noticed a discrete spherical body inside some cells, which he called a nucleus. Theodore schwann proposed that all animals and plants consist of cells that contain a nucleus. Rudolf virchow proposed that cells arise only from pre-existing cells by a process of division. 2. 1 basic features of cell structure and function. Cells carry out the essential processes of life. Contain highly organized systems of molecules, including the nucleic acids dna and rna: carry hereditary information and direct the manufacture of cellular molecules. Use chemical molecules or light as energy sources for their activities. Cells also respond to changes in their external environment by altering their internal reactions. Cells duplicate and pass on their hereditary information as part of cellular reproduction. Life as we know it does not exist in units simpler than individual cells. 2. 1a cells are small and are visualized using a microscope.
