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Unformatted text preview: Zhaonan Liu 9/10/07 Lecture 8 The Composition of Cells Cytology - The Biology of the Cell The scale of life Organisms range in mass (size) over 21 orders of magnitude From the smallest microbes that weight <10-13 g (0.1 picogram) to Largest mammals (blue whale) and plants (giant sequoia) that may weigh 10 8 g-All are composed of cells Most cells fall within a fairly narrow size range To survive, cells must exchange molecules with their environment Exchange velocity is directly related to the cell surface area relative to its volume (review & understand Fig 6.7 in text) There are exceptions Caulobacter cescentus Bacterium that inhabits low nutrient, freshwater environments When starved for phosphate, its stalk grows longer to increase its surface area We use this strategy too Intestinal epithelial cells absorb nutrients from the food we eat Microvilli increase surface area Eukaryotic cells are generally larger than prokaryotic cells (bacterial & archaeal cells) Eukaryotic cells have membranebound, subcellular compartments to organize cellular functions Prokaryote Nucleoid (not membrane bound) Generally, these are small, simple looking cells when compared to a eukaryotic cell Bacteria + Archaea Paraphyletic group consists of ancestor and some but not all of its decedents (not nested) vs. Eukaryote Nucleus Complex subcellular structure (membranebound compartments) Microscopy and Biochemistry Microscopy: Study cellular organization and structure or ultrastructure Biochemistry: Fractionate cell parts,study the composition and functions (enzymatic, energetic, structural etc.) Microscopy Basics - light Light microscopy:...
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This note was uploaded on 02/23/2008 for the course BIO G 101 taught by Professor Gilbert,c. during the Fall '07 term at Cornell University (Engineering School).
- Fall '07