NATS 1610 Lecture Notes - Lecture 6: Microtubule, Chromatin, Phospholipid
1 Oct 2015
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Document Summary
Cells vary in size & shape, but are still small. (for example frog egg 1mm) The discovery of cells followed the invention of the microscope . 3 common microscopes were used for viewing cells: compound light microscope, scanning electron microscope, transmission electron microscope. The metabolic requirements set an upper limit to the size of a single cell. As cell increase in size its volume increase faster than its surface area(smaller objects have a greater ratio of surface area to volume) The sa of cell is its cell membrane (want to have more cell membranes for efficient waste diffusion) Cell divide instead of growing larger to limit their surface area to volume ratios . Cell gets around this problem by : dividing (sa increases v=const, getting thinner (sa increase v=const, forming microvilli (extra membrane creates more sa, storing nutriens. Types of cells: procaryotic dna is not enclosed in nucleus, eucaryotic-dna is enclosed in a nucleus ,cytoplasm is filled with organelles.
