Cells Pp Part 1


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Cells Pp Part 1

  1. 1. Today’s Objectives:<br /><ul><li>The Origin of Life
  2. 2. Conditions for the Origin of Life
  3. 3. Cells</li></li></ul><li>Origin of Life<br />The evolution of the Earth has involved the following sequence of events<br />Unicellular or single celled organisms<br />Multi-cellular organisms<br />Increase in cell number<br />Cell specialization<br />
  4. 4. Conditions for the Origin of Life<br />A sequence of chemical reactions lead to life on Earth<br />Sun and planets coalesced as result of a supernova<br />On Earth, heavier materials sank to the core while lighter substances concentrated the surface<br />Hydrogen, Oxygenand Carbon<br />
  5. 5. Conditions (Cont.)<br />Current Atmosphere:<br />78% N2<br />21% O2<br />Trace amounts of CO2,<br />Primordial Atmosphere:<br />Far more Hydrogen<br />Far less Oxygen<br />NH3, H2O, and CH4<br />
  6. 6. CHON<br />4 common elements in living organisms<br />Carbone, Hydrogen, Oxygen, and Nitrogen<br />Some include 2 others Phosphorus and Sulfur<br />P is crucial in DNA/RNA ; forms core of the phosphate groups in ATP/ADP<br />S is used in the formation of some amino acids<br />
  7. 7. Conditions (Cont.)<br />Ocean Formation:<br />High temperatures of Earth’s early crust continually evaporated water that had rained<br />As the Earth cooled, rain water washed dissolved minerals to low areas creating lakes, seas, and oceans<br />Volcanic explosions on land and in our oceans were the cause for accumulation of salts in our oceans<br />
  8. 8. Stanley Miller Experiment<br />Miller duplicated chemical conditions of early oceans and atmosphere and provided an energy source (electric spark)<br />Found that the warm water and gasses when provided an energy source would continue to spark for about a week, forming organic compounds.<br />Further experimentation supports Miller’s evidence by stating that amino acid that make up proteins form quite readily in this environment. <br />
  9. 9. Cells<br />Magnification needed to be seen<br />Termed by Robert Hooke in 1665<br />Observed cork under magnification <br />Cell<br />Functional basic unit of life<br />Hooke’s initial discovery led to differentiation in plant and animal cells<br />Plant cells have a thick cell wall<br />Animal cells have a thinner, more flexible plasma (cell) membrane<br />
  10. 10. Cells<br />Unicellular organisms<br />carry out all necessary functions that support life within one cell without any help from other cells<br />Multi-cellular organisms<br />An organism consisting of many cells<br />Cells have specific functions, and the aggregate of cells forms a complex organism<br />
  11. 11. Cell Theory<br />Termed by Matthias Shleiden and Theodor Schwann<br />Cell Theory states:<br />Cells are the fundamental units of life<br />Cells are the smallest entities that can be called living<br />All organisms are made up of one or more cells and new cells arise from pre-existing cells.<br />
  12. 12. Cell Structure and Size<br />Cells provide structure and form to the body by coming in a variety of shapes and sizes<br />e.g., round, concave, rectangular, elongate, tapered, spherical, etc.<br />Range from 5 – 50 microns<br />Short for micrometer (10-3)<br />
  13. 13. Cell Structure and Size<br />Cell size:<br />Restriction by ratio of surface area to volume<br />Cells have a relationship with their surrounding medium and constantly absorb and release molecules.<br />Cell volume increases much more rapidly in perspective with the surface area and cell may become too large to maintain a stable internal environment<br />
  14. 14. Cytoplasm & Nucleoplasm<br />Cytoplasm<br />Everything within the plasma membrane except the nucleus <br />Nucleoplasm<br />Contents within the nuclear membrane<br />
  15. 15. Cell Membrane<br />Cell Membrane:<br />Membrane surrounding the cytoplasm at the surface of the cell<br />Contains various amounts of proteins and lipids<br />Provides support, shape, strength, and regulates flow of materials<br />Fluid-mosaic model<br />Explains how molecules can move in and out of cell<br />
  16. 16. Movement Thru Membrane<br />Cells use 2 methods to keep a Chemical homeostasis or maintaining a constant internal environment.<br />Passive transport<br />Molecule movement occurs on its own without any energy input<br />Active transport<br />Cell expends energy to move molecules<br />
  17. 17. Questions to think about<br />There are 4 elements common to living things. Name them.<br />What is a cell? How do plant and animal cells differ?<br />What is the cell theory?<br />What is a plasma (cell) membrane?<br />
  18. 18. Exit Ticket<br />Why are most cells small?<br />