Chapter 2 Study Guide #1

Chapter 2 Study Guide #1 - Chapter 2 10. Animal ^ Organ...

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Chapter 2 10. Animal ^ Organ Systems ^ Organs ^ Tissues ^ Cells ^ Organelles ^ Membranes ^ Macromolecules ^ Simple Molecules ^ Atoms 11. Cells are the functional units of life Perform basic processes 12. Homeostasis: a state of equilibrium in which the internal environment of the body of an animal remains relatively constant with respect to the external environment 13. ? Lack nuclei and other membrane-bound organelles Bacteria Eukaryotic Cell Have cells with a membrane bound nucleus containing DNA Contain organelles that perform specific functions Have a network of specialized structures called microfilaments and microtubules organized into the cytoskeleton, which gives shape to the cell and allows intercellular movement Greatest complexity o Make up the tissue in animals, humans and protista 16. Fluid Mosaic (many different kinds of proteins dispersed in the phospholipid bi layer) Model o The plasma membrane surrounds the cell o A membrane is a double layer (bilayer) of proteins and phospholipids and is fluid rather than solid o Phospholipids form a “fluid sea” and specific proteins float like icebergs
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Being fluid, the membrane is in constant state of flux (shifting and changing) while retaining its uniform structure o Phospholipids have one polar and one non polar end Polar ends are oriented on one side toward the outside of the cell and into the fluid cytoplasm on the other side Non polar ends face each other in the middle of the bilayer The “tails” of both layers of phospholipids molecules attract each other and are repelled by water (because they are hydrophobic “water dreading”) As a result, the polar spherical “heads” are located over the cell surfaces and are “water attracting” (hydrophilic) Cholesterol is present in the plasma membrane and organelle membranes of eukaryotic cells Cholesterol molecules are embedded in the interior of the membrane and help to make the membrane less permeable to water-soluble substances The rigid structure helps stabilize the membrane The membrane proteins are individual molecules attached to the inner or outer membrane surface or embedded in it (intrinsic proteins) Some intrinsic proteins are links to sugar-protein markers on the cell surface Other intrinsic proteins help to move ions or molecules across the membrane, and still other attach the membrane to the cell’s inner scaffolding (the cytoskeleton) or to various molecules outside the cell When carbohydrates unite with proteins, they form glycoproteins and when they united with lipids, they form gylcolipids on the surface of the plasma membrane Surface carbs and proteins of the proteins and lipids make up the glycocalyx (cell coat) o This arrangement of groups of sugar molecules of the gycocalax acts as a molecular “fingerprint” for each cell type o Gycocalax is necessary for cell-to-cell recognition and the behavior of certain cells and it is a key
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Chapter 2 Study Guide #1 - Chapter 2 10. Animal ^ Organ...

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