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24 Cards in this Set
- Front
- Back
Cell Structure
- what are cells? - name the major classes |
* Cells are the structural/functional units of all living organisms
* 3 major classes of biological units: - viruses/prokaryotes/eukaryotes |
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Cell
- general |
* surrounded by a membrane
* divided into compartments which are enclosed with membranes * compartments are called ORGANELLES 2 REGIONS OF CELL: - NUCLEUS contains chromosomes - CYTOPLASM contains organelles and cytosol |
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Membranes
- general |
* SURROUND cell (separate cell from environment
* ENCLOSE organelles (confine chemical reactions within organelle) * REGULATE PASSAGE of materials IN/OUT of cell * ANCHOR cells to adjacent cells * contain RECEPTORS for detection of chemical signals * attachment site for protein filaments (in smooth muscle cells) * all membranes are a DOUBLE LAYER OF PHOSPHOLIPID in which protein is embedded |
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Phospholipid
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* restricts movement of most molecules
* amphipathic hydrophilic portion hydrophobic portion |
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Hydrophilic portion of phospholipid membrane
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* polar/ionized part of molecule
* oriented toward membrane surfaces * attracted to polar water molecules in extracellular fluid and cytosol |
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Hydrophobic portion of phospholipid membrane
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* nonpolar/unionized part of molecule
* oriented with fatty acid chains in middle of double layer |
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Membranes:
Protein |
* serves as pores or channels in membrane
* 2 kinds of membrane proteins: - integral proteins - peripheral proteins * small amount of carbohydrate covalently linked to lipid or protein (monosaccharides/extracellular surface) * fluid-mosaic model |
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Membranes:
Protein - Integral proteins |
* amphipathic (polar amino acid/nonpolar side chains)
* oriented like phospholipids (polar-surface/nonpolar-inner) * transmembrane * some form channels for water/ions * some transmit chemical signals across |
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Membranes:
Protein - Peripheral proteins |
* not amphipathic
* on surface bound to polar region of integral protein * most on cytosol surface * associated with cell shape and motility |
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Plasma membranes of cells intract to form ...
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tissues
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Name the types of
CELL JUNCTIONS |
3 types:
Desmosomes Tight junctions Gap junctions |
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Cell Junctions:
Desmosomes |
* thick glycoprotein at each surface
* fibers extend into cell/across * firm hold from cell to cell * occur where stretch occurs * disc shaped ie: skin, lining of body cavities |
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Cell Junctions:
Tight junctions |
* no extracellular space... membranes join
* form band around cell * restrict molecules ie: epithelial lining of stomach, intestine and nephrons |
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Cell Junctions:
Gap junctions |
* between most cells
* protein channels join cells across gap * small diameter * small molecules/ions pass * proteins held back * transmit electrical signals and chemical messengers ie: cardiac/smooth muscle |
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Organelles:
Nucleus |
* surrounded by nuclear envelope (membrane) / pores
* contains chromosomes (DNA/genetic information) * contains nucleolus (DNA, RNA, protein) * site where ribosomes assembled ... go to cytoplasm |
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Organelles:
Endoplasmic Reticulum (ER) |
* membrane system
* network connects nuclear/plasma membrane granular ER - ribosomes ... protein synthesis agranular ER - no ribosomes ... lipid synthesis (and in the case of muscle cells - Ca++ storage) |
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Organelles:
Ribosomes |
* composed of protein/RNA
* synthesize protein on ER ... Golgi ... protein for export free/chains or clusters ... protein for cell (aka polysomes) |
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Organelles:
Golgi Apparatus |
* membranous sacs
* near nucleus * packages protein synthesized into vesicles |
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Organelles:
Mitochondria |
* rod-like structure
* energy for cell * site of ATP formation * number varies (few/1,000) |
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Organelles:
Lysosomes |
* spherical organelle
* several hundred/cell * sacs of hydrolytic enzymes break down bacteria, debris from dead cells that have been engulfed by cell (phagocytes) |
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Organelles:
Peroxisomes |
* oval sacs
* contain OXIDATIVE ENZYMES which use o2 to remove H in order to detoxify molecules and form H2O2 * also contains CATALASE which catalyzes the conversion of H2O2 to H2O and O2 |
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Organelles:
Microfilaments |
* contractile proteins
* cytoskeleton/ mechanical stress |
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Organelles:
Microtubules |
* hollow tubes
* cytoskeleton, centrosomes, centrioles |
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Organelles:
Cilia |
* hairlike on epithelial cells
* produce movement |