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2014-01-20 02:22:44
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  1. What is cytosol? What is it made of?
    • Fluid portion of the cytoplasm that makes up about 55% of cell volume, many chemical reactions required by the cell happen in the cytosol
    • 75-90% of cytosol is water with the rest dissolved and suspended materials that include:
    • Ions
    • glucose
    • amino acids
    • ATP
    • Proteins
    • Lipids
    • Fatty acids
    • Waste products
  2. What is the cytoskeleton? What is it made of?
    • A network of protein filaments that extend throughout a cell.
    • Made of three different types of filaments named (increasing in diameter) microfilaments, intermediate filaments, and microtubules.
  3. What are microfilaments? What are they made of and where do they reside?
    • micro= small, filament= threads
    • Thinnest components of the cytoskeleton that are most prevalent at the edge of cells
    • Made of myosin and actin
  4. What are the two general functions of microfilaments?
    • Provide mechanical support help generate movement.
    • Movement: Muscle contractions, cellular devision, cellular locomotion 
    • Mechanical support: Responsible for basic strength and shape of cell, anchor cytoskeleton to integral proteins in the PM, provide cellular support for microvilli.
  5. What are microvilli?
    • micro= small, villi= tufts of hair
    • singular= microvillus
    • Nonmotile (cannot move) finger like projections of a cells PM that have parallel sections of microvilli that support it.
    • Greatly increase surface area of cells, can be found abundantly on involved with absorption such as epithelial cells that line small intestine.
  6. What are intermediate filaments? What is it made of?
    • MF<IF<MT, can be composed of several different proteins
    • Exceptionally strong and found in parts of cell subject to mechanical stress.
    • Help stabilize organelles such as nucleus, and help attach cells to one another.
  7. What are microtubules? Where do they form? What are their functions?
    • Largest part of the cytoskeleton, large unbranched hollow tubes make primarily of tubulin.
    • Microtubules begins assembly in centrosomes (organelles) and grow towards periphery of cell.
    • Function in the movement of organelles (secretory vesicles), chromosomes during cellular devision, and specialized cellular projections (cilia and flagella).
  8. What are organelles?
    • Specialized structures in cells that have characteristic structures, preform specific functions in cellular reproduction, growth, and maintenance.
    • Types and number of organelles differer between different types of cells depending on their function.
    • Organelles have different functions but cooperate to maintain homeostasis.
  9. What allows chemical reactions in cells to happen undisturbed.
    Different organelles have their own enzymes and function as compartments that allow reactions and biochemical processes to happen without interference.
  10. What is a centrosome?
    • Located near nucleus and consists of two components: 
    • Centrioles and pericentriolar material
    • Centrosomes replicate during cellular devision so succeeding generations can divide as well.
  11. What are centrioles and pericentriolar material? (components of centrosomes)
    • Centrioles- Two cylindrical structures each made of nine groups of three microtubules, in a circular pattern, that run perpendicular to each other.
    • Pericentriolar material- Hundreds of ring shaped complexes composed of the protein tubulin, organizing center for growth of mitotic spindle (plays critical role in cellular devision) and microtubule composition in nondividing cells
  12. What are cilia and flagella?
    • Motile projections of a cells PM
    • Dominant components are microtubules
  13. What are the functions and anatomy of cilia?
    • cilia= eyelashes, singular= cilium 
    • Numerous, short, hair like projections that extend from surface of cell.
    • Each cilium contains 20 microtubules, nine groups of two in a circular ring and a group of two in the middle. Each cilium is anchored to a basal body (similar to centrioles) just below surface of PM that is used to initiate assembly of cilia and flagella.
    • Coordinated movement of many cilia causes steady movement of fluids on the cells surface.
  14. What is a basal body?
    Similar to structure in centrioles ( nine (tri)tubulin proteins) and initiates assembly of flagella and cilia.
  15. What are the functions and anatomy of flagella?
    • flagella= whip, singular flagellum
    • Similar in structure to cilia but much longer
    • Used for cellular movement by creating wave-like motion
    • Only found in sperm cells in humans
  16. What are ribosomes?
    • ribo= ribosomal RNA (rRNA), somes= bodies
    • Sites of protein synthesis in cells
    • Named after their high content of ribosomal RNA but each contain over 50 TYPES of proteins
    • Made of two subunits, one half the size of the other, made separately in the nucleolus and joined in the cytoplasm
    • Can be attached to the outer surface of PM or organelles (make proteins for those structures or for other cells), or float freely in the cytosol (make proteins used in the cytosol)
  17. What is the endoplasmic reticulum?
    plasmic- cytoplasm, reticulum- network