Cell Shape and Size, Subcellular Structures

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Cell Shape and Size, Subcellular Structures
2012-10-20 13:06:41

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  1. Most cells are between __ in diameter and are visible only under microscope.
    1 and 100 μm
  2. Genetic control of the cell: __
  3. The nucleus houses __, directs __ by __ from __, which is then transported ot the __ via __ and turns into a __.
    • most of the cell's DNA
    • protein synthesis
    • mRNA
    • cytoplasm
    • nuclear pores
    • polypeptide
  4. Nucleus:
    1.     Contains most of the __

    a. Complex of DNA and proteins making
    up chromosomes is __

    b. Characteristic __of

    i.     Humans: __/ sex cells: __
    • genes in chromosomes (one long DNA molecule)
    • chromatin
    • number
    • 46
    • 23
  5. Nucleus

     1.      Enclosed by __, which does what?
    a.      It is a __, each a lipid bilayer with proteins and separetaed by __
    b.      Perforated by __that are continuous with __
                                                                                                                                          i.      Explain pore complex?
    c.       Nuclear side of envelope lined by __, a netlike array of protein filaments that does what? 
                                                                                                                                          i.      This and nuclear matrix may help __.
    • nuclear envelope
    • separates it from contents of cytoplasm
    • Double membrane
    • space
    • pores
    • ER
    • lines each pore and plays role in regulating entry and exit of proteins and RNAs and macromolecules
    • nuclear lamina
    • maintains the shape of the nucleus by mechanically supporting the nuclear envelope
    • organize genetic material
  6. 1.      __forms __by instructions of DNA
    a.      Proteins imported from the cytoplasm are assembled with rRNA into large and small subunits of ribosomesà exit nucleus through pores
    • Nucleolus
    • rRna
  7. __, which use information from the DNA to make proteins

    Made of __; carry out __
    • ribosomes
    • ribosomal RNA and protein
    • protein synthesis
  8. Ribosomes build protein in two cytoplasmic areas
    • a. Free: in cytosol
    •    ----- Proteins made funcition within cytosol
    • b. Bound: attached to outside of ER or nuclear envelope
    •    ------ Make proteins destined for insertion into membranes, for packaging within certain organelles, or for export from the cell
    • c. Both identical and can alternate between roles
  9. Endomembrane System carries out variety of tasks, such as __, __, __, and __. They do not have identical membranes
    • protein synthesis
    • transport into membranes and organelles or out of cell
    • metabolism and movement of lipids 
    • and detox of poisons
  10. What are the structures of the endomembrane system?
    • nuclear envelope
    • ER
    • Golgi apparatus
    • lysosome
    • vacuole
    • vesicles
    • plasma membrane
  11. ER:
    1. More than half the__ in eukaryotic cells
    2. Consists of membranous tubules and sacs called __
    3. Speratares the __ from the __
    •  total membrane
    • cisternae
    • internal compartment of the ER, called the ER lumen (cavity) or cisternal space
    • cytosol
    • 1) lacks ribosomes
    • 2) synthesizes lipids (oils, phospholipids, sex hormones and steroids)
    • 3) metabolizes carbs
    • 4) detox of drugs and poisons
    • 5) stores Ca ions
  13. Explain how the SER detoxifies drugs adn poisons?
    • Involves adding –OH groups to make
    • drugs more soluble

    • Drugs induce proliferation of
    • smooth ER, thus increasing the rate of detox , which increases tolerance, and
    • more doses are required to achieve desired result
  14. Explain how the SER stores calcium ions?
    • i. Pumps calcium ions from the cytosol to the ER lumen
    • --1. Calcium ions rush iinto cytosol when stimulated by nerve cell to cause movement
  15. Rough ER
    • 1) studded with ribosomes on outer surface
    • 2) growth of polypeptide chain occurs through bound ribosomes and threaded into ER lumen through pore formed by protein complex
    • --- most secretory proteiins are glycoproteins
    • 3) after formed, they are separated from free proteins adn depart from transitional ER
    • 4) membrane factory
  16. Explain rough ER's function as membrane factory?
    • i. Grows in place by adding membrane proteins and phospholipids to its own membrane
    • 1. Anchored by hydrophobic portions
    • ii. Makes phospholipids
    • iii. Vesicles tranferr its items
  17. Golgi Apparatus
    1) Products of ER are __ and __ and set to other destinations.
       a) __ are modified.
    2) Consists of flattened membranes called __.
       a) The membrane of each separates its internal space from cytosol
    3) Manufactures __.
    4) Beofre products depart, they are __ and __ to various parts. 
       a) __ aid in sorting
       b) Transport vesicles from the Golgi may have external  molecules on membranes that recognize __ on the surface of specific organelles or on the plasma membrane
    • modified and stored
    • glycoproteins' carbohydrates
    • cisternae
    • some macromolecules
    • sorted and targeted
    • molecular ID
    • docking stations
  18. Explain the membranes of cisternae on golgi.
    • b. Membranes of cisternae on opposite sides of a stack differ in thickness and molecular composition; products are modified during transit from cis region to trans region
    • i. Cis face: located near ER
    • 1. a vesicle that buds from the ER can add its membrane and contents of its lumen to the cis face through fusion
    • 2. trans face
    • a. gives rise to vesicles that pinch off
  19. Explain the golgis funciton of manufacturing macromolecules.
    • a.      Like secretory proteins, nonprotein Golgi products depart from trans face and fuse with plasma membrane
    • b.      Manufactures in stages
    •                                                                                                                                       i.      Cisternal maturation model: cisternae of the Golgi progress forward from cis to trans face, carrying and modifying their cargo as their move
  20.                                                               i.      Lysosomes
    1.      __environments
    a.      excess leakage can __ cell due to __
    2.      __ and __ are made by __and transferred to __for further processing
    3.      some Lysosomes arise by __
    4.      3D shapes of proteins in Lysosomes protect __
    5.      __ digestion

    6.       Engage in autophagy, which is __? 
    • acidic
    • destroy
    • pH
    • hydrolytic enzymes
    • lysosomal membrane
    • rough ER
    • Golgi
    • budding from trans face
    • vulnerable bonds from enzymatic attack
    • Intracellular
    • Use their hydrolytic enzymes to recycle the cell’s own organic material
  21. Explain lysosome's function of phagocytosis?
    • engulfing
    • i. Forms food vacuole, which fuses with lysosome, whose enzymes digest the food
    • ii. Macrophages also do this
  22. Explain lysosome's function of autophagy?
    • a. Damaged organelle or small amount of cytosol becomes surrounded by double membrane and lysosome fuses with outer membrane of this vesicle
    • i. Enzymes dismantle the enclosed material, and make it available to the cytosol
  23. Lysosomes:
    __ can be caused by lack of functioning hydrolytic enzymes, causing them to become engorged with __, which interfere with __.
    • Diseases
    • indigestible substrates
    • other cellular activities. 
  24. Vesicles
    transfer membrane segments
  25. Vacuoles
    1. Derived from __ and __ 
    2. Selective in __, which causes what? 
    3. Types
    4. Some carry out __.
    • ER/ Golgi apparatus
    • transporting solutes
    • solution inside differs in composition from cytosol
    • Food and contractile
    • enzymatic hydrolysis
  26. Explain contractile vacuoles.
    Pump excess water out of the cell, thereby maintaining a suitable concentration of ions and molecules inside the cell
  27. Explain small vacuoles in plants. 
    • smaller vacuoles can hold reserves of important organic compounds.
    • a) They can protect plant form herbivores by storing compounds that are poisonous or unpalatable to animals and contain pigments
  28. Explain central vacuole in plants.
    • a. Solution inside (cell sap) is plant cell’s main repository of inorganic ions
    • b. Growth of plant cells, which enlarge as the vacuole absorbs water