Ch 4

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Ch 4
2010-10-13 19:11:18

The cell
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  1. Cell
    • Are the basic unit of structure and function in organisms
    • all living things are composed of one or more cells
    • all cell come only from other cells
  2. Prokaryotic cells
    • Bacteria or archaea(another microspic life form)
    • do not have a nucleus
    • single - celled organisms
    • DNA is coiled into a "nucleoid" region that is not separated from the rest of the cell by a membrane
    • one type of organell
    • muche smaller, than eukaryote
  3. Eukaryotic cell
    • All plants, animals(humans), fungi
    • membrane-bound nucleus
    • multicellular
  4. Organells
    highly organized structures inside teh cells that serve a specialized function
  5. Why are cells so small?
    • They need a lot of surface area to export and import materials throught the plasma membrane
    • Small cells have a greater surface area to volume ration than large cells
    • As a cell grows bigger, its volume increases more rapidly than its surface area
  6. Cytosol
    fluid in which organells are immearged
  7. Cytoskeleton
    • a network of protein filaments that function in:
    • cell structure
    • cell movement
    • transport of materials
    • Helps cell to maintain their shape
    • dismantle and reform
    • Three types:
    • 1. Microfilaments
    • 2. Intermediate Filaments
    • 3. Microtubules
  8. Microfilaments
    • Changes in cell shape
    • Provide structural support
    • Help cell move or capture prey
  9. Intermediate filaments
    • Maintenance of cell shape
    • Stabilize the position of the mucleus and other organelles
    • Are the most permanent element of the cytoskeleton
  10. Microtubules
    • Maintenance of cell shape, movement of organelles, cell mobility(cilia and flagella)
    • Act as track to trasport vesicles
    • guide the movement of chromosomes when cell divide
    • form the underlying structure for two kinds of cell extensions, cilia and flagella
  11. Cytoplasm
    region of the cell inside the plasma membrane but outside the nucleus
  12. Nucleus
    • Contains a cell's DNA
    • The site where new DNA is synthesized
    • is lined bya double membrane called nuclear envelope
    • Nuclear pores: microscopic channels
  13. Protein production
    • Instructions from DNA are copied onto mRNA
    • mRNA moves to free-stending ribosome
    • Ribosome reads mRNA instructions and start to build a chain of amino acids
    • Ribosomes migrate to rough ER and dock, and amino acid chain enters the ER
    • Inside the ER, amino acid chain folds up and becomes a protein
    • Proteins are trasported from the rough ER to Golgi complex for additional processing and for sorting.
    • At golgi complex, a network of membranes that processes and distributes proteins (it edits, sorts, packages, and ships proteins)
    • Transport vesicles bud off from the golgi complex and transported out of the cell.
  14. Nuclear pores
    through which things exit the nucleus to cytoplasm
  15. Ribosomes's function
    • organell that serves as the site of protein synthesis in the cell. Ribosomes make a little chain of amino acid and stop becuase there will be a signal saying that "ER processing needed" and it will go to ER to complete the process of making a protein.
    • Some ribosomes will ramain free-standing and make proteins that will be used in the cell's cytoplasm or nucleus.
  16. Ribosomes structure
    • are made of mixture of proteins and ribosomal RNA (rRNA)
    • rRNA is produced in the nucleolus
    • Only type of organell that is not lined by a membrane
    • Only type of organell present in prokaryotic cells
  17. Rough ER
    a network of membranes that aid in the processing of proteins in eukaryotic cells.
  18. Nucleolus
    the area within the nucleus of a cell devoted to the production of ribosomal RNA
  19. Transport vesicles
    • the membrane lined sphere that move whithin this network, carryiing proteins and other molecules.
    • These vesicles are propelled along the cytoskeleton.
  20. Endomembrane system
    an interactive group of membrane-lined organelles and trasport vesicles whinin eukaryotic cells. A unique property of a membrane to bud off from one organell and fuse with another releasing its content.
  21. Golgi Complex
    • is a network of membranes that processes and distributes protein that come to it from the rough ER.
    • Act as a distirbution center, putting chemical tags.
  22. Smooth ER
    • Lacks the ribosomes that cover rough ER
    • Does not participate in protein synthesis
    • Synthesizes lipids (fats) by the cells of liver and fat cells. (steroids) by cell of ovaries and testes.
    • Detoxifies harmful substances mostly in the liver cells.
  23. Lysosome
    • Organelles that digest worn out cellular materials and foreign materials
    • Fuse with the membrane of a worn-out organelle and engulf it
    • Filled with numerous enzymes that break down large molecules.
    • Return smaller usable molecules back to the cytosol
  24. Mitochondria
    • The "powerhouses" of cells
    • Extract energy from food and convert it into ATP
    • ATP energy is used to power cellular functions
  25. Cilia
    hair like growths that move back and forth rapidly to move a cell to move material around a cell
  26. Flagellum
    long tail like extensions that function in cell movement
  27. Central Vacuole
    • Composed mostly of water
    • Contains many other substances:
    • Nutrients
    • Waste products
    • Hydrogen ions - to keep cell's cytoplasm at a near neutral pH.
    • Digestive enzymes
  28. Cell wall
    • Outer protective lining
    • Helps cells maintain their shape
    • Prevents cells from absorbing too much water
    • Composed primarliy of cellolose, a polysaccharide
    • Animal cell never have cell walls.
  29. Chloroplasts
    • Organelles where photosynthesisi takes place
    • Only pant and algae cells have them
  30. Interactions between plant cells
    • Most plant cells are linked together into tissues
    • PLasmadesmata, tiny pores between cells, allow for the movement of materials ( cytoplasm of one cell continious with the other)
    • Permanent open chennel between cells.
  31. Interactions between animal cells
    • Gap junction: clusters of protein strucutres that span tha plasma mabrane of a cell
    • Tubes of adjacent cells line up and allow for the passage of molecules and electrical signals.
    • Open only as necessary.