Cells part 1

  1. cell theory
    1st unifying theory of biology

    • Cells are the fundamental units of life.
    • All organisms are composed of cells.
    • All cells come from preexisting cells.
  2. Why are cells so small?
    • A small diameter allows for a high surface area-to-volume ratio. (which is essential)
    • Volume determines the amount of chemical activity in the cell per unit time.
    • Surface area determines the amount of substances that can pass the cell boundary per unit time.

    (page 4 on slide)
  3. The __ is the outer surface of every cell, & has more or less the same structure in all cells.
    plasma membrane
  4. functions of the plasma membrane
    • selectively permeable barrier
    • allows cells to maintain a constant internal environment
    • is important in communication & receiving signals
    • often has proteins for binding & adhering to adjacent cells
  5. The plasma membrane is made up of a __ bilayer with __ & other molecules embedded.
    phospholipid; proteins

    It is not rigid, but more like an oily fluid in which the proteins & lipids are in constant motion.
  6. proteins in the the plasma membrane
    • glycoprotein (has carb side chain)
    • integral protein
    • transmembrane protein (goes through the bilayer)

    (page 11 on slide)
  7. 2 types of cells
    • prokaryotic cell: in bacteria & archaea, DNA is contained in the nucleoid
    • eukaryotic cell: DNA is in a membrane-enclosed nucleus

    (page 12 on slide)
  8. found in both cells of prokaryotes & eukaryotes
    • ribosomes (float freely in prokaryotic cells)
    • plasma membrane
    • cytoplasm
    • DNA

    (page 12 on slide)
  9. Cytoplasm consists of __ (water & dissolved material) & suspended particles.
  10. ribosomes
    sites of protein synthesis
  11. nucleus
    • usually the largest organelle
    • contains the DNA
    • site of DNA replication
    • site where gene transcription is turned on & off
  12. nucleolus
    • center of nucleus
    • where assembly of ribosomes begin
  13. The nucleus is surrounded by 2 membranes - the __
    nuclear envelope

    (page 16 on page)
  14. function of nuclear pores
    control movement of molecules between nucleus & cytoplasm
  15. Some large molecules (e.g., proteins) must have a certain amino acid sequence known as a __ to cross the nuclear envelope.
    nuclear localization signal (NLS)
  16. The endomembrane system includes the __
    • plasma membrane
    • nuclear envelope
    • endoplasmic reticulum
    • golgi apparatus
    • lysosomes
  17. network of interconnected membranes in the cytoplasm
    endoplasmic reticulum
  18. function of rough endoplasmic reticulum (RER)
    synthesis of new proteins

    New synthesized proteins are transported into the RER lumen, modifies, folds, & transports the proteins
  19. function of smooth endoplasmic reticulum (SER)
    synthesis of lipids, oils, phospholipids, steroids
  20. ribosomes
    • consist of more than 50 different protein molecules
    • noncovalently bonded to ribosomal RNA
    • considered little factories for proteins
    • not considered an organelle
  21. Where can ribosomes be found in eukaryotic cells?
    • free in cytoplasm or attached to the ER
    • inside mitochondria & chloroplasts
    • in neurons found over a meter from the cell body
  22. The golgi apparatus is composed of __
    • flattened sacs (cisternae)
    • small membrane-enclosed vescicles
  23. functions of the golgi apparatus
    • receives proteins from the RER - can further modify them
    • concentrates, packages, sorts proteins
    • adds & modifies carbs to proteins
  24. The __ region of the golgi apparatus receives vesicles form the ER.
  25. At the __ region, vescicles bud off from the golgi apparatus & are moves to the plasma membrane or other organelles.
Card Set
Cells part 1
Week 1, Ch. 5