Cells EXAM 2

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  1. cells
    • reproduce via DNA
    • grow and develop
    • take energy from environment
    • sense and respond to environment (plant towards sun) 
    • maintain constant internal conditions (homeostasis)
    • evolve over time
  2. cells are the
    smallest units of life
  3. why are cells so small?
    • cell needs a surface area large enough
    • to allow for adequate nutrients to enter and to rid its wastes

    • Small cells are likey
    • to have any adequate surface area
  4. cell theory
    • Originated from the work of Schleiden
    • and Schwann in 1838-9 


    • 1.All living organisms are composed of one
    • or more cells

    2.Cells are the smallest units of life

    • 3.New cells come only from pre-existing
    • cells by cell division
  5. Microscopy
    • Magnification
    • Resolution
    • Contrast
  6. Magnification
    Ratio between the size of an image produced by a microscope and its actual size
  7. Resolution
    • ¨Ability to observe two adjacent objects
    • as distinct from one another
  8. Contrast
    • ¨How different one structure looks from
    • another – enhanced by dyes
  9. light vs electron microscope
    • one uses light another uses electron beam
    • electron has more resolution
  10. types of electron microscope

    *both coated with heavy metal
    • transmission - some
    • electrons are scattered while others pass through to form an image

    • scanning -  Beam
    • scans surface to make 3D image

    both no live speciment
  11. prokaryotic cell
    • Simple cell structure
    • Lack a membrane-enclosed nucleus

    2 categories- bacteria and archaea
  12. Bacterial cell
    • Plasma membrane
    • Cytoplasm
    • membrane
    • Nucleoid
    • Ribosomes
  13. External features of prokaryotes
    • Cellwall
    • Glycocalyx-traps water, protection
    • Capsule - may help evade immune system
    • Appendages- pilli flagella (locomotion)
  14. Eukaryotic cell
    • nucleus
    • exhibit compartmentalization via organelles
    • Shape, size, and organization of cells vary considerably among different species and
    • even among different cell types of the same species
  15. Why compartmentalize
    • isolate reactions - each part has it's own job
    • more surface area
  16. 2 parts
    endomembrane system -- organelles that communicate with one another via membrane channels and small vesicles

    • Energy related organelles - Mitochondria & chloroplasts (energy independent &
    • self-sufficient)
Card Set:
Cells EXAM 2
2013-10-26 19:43:15
Biology Exam cellbs

Biology exam 2
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