Cell Biology IB SL Biology

2. Cells
1. 3. Common features:
  1. Surrounded by a membrane
  2. Contain genetic material
  3. Cell activity is catalyzed by enzymes produced in the cell
    1. The chemical reactions are known as metabolism
  4. Have their own energy release systems
2. 3. Cell Theory
  1. Living organisms are composed by cells
3. 3. Unicellular Organisms
  1. Prokarytes
    1. Cell structure
      1. Has
        DNA
        In the cytoplasm in the nucleoid
        No proteins
        Cytoplasm
        Holds the DNA
        Cell Wall
        Archaeans don't have cell walls
        Cell wall is outside the cell membrane. Contains peptidoglycan. Extracellular.
        Ribosomes
        In the cytoplasm, makes proteins
        Plasma membrane
        Provides barrier and support for the cell
        Photosynthesis can occur in the plasma membrane
        Cellular respiration occurs in the plasma membrane
        Is a form of metabolism called fermentation
    2. Cell division
      1. Divides by binary fission
        Asexual reproduction
  2. Eukaryotes
    1. Cell structure
      1. Nucleus
      2. Nuclear membrane
      3. Cytoplasm
      4. Ribosomes
      5. Smooth E. R.
      6. Golgi apparatus
      7. Rough E. R.
      8. Micro tubules
      9. Lysosomes
      10. Pila
  3. bacteria, archaea, protozoa, unicellular algae and unicellular fungi.
  4. All the functions of life are carried out in that one cell
    1. 7 functions of life: Nutrition, metabolism, growth, adaptation, excretion, homeostasis, reproduction
4. 3. Multicellular organisms
  1. animals, land plants and filamentous fungi are multicellular, as are many algae
  2. The first evidence of multicellularity is from cyanobacteria-like organisms that lived 3-3.5 billion years ago
  3. Cell differentiation
    1. occurs numerous times during the development of a multicellular organism as the organism changes from a simple zygote to a complex system of tissues and cell types.
    2. Gene Expression
      1. All multicellular organisms in humans have the same set of genes
      2. Cell differentiation happens because a different sequence of gene is expressed in different cell types
    3. Specialization
      1. Specialized tissues can develop by cell differentiation e.g. Red blood cell carries oxygen
        Tissues are a group of specialized cells that perform the same function
  4. Undifferentiated cell
    1. Stem cells
      1. Have the capacity to differentiate(produce different cell types), this is necessary for embryonic development
        Embryonic stem cells can be used to produce regenerated tissue for people with skin burns and other therapeutic uses
        Non-therapeutic: Use large amounts of muscle fibers for human consumption in animals
      2. can divide (through mitosis) to produce more stem cells
5. 3. Microscopes
  1. Electron
    1. Resolution is 1 nanometer
      1. Reveals the ultrastructure of cells
  2. Light
    1. Maximum resolution is 200 nanometers
      1. Reveals the cells structure

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Cell Biology IB SL Biology

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	Created by Elisabeth Morell almost 10 years ago