Paper 1: Cell Biology

Paper 1: Cell Biology

1. 2. Cells

   • 3. Common features:
     • Surrounded by a membrane
     • Contain genetic material
     • Cell activity is catalyzed by enzymes produced in the cell
       • The chemical reactions are known as metabolism
     • Have their own energy release systems
   • 3. Cell Theory
     • Living organisms are composed by cells
   • 3. Unicellular Organisms
     • Prokarytes
       • Cell structure
         • 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
       • Cell division
         • Divides by binary fission
           • Asexual reproduction
     • Eukaryotes
       • Cell structure
         • Nucleus
         • Nuclear membrane
         • Cytoplasm
         • Ribosomes
         • Smooth E. R.
         • Golgi apparatus
         • Rough E. R.
         • Micro tubules
         • Lysosomes
         • Pila
     • bacteria, archaea, protozoa, unicellular algae and unicellular fungi.
     • All the functions of life are carried out in that one cell
       • 7 functions of life: Nutrition, metabolism, growth, adaptation, excretion, homeostasis, reproduction
   • 3. Multicellular organisms
     • animals, land plants and filamentous fungi are multicellular, as are many algae
     • The first evidence of multicellularity is from cyanobacteria-like organisms that lived 3-3.5 billion years ago
     • Cell differentiation
       • 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.
       • Gene Expression
         • All multicellular organisms in humans have the same set of genes
         • Cell differentiation happens because a different sequence of gene is expressed in different cell types
       • Specialization
         • 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
     • Undifferentiated cell
       • Stem cells
         • 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
         • can divide (through mitosis) to produce more stem cells
   • 3. Microscopes
     • Electron
       • Resolution is 1 nanometer
         • Reveals the ultrastructure of cells
     • Light
       • Maximum resolution is 200 nanometers
         • Reveals the cells structure