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Cells as the Basis of Life - Coggle Diagram

- - - - Prokaryotic organisms do not have membrane bound organelles, i.e. they do not have a nucleus, mitochondria or chloroplasts. The prokaryotic genome is in a circular DNA/protein single chromosome called the nucleoid. Many prokaryotes have fimbriae which are short hair-like structures on the surface that help the prokaryote stick to other cells or to a substrate. Flagella are used by motile bacteria for movement to move either towards or away from stimuli.
    - - A eukaryote has membrane organelles, e.g. nucleus, mitochondria. Eukaryotes include single-celled organisms, e.g. some protista and some fungi and multicellular organisms, e.g. plants, animals, some protists and some fungi.The endomembrane system of eukaryotic cells includes the cell membrane, the nuclear membrane, the endoplasmic reticulum, the Golgi apparatus, lysosomes and other vesicles and vacuoles found within the cell.
  - - - Energy Source
        
        The energy is generated by a light bulb.
      - Focus
        
        Condenser Lens - This lens system is located immediately under the stage and focuses the light on the specimen.
      - Specimen
        Preparation
        
        Place a drop of fluid in the centre of the slide.
        
        Position sample on liquid, using tweezers.
        
        At an angle, place one side of the cover slip against the slide contacting outer edge of the liquid drop.
        
        Lower the cover slowly, avoiding air bubbles.
        
        Remove excess water with the paper towel.
      - Magnification
        
        400-1000 times
      - Resolution
        
        Resolution in an ideal light microscope is limited to around 200 nm
      - Can live specimen be viewed?
        
        yes
      - Image: Colour /
        Black & White
        
        Colour
    - - Energy Source
        
        Electron microscopy uses a beam of electrons as an energy source.
      - Focus
        
        This beam is focused onto the sample using a magnetic lens.
      - Specimen
        Preparation
        
        Samples must be cut into very thin cross-sections. This is to allow electrons to pass right through the sample. After being fixed and dehydrated they are examined.
      - Magnification
        
        Between 1 and 50 million times
      - Resolution
        
        0.05 nm
      - Can live specimen be viewed?
        
        no
      - Image: Colour /
        Black & White
        
        B and W
- - - - Golgi apparatus
      - Ribosomes
      - Cytoplasm
    - - Nucleus
      - Chloroplasts
      - Mitochondria
      - Vacuole
      - Nucleolus
      - Endoplasmic reticulum
      - Lysosome
- - - - Passive movvement of a substance from an area of high solute concentration or low concentration.
    - - Passive movemnet of water to an area of higher concentration
  - - - Phospholipids provide barriers in cellular membranes to protect the cell, and they make barriers for the organelles within those cells.
    - - Peripheral proteins form temporary bonds with the cell membrane, allowing them to detach and reattach at specific times, with specific signals.
    - - A channel protein, a type of transport protein, acts like a pore in the membrane that lets water molecules or small ions through quickly.
    - - Carrier protein is a type of cell membrane protein involved in facilitated diffusion and active transport of substances out of or into the cell.
    - - Cholesterol functions to immobilise the outer surface of the membrane, reducing fluidity. It makes the membrane less permeable to very small water-soluble molecules that would otherwise freely cross. It functions to separate phospholipid tails and so prevent crystallisation of the membrane.
    - - Glycoproteins are found on the surface of the lipid bilayer of cell membranes. Their hydrophilic nature allows them to function in the aqueous environment, where they act in cell-cell recognition and binding of other molecules.
  - - - Endocytosis is a general term describing a process by which cells absorb external material by engulfing it with the cell membrane. Endocytosis is usually subdivided into pinocytosis and phagocytosis.
    - - Exocytosis is the fusion of secretory vesicles with the plasma membrane and results in the discharge of vesicle content into the extracellular space and the incorporation of new proteins and lipids into the plasma membrane.
- - - - The induced-fit model is a model for enzyme–substrate interaction to describe that the substrate is capable of inducing the proper alignment of the active site of the enzyme, causing the latter to subsequently perform its catalytic function.
    - - Lock-and-key model is a model for enzyme-substrate interaction suggesting that the enzyme and the substrate possess specific complementary geometric shapes that fit exactly into one another.