Cells Chapter 2 mindmap

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  • Created on: 02-02-17 13:57
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  • Cells Chapter 2
    • Cell Structure
      • Studying cells
        • Microscopy
          • Electron microscope are either scanning or transmission. TEMs use electromagnetis to focus a bean of electrons, which is then transmitted through the specimen. SEMs scan a bean of electrons across the specimen.
          • Light microscope they uses light to from an image. you can view organelle such as ribosomes, the endoplasmic reticulum and lysosomes.
          • Magnification and resolution- magnification= size of image / size of real object x100
          • Cell fractionation- 1 ) Homogenisation - breaking up the cells 2) Filtration- getting rid of the big bits 3) Ultracentrifugation- separating the organelles
      • Eukaryotic cells
        • Organlelles- Nucleus, mitochondria, chloroplast, golgi apparatus, golgi vessicles, lysosomes, ribosomes, rought endoplasmic reticulum, smooth endoplasmic reticulum, cell wall cell vacuole.
      • Prokaryotic cells
        • No membrane bound organelles. Also has a capsulemade up of secreted slime. Has plasmids and circular DNA. DNA not attached to histones. Flagellun that rotaes to make theprokaryote move.
        • Replicate by binary fission
        • Viruses are not cells because they are not alive they don not under go cell division so they inject their DNA or RNA into the host cell
      • Cells specialise
        • Tissue cell- Tissue - organ- organ system
      • New cells
        • cell cycle- consists of periods of cell growth and DNA replication called interphase. Mitosis happens after that . Interphase is subdivided into 3 separate growth stages these are called G1,S and G2
        • Nuclear division
          • Mitosis-              1) Interphase 2) Prophase 3) Metaphase 4) Anaphase 5) Telophase
          • Cytokinesis When the cytoplasm splits
            • Cancer - is the result of uncontrolled cell division.
    • Cell recognition and the immune system
      • Foreign antigens trigger an immune response         1) phagocytes engulf pathogens        2)phagocytes activate T-cells                 3) T-cells activate B-cells, which divide into plasma cells  4) plasma cells make more antibodies to a specific antigen
      • Cellular response- The T-cells and other immune system cells that they interact with, e.g. phagocytes.     Humoral response- B-cells, clonal selection and the production of mono clonal antibodies.
      • Phagocytes
        • A phagosyte recognises the foreign antigen on a pathogen. the cytoplasm of the phagocyte moves round the pathogen, engulfing it. the pathogen is now contained in the phagocyte vacuole in the cytoplasm of the phagocyte. A lysosomes fuses with the phagocytic vacuole. the lysozymes break down the pathogen. the phagocyte then presents the pathogen's antigens.
      • Immunity
        • Active Immunity- when your immune system make sits own antibodies after being stimulated by an antigen.
        • Passive immunity- from being given antibodies made by a different organism- your immune system doesn't produce any antibodies of it own.
        • HIV- Is the virus that causes AIDS. HIV has a spherical structure and replicates inside its host's helper T-cells.
          • HIV infects helper T-cells. whithout enought T-cells the immune system is unable to mount an effective rsponce to infections.
    • Transport across cell membranes
      • Diffusion- The net movement of particles down a concentration gradient from an area of higher concentration to an area of lower concentration.
      • Facilitated diffusion- Some molecules cannot fit through the phospholipid bi layers. instead they can travel through carrier proteins located along the membrane.
      • Osmosis- Is the diffusion of water molecules across a partially permeable membrane from an area of higher water potential to an area of lower water potential.
      • Active transport- uses energy to move molecules and ions across membranes, usually against a concentration gradient.
      • Glucose absorbed in the ileum- in the ileum the concentration of glucose is too low for glucose to diffuse out into the blood. So glucose id absorbed from the Lumen of the ileum by co- transport.
      • Structure of the cell surface membrane-   Surrounded  cells. They are a barrier between the cell and its environment, controlling which substances enter and leave the cell. They're partially permeable.
        • Fluid Mosaic model-  Describes the arrangement of molecules in the membrane. IN the model phospholipid molecules from a continuous, double layer. this bi layer is fluid because the phospholipids are constantly moving.


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