The Importance of Proteins in the Control of Processes and Responses in Organisms

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  • Created by: Polaris03
  • Created on: 15-05-20 21:54
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  • The Importance of Proteins in the Control of Processes and Response in Organisms
    • Mass Transport
      • Haemoglobin
        • Globular, soluble protein with a quaternary structure.
          • Contains 4 haem groups, each of which can combine with 1 O2 molecule.
          • Important for oxygen transport in mammals as O2 and haemoglobin combine to form oxyhaemoglobin.
      • The quaternary structure of haemoglobin allows it to play its role in the mass transport of oxygen as it follows the oyharmoglobin dissociation curve.
      • Haemoglobin, globular, soluble, quaternary, haem group amd ocyhaemoglobin.
    • Transport Across Cell Membranes
      • Facilitated Diffusion
        • Ions can diffuse through channel proteins in phospholipid bilayer.
          • Channel proteins specific for particular ions.
          • More channel proteins = higher rate of diffusion
          • Can be gated to control rate of diffusion.
        • Large molecules like glucose can only diffuse with carrier proteins.
          • Molecule temporarily binds to carrier protein which changes shape to carry molecule through membrane.
        • Carrier and channel proteins have specific tertiary structures.
      • Active Transport
        • Some carrier proteins use energy from ATP to move ions/ molecules against their concentration gradient.
      • Co-Transport
        • Co-transporter proteins transport 2 substances together across the membrane.
          • Often uses both active transport and facilitated diffusion.
          • E.g. sodium, glucose co-transporters in the epithelial cells of the small intestines.
      • Proteins are essential in transport across cell membranes as proteins are the means by which facilitated diffusop, active transport and co-transport occur.
      • Active transport, facilitated diffusion, co-transport, carrier protein, channel protein, co=transporter, ion, molecule and tertiary.
    • Ribosomes
      • Made up of RNA and protein.
      • Where proteins are synthesised.
      • Ribosomes are made up of RNA and protein and they carry out the function of protein synthesis, which is the way genes are expressed in organisms.
      • tRNA, mRNA, codons, anticodons, translation and synthesis.
    • Enzymes
      • Catalase
        • Catalyses decomposition of hydrogen peroxide.
        • Found in liver.
      • DNA Helicase
        • Breaks hydrogen bonds between bases - allows the 2 strands to separate.
      • DNA Polmerase
        • Attaches new nucleotides to each other, by condensation reactions, forming phosphodiester bonds.
      • RNA Polymerase
        • Links RNA nucleotides together by forming phosphodiester bonds between their ribose and phophate groups.
      • Biological catalysts.
        • Have an active site with a specific structure to one substrate - unique tertiary structure.
      • Enzymes are proteins that catalyse biological reactions, which makes them incredibly important in metabolic functions.
      • Catalyst, active site, ES compound, RNA polymerase, DNA polmerase, catalase and DNA helicase.
    • Structure of Proteins
      • Tertiary
        • Polypeptide chain folds forming complex 3D shapes.
          • Shape determined by where bonds can form = primary sequence.
            • Structure protein-specific.
        • Held together by bonds between R groups.
          • Involves hydrogen and ionic bonding and disulfide bridges.
      • Quaternary
        • Made up of multiple polypeptides.
        • Can contain groups that are not amino acids, e.e. iron ions.
      • Within an organism, there is a range of structures of proteins which are protein-specific, which allows for proteins to perform their specific tasks.
      • Quaternary, tertiary, R groups, polypeptides, hydrogen bonds, ionic bonds and disulfide bridges.
    • Immunology
      • Antigens
        • Cell-specific proteins or glycoproteins that are found on the cell membrane.
          • Immune cells can identify if an antigen is self or foreign, if foreign an immune response is triggered.
            • Allows detection of pathogens, cells from other organisms of same species, abnormal body cells and toxins.
      • Antibodies
        • Proteins which are produced by B lymphocytes.
          • Specific to antigens on foreign cell.
          • Cause agglutination - makes phagocytosis easier.
      • Phagocytosis
        • White blood cells (e.g. macrophages and neutrophils) can take in bacteria via phagocytosis.
          • Extend psudopodia around bacteria creating phagosome.
            • Lysosome fuses with phagosome and injects lysozymes into phagosome.
              • Destorys bacterial cell walls - hydrolyses murein.
      • T-Helper Cells
        • Release cytokines (small proteins) which stimulate killer T cells, B lymphocytes and phagocytes to respond to infection.
      • Within the immune system, there is a range of proteins that respond the infection of the organism with cells that have foreign antibodies.
      • T-helper cells, antibodies, B lymphocytes, antigens, phagocytosis, cytokines and agglutination.

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