WEEK 1

    Cards (444)

    • What do cells and organelles need to do with molecules?
      Take up and release molecules
    • What is required for cells to take up or release molecules?
      Membrane proteins are required
    • What is the structure of the cell membrane?
      Phospholipid bilayer
    • What does it mean that the cell membrane is selectively permeable?
      It allows certain substances to pass
    • What does the plasma membrane separate?
      Intracellular contents from extracellular environment
    • What is the role of intracellular membranes?
      They separate organelle contents from the cell
    • What happens without membranes in cells?
      No concentration gradients, no energy
    • How does simple diffusion differ from transporter-mediated diffusion?
      Simple diffusion is non-saturable, linear kinetics
    • What percentage of the human genome codes for membrane proteins?
      Approximately 20%
    • What percentage of drug targets are membrane proteins?
      60%
    • What are the typical protein and lipid compositions of different cell membranes?
      • Typical cell plasma membrane: 50% protein, 50% lipid
      • Mitochondrial inner membrane: 75% protein, 25% lipid
      • Myelin sheath: 25% protein, 75% lipid
    • What is the significance of membrane proteins in selective permeability?
      They act as gateways for solutes
    • What are the two types of domains in membrane proteins?
      Hydrophilic and hydrophobic domains
    • How do hydrophilic domains interact with the environment?
      They interact with the aqueous environment
    • How do hydrophobic domains interact with the phospholipid bilayer?
      They interact with the non-aqueous core
    • What structure do most eukaryotic integral membrane proteins form?
      Alpha-helices
    • What is the hydropathy index of an amino acid?
      A number representing hydrophobic properties
    • What are the types of transmembrane proteins?
      1. Single pass α-helix
      2. Multiple pass α-helix
      3. Rolled up β-sheet (β-barrel)
      4. Anchored by amphiphilic alpha helix
      5. Via lipid anchors
      6. Membrane-associated proteins
    • How do membrane proteins interact with the membrane?
      Through various non-covalent interactions
    • What is the role of glycosylation in extracellular domains?
      It provides protective carbohydrate layers
    • What are the functions of the carbohydrate layer on cells?
      1. Protects from extracellular proteases
      2. Facilitates cell-to-cell communication
    • What are the two main classes of membrane transport proteins?
      1. Channel Proteins
      2. Transporter Proteins
    • What types of molecules can diffuse across the lipid membrane?
      Hydrophobic and small nonpolar molecules
    • How do facilitated transport proteins assist charged solutes?
      They shield them from membrane repulsion
    • What is the function of channel proteins?
      They create continuous pores for transport
    • How do transporter proteins facilitate diffusion?
      By inducing conformational changes upon binding
    • What is the role of ATP in active transport?
      It drives transport against concentration gradients
    • How does membrane potential affect ion transport?
      It influences the entry of cations and anions
    • What is the electrochemical gradient?
      Combination of concentration and electrical gradients
    • What is the typical membrane potential in human neurons?
      Approximately -70 mV
    • What is the effect of the Na+/K+ ATPase pump on Na+ transport?
      It creates a powerful electrochemical gradient
    • How do some channels/transporters utilize electrochemical gradients?
      They harness gradients for active transport
    • What are the key contents discussed in the study material?
      • Protein interactions with the membrane
      • Transport with the concentration gradient
      • Transport against the concentration gradient
      • Transport of glucose across the membrane
    • What are the main functions of membrane proteins?
      • Transport solutes
      • Act as receptors
      • Facilitate cell communication
      • Provide structural support
    • What is the typical electrical potential across plasma membranes?
      Negative inside and positive outside
    • What does the electrical potential across plasma membranes favor?
      Entry of cations
    • What opposes the entry of anions across plasma membranes?
      The electrical potential
    • What is the equation for the electrochemical gradient?
      Concentration gradient + electrical gradient
    • What is the approximate membrane potential of human neuronal plasma membranes?
      Approximately -70 mV
    • What does the Na+/K+ ATPase pump do?
      Effluxes Na+
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