Cell membrane structure and function

• What model describes the cell membrane as a dynamic structure?

  Fluid Mosaic Model
• Who proposed the Fluid Mosaic Model?

  Singer and Nicolson
• What is the foundational structure of the cell membrane?

  Phospholipid bilayer
• What regulates membrane fluidity?

  Cholesterol
• What are carbohydrates attached to in the cell membrane?

  Glycolipids and glycoproteins
• What type of molecules are phospholipids?

  Amphipathic molecules
• How do phospholipids arrange themselves in a bilayer?

  Hydrophobic tails cluster inward
• What does the phospholipid bilayer act as?

  Selectively permeable barrier
• Which molecules can pass through the phospholipid bilayer via simple diffusion?

  Small, non-polar molecules
• What are the two types of membrane proteins?

  Integral and peripheral proteins
• What is the function of integral proteins?

  Transport and signal transduction
• What do peripheral proteins provide for the cell membrane?

  Structural support
• How does cholesterol affect membrane fluidity?

  Prevents tight packing at low temperatures
• In which type of cell membranes is cholesterol primarily found?

  Animal cell membranes
• What factors affect membrane fluidity?

  Temperature, saturation of fatty acids, cholesterol
• What is simple diffusion?

  Passive movement of small, non-polar molecules
• What is facilitated diffusion?

  Passive transport via channel/carrier proteins
• What is required for active transport?

  Energy (ATP)
• What is osmosis?

  Diffusion of water through aquaporins
• What are glycoproteins composed of?

  Proteins and carbohydrate chains
• What is the function of glycolipids?

  Cell recognition and adhesion
• What is the glycocalyx?

  Carbohydrate-rich layer on cell surface
• What does selective permeability depend on?

  Size and polarity of molecules
• What are aquaporins specialized for?

  Rapid water transport
• What was the Davson-Danielli Model proposed in 1935?

  A "sandwich" structure with proteins coating lipids
• Why was the Fluid Mosaic Model developed?

  To explain embedded proteins in membranes
• What is the importance of membrane structure for homeostasis?

  Regulates entry/exit of substances
• How do receptors in membranes contribute to cell signaling?

  Transmit signals like insulin binding
• What does compartmentalization in eukaryotic cells allow?

  Specialized functions of organelles
• What are the key components of the Fluid Mosaic Model?

  • Phospholipid bilayer
  • Embedded proteins (integral and peripheral)
  • Cholesterol
  • Carbohydrates (glycolipids and glycoproteins)
• What are the transport mechanisms across cell membranes?

  1. Simple Diffusion
  2. Facilitated Diffusion
  3. Active Transport
  4. Osmosis
• What are the functions of membrane proteins?

  • Transport (channel and pump proteins)
  • Receptors (signal transduction)
  • Enzymes (catalyze reactions)
  • Structural support (anchor cytoskeleton)
• What are the roles of cholesterol in cell membranes?

  • Maintains fluidity at varying temperatures
  • Prevents tight packing at low temperatures
  • Reduces excessive fluidity at high temperatures
• What are the functions of glycoproteins and glycolipids?

  • Cell recognition (immune system)
  • Cell adhesion (tissue formation)
  • Glycocalyx (protection against damage)
• What is the significance of selective permeability in cell membranes?

  • Controls substance entry/exit
  • Depends on size and polarity of molecules
  • Utilizes transport proteins for specific molecules
• What are the historical models of membrane structure?

  1. Davson-Danielli Model (1935)
  2. Fluid Mosaic Model (1972)
• What are the key takeaways regarding cell membrane structure and function?

  • Dynamic nature of membranes
  • Collaboration of components for transport and signaling
  • Balance of passive and active transport mechanisms