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The first half of the page is very concise notes for cramming, and the latter half is more in detail

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B2.1.1 - Lipid Bilayers as the Basis of Cell Membranes:

• Phospholipids and Bilayer Formation:
  • Phospholipids consist of a hydrophilic (polar) head and hydrophobic (nonpolar) tails.
  • In water, phospholipids spontaneously arrange into a continuous, double-layered (bilayer) structure.
• Locations of Lipid Bilayers:
  • Cell Membranes: Surrounding cells, regulating entry and exit of substances.
  • Organelle Membranes: Enclosing organelles like the nucleus, mitochondria, and endoplasmic reticulum.

B2.1.2 - Lipid Bilayers as Barriers:

• Primary Function of the Cell Membrane:
  • Acts as a Selective Barrier: Regulates the passage of molecules, maintaining internal conditions.
• Aqueous Solutions and the Lipid Bilayer:
  • Surrounds both sides of the lipid bilayer, creating an aqueous environment.
• Hydrophobic Core's Low Permeability:
  • Hydrophobic interior repels large molecules and hydrophobic particles.
  • Ensures controlled movement through the membrane.

B2.1.3 - Simple Diffusion Across Membranes:

• Simple Diffusion:
  • Passive movement of molecules from regions of high concentration to low concentration.
• Factors Affecting Diffusion Rate:
  • Concentration Gradient: Greater gradient results in faster diffusion.
  • Particle Size: Smaller particles diffuse more rapidly.
  • Polarity or Charge: Nonpolar molecules diffuse more easily.
• Examples of Simple Diffusion:
  • Oxygen and Carbon Dioxide: Essential gases move across cell membranes.

B2.1.4 - Integral and Peripheral Proteins in Membranes:

• Integral vs. Peripheral Proteins:
  • Integral Proteins: Embedded in the membrane, spanning its width.
  • Peripheral Proteins: Attached to the membrane surface.
• Impact of Hydrophobic and Hydrophilic Structures:
  • Hydrophobic regions anchor integral proteins.
  • Hydrophilic regions interact with the aqueous environment.
• Functions of Membrane-Bound Proteins:
  • Transport: Move substances across the membrane.
  • Enzyme Activity: Catalyze specific reactions.
  • Signal Transduction: Transmit signals within the cell.
  • Cell Recognition: Identify and interact with other cells.