bio chp 7 (no slides)

Receptor Binding in the Immune System

• Receptors are proteins on cell surfaces that bind to specific substances (ligands).

• Interaction between receptors and ligands is crucial for immune response.

Role of Diffusion in Cellular Processes

Introduction to Diffusion

• Diffusion involves the movement of molecules from an area of higher concentration to an area of lower concentration.

• This process is essential for cellular function, including nutrient uptake and waste removal.

Examples of Diffusion

• When sugar or salt enters the cells:

  • Changes the concentration inside the cell relative to the outside.

  • This imbalance influences the movement of water across the cell membrane.

Osmosis

• Osmosis is a specific type of diffusion focusing on the movement of water.

• Water will move from areas of low solute concentration (high water concentration) to areas of high solute concentration (low water concentration).

• This process helps maintain osmotic balance within the cell:

  • If cells take in too much water, it can lead to swelling or, in extreme cases, bursting.

Consequences of Osmosis

• When cells draw in water due to high glucose or sodium levels:

  • Can lead to a sensation of thirst (dry mouth) as it affects hydration levels in the body.

Summary of Key Points

• Receptors play a vital role in the immune response by binding to specific substances.

• Diffusion and osmosis are fundamental processes that regulate the movement of substances and maintain cell health.