The Immune Response and Cell Biology

Introduction

• Sneezing incident leading to virus entry into the lungs.
• Importance of understanding cell structure and function in relation to the immune response.

Cell Structure

• Cells: Basic unit of life for all living organisms.
  • Types: Bacteria (one-celled) to Blue Whales (multicellular).
• Cell Membrane:
  • Surrounds and protects cell's inner components.
  • Made of fats and proteins; semi-permeable (allows some substances to pass through).
  • Features tiny projections that serve various functions (adhesion, nutrient binding).

Difference between Animal and Plant Cells

• Animal Cells: Have cell membranes only.
• Plant Cells: Have both cell membranes and rigid cell walls made of cellulose (provides structure).

Virus Entry and Immune Response

• Virus Attachment:
  • Virus masquerades as a friend to enter the cell by attaching to membrane projections.
• Immediate Response:
  • Cell recognizes the virus as an enemy.
  • Special enzymes chop the virus into pieces, one piece is sent out to warn neighboring cells.
• Antibody Production:
  • Neighboring cell receives the warning and initiates antibody production in the nucleus.
  • Nucleus: Contains DNA, the blueprint for cell functions.
  • Specific DNA section provides instructions for making antibodies.

Messenger RNA (mRNA)

• Role of mRNA:
  • Enzymes copy DNA instructions into mRNA.
  • mRNA exits nucleus to reach a ribosome for protein synthesis.

Ribosome Function

• Ribosomes:
  • Up to 10 million per cell, found on the endoplasmic reticulum (ER).
  • Reads mRNA instructions, links amino acids to create antibody proteins.

Protein Secretion

• Golgi Apparatus:
  • Packages antibodies into bubbles made from the cell membrane material.
  • Provides directions for delivery outside the cell.
• Process Summary:
  • Antibody bubble fuses with the cell membrane and ejects antibodies into the body.
  • Leftover bubble is recycled by lysosomes.

Energy Supply

• Mitochondria:
  • Generate energy (ATP) by combining oxygen and electrons from food.
  • ATP powers cellular processes.
• Plant Cells:
  • Contain chloroplasts.
  • Use light energy, CO2, and water to produce oxygen and sugars (chemical energy).

Conclusion

• The collaboration of all cell types is crucial for proper function and immune response.
• Estimated total cells in the human body: 37 trillion.