Lecture on Binary Fission

Introduction

• Binary fission is the process by which prokaryotic organisms, like bacteria, divide and reproduce.
• It differs from mitosis and meiosis, which occur in eukaryotic cells.

Structure of Bacterial Cells

• Components:
  • Cell wall
  • Cell membrane
  • Cytoplasm
  • Large circular strand of DNA (important genes)
  • Plasmids (non-essential genes)
  • Flagellum (not in all bacteria)

Binary Fission Process

1. Preparation for Division
   • Bacterial cell grows in size.
   • Replicates its genetic material (DNA and plasmids).
2. Division
   • DNA strands move to opposite sides of the cell.
   • Random distribution of plasmids.
   • Formation of a new cell wall.
   • Separation into two new bacterial cells.

Characteristics of Binary Fission

• It is a form of asexual reproduction.
• Rapid process under favorable conditions (e.g., every 20 minutes).

Bacterial Population Growth

• Doubling process: 1 becomes 2, 2 becomes 4, etc.
• Example calculation:
  • Given: 5 hours of doubling every 20 minutes, results in 250,000+ bacteria.

Calculation of Bacterial Growth

• Example 1: Mean division time of 30 minutes, growth over 3 hours.
  • 3 hours = 180 minutes.
  • Division cycles: 180/30 = 6.
  • Cells after 3 hours: 1 x 2^6 = 64 cells.
• Example 2: 1000 bacteria, division every 20 minutes over 4 hours.
  • 4 hours = 240 minutes.
  • Division cycles: 240/20 = 12.
  • Cells after 4 hours: 1000 x 2^12 = 4,096,000 cells.

Factors Affecting Growth Rate

• Growth depends on species and environmental conditions.
• Optimal conditions: warmth, moisture, and nutrients.

Additional Resources

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• Access additional resources via the learning platform and video descriptions.