What is Bacteria?

What is Bacteria?

• Bacteria are small, single-celled organisms found almost everywhere on Earth.
• They are vital to the planet's ecosystems and can live under extreme conditions of temperature and pressure.
• The human body contains more bacterial cells than human cells, with most being harmless and some even helpful.

Types of Bacteria

• Bacteria are classified into four major groups based on their cell shape and physical structure:
  • Spherical (cocci)
  • Rod (bacilli)
  • Spiral (spirilla)
  • Comma (vibrios)

Structure of a Bacteria

• A typical bacterial cell consists of:
  • Cell wall
  • Plasmid DNA
  • Flagellum
  • Cytoplasm
  • Bacterial DNA (Chromosomal DNA)

Reproduction in Bacteria

• Bacteria reproduce through binary fission, an asexual mode of reproduction.
• A single bacterium divides into two identical daughter cells.
• Replication of DNA within the parent bacterium marks the beginning of the fission.
• The rate and timing of reproduction depend on conditions like temperature and availability of nutrients.

Useful Bacteria

• Not all bacteria are harmful to humans; some are beneficial in different ways:
  • Convert milk into curd (Lactobacillus)
  • Ferment food products (Streptococcus and Bacillus)
  • Help in digestion and improving the body's immunity system (Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria)
  • Produce antibiotics (Soil bacteria)

Harmful Activity of Bacteria

• Bacteria cause diseases in plants and animals, leading to indirect human impacts.
• Bacteria cause many human diseases, entering the body through openings, air, food, and water, or through skin wounds.
• Bacterial diseases harm people in two ways:
  • Interfering with normal body tissue function
  • Releasing toxins that directly attack the host
• Additionally, bacteria are linked to:
  • Cancer
  • Food spoilage
  • Allergies and chronic inflammation
  • Flesh-eating diseases
  • Infectious diseases like pneumonia, tuberculosis, and tooth decay
  • Cellulose degradation, destroying textiles and wooden articles