Characteristics of Bacteria

Characteristics of Bacteria

• Prokaryotic cells: Bacteria lack a true nucleus and membrane-bound organelles.
• Cell wall: Peptidoglycan (also known as murein) provides structural support and maintains cell shape.
• Cell membrane: Semi-permeable, allowing for the exchange of nutrients and waste.
• Size: Typically 0.5-5.0 μm in length.
• Shape: Various shapes, including spherical (cocci), rod-shaped (bacilli), and spiral-shaped (spirilla).

Types of Bacteria

• Gram-positive: Thick peptidoglycan layer, retaining Gram stain. Examples: Staphylococcus, Bacillus.
• Gram-negative: Thin peptidoglycan layer, losing Gram stain. Examples: E. coli, Pseudomonas.
• Aerobic: Require oxygen for growth. Examples: Bacillus, Pseudomonas.
• Anaerobic: Do not require oxygen for growth. Examples: Clostridium, Bacteroides.
• Facultative: Can grow with or without oxygen. Examples: E. coli, Staphylococcus.

Bacterial Metabolism

• Heterotrophic: Obtain energy by breaking down organic molecules.
• Autotrophic: Produce energy through photosynthesis or chemosynthesis.
• Fermentation: Break down glucose to produce ATP in the absence of oxygen.

Bacterial Growth and Reproduction

• Binary fission: Divide into two identical daughter cells.
• Sporulation: Form highly resistant, dormant structures (spores) to survive adverse conditions.
• Conjugation: Direct transfer of genetic material between bacteria.

Importance of Bacteria

• Decomposition: Break down organic matter, recycling nutrients.
• Nitrogen fixation: Convert atmospheric nitrogen into usable forms.
• Food production: Involved in fermentation processes (e.g., yogurt, cheese, bread).
• Human health: Normal flora maintain gut health, while some bacteria cause diseases.

Characteristics of Bacteria

• Lack a true nucleus and membrane-bound organelles, making them prokaryotic cells.
• Have a cell wall composed of peptidoglycan (murein) that provides structural support and maintains cell shape.
• Possess a semi-permeable cell membrane that allows for the exchange of nutrients and waste.
• Typically range in length from 0.5-5.0 μm.
• Exhibit various shapes, including spherical (cocci), rod-shaped (bacilli), and spiral-shaped (spirilla).

Types of Bacteria

• Gram-positive bacteria have a thick peptidoglycan layer and retain the Gram stain, with examples including Staphylococcus and Bacillus.
• Gram-negative bacteria have a thin peptidoglycan layer and lose the Gram stain, with examples including E. coli and Pseudomonas.
• Aerobic bacteria require oxygen for growth, with examples including Bacillus and Pseudomonas.
• Anaerobic bacteria do not require oxygen for growth, with examples including Clostridium and Bacteroides.
• Facultative bacteria can grow with or without oxygen, with examples including E. coli and Staphylococcus.

Bacterial Metabolism

• Heterotrophic bacteria obtain energy by breaking down organic molecules.
• Autotrophic bacteria produce energy through photosynthesis or chemosynthesis.
• Fermentation involves breaking down glucose to produce ATP in the absence of oxygen.

Bacterial Growth and Reproduction

• Binary fission involves dividing into two identical daughter cells.
• Sporulation involves forming highly resistant, dormant structures (spores) to survive adverse conditions.
• Conjugation involves the direct transfer of genetic material between bacteria.

Importance of Bacteria

• Bacteria contribute to decomposition, breaking down organic matter and recycling nutrients.
• Nitrogen-fixing bacteria convert atmospheric nitrogen into usable forms.
• Bacteria are involved in food production, such as fermentation processes for yogurt, cheese, and bread.
• Normal flora bacteria maintain gut health, while some bacteria cause diseases.