Basic terms commonly used in microbiology:

General Microbiology Terms

• Microorganism (Microbe) – A microscopic organism, such as bacteria, fungi, viruses, and protozoa.
• Pathogen – A microorganism that causes disease.
• Host – An organism that harbors a microbe or pathogen.
• Infection – The invasion and multiplication of microorganisms in a host.
• Contamination – The presence of unwanted microorganisms.
• Sterilization – The process of killing or removing all microorganisms, including spores.
• Disinfection – The process of killing or inhibiting pathogens on inanimate objects.
• Antiseptic – A substance that inhibits microbial growth on living tissue.

Bacteria-Related Terms

• Prokaryote – A unicellular organism without a nucleus (e.g., bacteria).
• Gram Staining – A technique to classify bacteria as Gram-positive (purple) or Gram-negative (pink) based on cell wall structure.
• Aerobic – Microorganisms that require oxygen to grow.
• Anaerobic – Microorganisms that grow in the absence of oxygen.
• Facultative Anaerobe – Bacteria that can grow with or without oxygen.
• Obligate Anaerobe – Bacteria that cannot survive in the presence of oxygen.
• Endospore – A resistant, dormant structure formed by some bacteria (e.g., Bacillus, Clostridium).

Fungi & Viruses

• Fungi – Eukaryotic microorganisms, including molds and yeasts.
• Hyphae – Thread-like structures in fungi.
• Mycelium – A network of hyphae.
• Dimorphic Fungi – Fungi that exist as both yeast and mold forms.
• Virus – A non-living infectious agent consisting of genetic material (DNA or RNA) enclosed in a protein coat.
• Capsid – The protein coat of a virus.
• Envelope – A lipid membrane surrounding some viruses.
• Bacteriophage – A virus that infects bacteria.

Microbial Growth & Control

• Culture – The growth of microorganisms in a nutrient medium.
• Colony – A visible mass of microbial cells arising from a single cell.
• Agar – A solidifying agent used in culture media.
• Incubation – The process of maintaining optimal growth conditions for microorganisms.
• Lag Phase – The initial phase of bacterial growth where cells adjust to the environment.
• Log Phase – The phase of exponential bacterial growth.
• Stationary Phase – Growth rate slows as nutrients deplete.
• Death Phase – The phase where bacterial cells die due to lack of nutrients.

Immunology & Pathogenicity

• Antigen – A substance that triggers an immune response.
• Antibody – A protein produced by the immune system that recognizes and binds to antigens.
• Virulence – The degree of pathogenicity of a microorganism.
• Toxin – A harmful substance produced by bacteria (e.g., exotoxin, endotoxin).
• Vaccine – A preparation that stimulates immunity against a specific pathogen.