Cell Types, Microbiology, and Infectious Diseases Explained
Cell Types and Their Structure
Cell types are defined by their structure. Animal cells differ from prokaryotic cells. Higher organisms form a nucleus and cytoplasm. Plant cells are either autotrophic (self-feeding) or heterotrophic, using solar energy to produce food.
Introduction to Biology and Microbiology
Biology is the study of living beings. Microbiology is the study of microorganisms, including bacteria, viruses, and fungi, which are not visible to the naked eye. Parasitology focuses on microscopic organisms that depend on other living beings for survival, such as worms, arthropods, and protozoa.
Prokaryotic Bacteria
Prokaryotic bacteria can be aerobic or anaerobic and are studied under a microscope. According to their Gram staining, Gram-positive bacteria have a single-layered wall, while Gram-negative bacteria have a double-layered wall with two cytoplasmic membranes. Gram-positive bacteria have only one membrane. Optional elements include capsules, flagella, fimbriae or pili, and spores.
Bacterial Forms
Bacteria come in various forms: cocci, rods, glass-shaped, spirilla, and filamentous. They can be classified into three main types: cocci, bacilli, and helical.
Viruses
Viruses are acellular beings that live as parasites inside other cells. They have three parts: a viral genome, a capsid, and sometimes a membranous envelope. They are classified based on the host they parasitize (bacterial, plant, or animal viruses) and their genome (DNA or RNA).
Fungi
Fungi are eukaryotic microorganisms that can be unicellular (yeast), which are rounded, or multicellular (molds). Molds are formed by tubular structures called “hyphae,” which form a tangled, cottony mass called “mycelium.”
Protozoa
Protozoa are unicellular eukaryotic organisms with a nucleus separated from the cytoplasm by a nuclear membrane. They are classified into four groups: those with pseudopods, flagella, cilia, and those that are motionless.
Infectious Diseases
An infectious disease is caused by microorganisms that invade the body, multiply, and overcome the host’s defenses, causing damage. Pathogens are transmissible.
Epidemiological Factors
Epidemiological factors include:
- Primary: The primary reservoir is the habitat of the infectious agent (animal, human, or inactive environment) and the routes of transmission to a susceptible host.
- Secondary: Lifestyle factors linked to the system and health.
Defense Mechanisms
Defense mechanisms include:
- Natural nonspecific or innate immunity
- Specific or acquired immunity: White blood cells, antibodies, and cell-mediated immunity (CEMR)
Diagnosis and Prophylaxis
Diagnosis and prophylaxis involve:
- Data types
- Clinical history (anamnesis, signs and symptoms, exploration)
- Lab analysis (direct analysis for microorganism identification, macroscopic observation, microscopic examination with staining, sowing to obtain sufficient quantity)
- Indirect diagnosis: Immune response components
- Prophylaxis: Vaccines
Sample Processing
Sample processing includes:
- Recommendations for the patient
- Sample collection
- Conservation and initial transport
- Processing (direct examination, seeding)
- Identification: Biochemical tests
- Sensitivity tests
- Communication and typification of results
Catabolism and Anabolism
Catabolism is the set of metabolic reactions that degrade complex substances, releasing energy. Anabolism is the set of metabolic reactions used to obtain cellular constituents like amino acids, vitamins, and lipids, using energy from catabolism. Cumulative production occurs through fermentation and respiration.
Autotrophs and Heterotrophs
Autotrophs obtain energy through photosynthesis, while heterotrophs rely on organic compounds.
Nutrients
Essential nutrients include H2O, C, P, N, and S, maintained at 37°C with 90% H2O.