Micropara Midterm

Microorganisms

Microorganisms

Organisms found everywhere, present before humans, also known as microbes, crucial for Earth's biomass, influencing evolution and survival of plants and animals.

Microbiology

Branch of biology studying microorganisms and their impact on living things.

Microbial Cells

Emerged 3.8 to 4.3 billion years ago, survived without oxygen for 2 billion years, phototrophic microorganisms appeared 1 billion years ago.

Cell Theory

All organisms are made of cells, proposed by Robert Hooke.

Spontaneous Generation Theory

Disproved theory that life could arise spontaneously from nonliving matter.

Koch’s Postulate

Criteria to identify disease-causing pathogens.

Diversity of Microorganisms

Microbes are abundant, diverse, and influential in ecosystems, providing essential benefits.

Impact of Microorganisms

Cause diseases, aid in agriculture, food production, industry, and environmental cleanup.

Prokaryotic Cell

Simple cell lacking a true nucleus, with specific shapes like bacilli, cocci, and spirilla.

Eukaryotic Cell

Contains a true nucleus, found in single-celled and multicellular organisms, undergoes mitosis/meiosis.

Virus

Acellular, parasitic, composed of DNA or RNA surrounded by a protein coat, reproduces inside host cells.

Viroids

Circular RNA infectious in plants, lacking a capsid.

Prions

Protein-only infectious agents causing neurodegenerative diseases.

Cell Division

Process where a parent cell divides into daughter cells, occurring through mitosis and meiosis.

Taxonomy

Science of classifying organisms, based on morphological, physiological, molecular, ecological, geographic, and behavioral characteristics.

Identification

The process of determining a particular organism belongs to a recognized taxon.

Artificial System

Classification based on shared characteristics not closely related genetically.

Natural System

Classification with predictive characteristics and genetic similarities.

Phylogenetic System

Classifying organisms based on descent from a common ancestor.

Phenotypic Classification System

Groups based on observable characteristics, not genetic similarity.

Genotypic Classification System

Considers characteristics of the genome for classification.

Family

Group of organisms with a common attribute, may contain multiple genera.

Genus

Grouping similar genera into common families, used for classification of plants and animals.

Species

Population or groups that can interbreed freely within and among themselves.

Subspecies

Taxonomic subgroups within a species.

Clone

Population of cells derived from a single parent cell and identical.

Strain

Pure cultures of the same species that are not identical in all ways.

Nomenclature

Rules governing microbial naming, based on binomial nomenclature.

Identification Method

Process of delineating a microorganism's key features.

Genotype

Organism's genetic makeup, all its DNA.

Phenotype

Expressed properties of an organism, proteins.

DNA Replication

Process of copying DNA to produce two identical DNA molecules.

Transcription

Synthesis of RNA from a DNA template.

Translation

Process of protein synthesis from mRNA.

Mutation

Heritable alteration in the base sequence of genetic material.

Penetrating power

Beta particles have greater penetration than alpha particles due to their smaller size.

Neutrons

Highly penetrant particles that can cause severe damage to living tissues and genetic material.

Chemical Mutagens

Classified into 4 groups based on their specific reactions within DNA.

Deaminating Agents

Cause the loss of the amino group in DNA, e.g., nitric oxide, nitrous acid.

Base Analogs

Resemble purines and pyrimidines, inducing mutations by replacing normal bases during DNA replication.

Alkylating Agents

Donate alkyl groups to molecules, leading to mutagenic and recombinogenic effects.

Intercalating Agents

Insert between DNA bases, causing frameshift mutations during replication.

Vertical Gene Transfer

Genetic material transfer by descent during cell division.

Horizontal Gene Transfer

Movement of genes between non-directly related cells through transformation, conjugation, or transduction.

Transformation

Uptake of exogenous DNA from the environment, involving recombination and integration into the recipient's genome.

Conjugation

Plasmid-mediated DNA transfer between bacterial cells requiring cell-to-cell contact.

Transduction

Transfer of genetic information between cells mediated by a virus particle, not requiring direct cell contact.

Metabolism

Series of biochemical reactions for breaking down or synthesizing metabolites in cells.

Macronutrients

Nutrients required in large amounts for microbial growth.

Micronutrients

Nutrients required in minute amounts for microbial growth.

Continuous culture

A type of open system used to control specific growth rate and cell density independently, with the chemostat being the most common type.

Culture media

Laboratory cultures of microorganisms grown in either defined media, with a known exact composition, or complex media, made from digests of microbial, animal, or plant products.

Total Cell Count

Estimating microbial cell numbers through methods like microscopic counting, which can be performed on dried slides or liquid samples.

Viable cell

A cell capable of dividing and forming offspring, often measured using methods like spread plate or pour plate methods.

Direct Measurement of Microbial Growth

Methods like plate count, serial dilution, pour plates, and spread plates used to measure bacterial populations.

Indirect Methods for Estimating Bacterial Numbers

Techniques like turbidity measurement, spectrophotometry, metabolic activity, and dry weight determination.

Sterilization

The removal or destruction of all living microorganisms, commonly achieved through methods like heating or filtration.

Disinfection

A process targeting pathogens using agents called disinfectants, which may not eliminate all microorganisms.

Pathogenesis

The manner in which diseases develop, involving concepts like adherence, colonization, invasion, and factors influencing microbial growth and virulence.

Normal flora

Microorganisms residing in the body without causing infection, influenced by factors like nutrients, host defenses, and microbial antagonism.

Tissue destroying enzymes

Enzymes such as hyaluronidase, collagenase, streptokinase, and protease that break down host tissues and access nutrients.

Mucosal surface defense

Host mucosal surfaces contain immune substances like lysozyme and IgA antibodies to prevent pathogen adherence.

Exotoxins

Toxic proteins that inhibit host cell function or kill host cells, including AB toxins, cytolytic toxins, and superantigen toxins.

AB Toxins

Exotoxins with A and B subunits where B binds to host cells and facilitates A subunit transfer, causing cell damage.

Cholera Enterotoxin

AB-type exotoxin produced by Vibrio cholerae causing severe diarrhea and dehydration.

Cytotoxins and Superantigen Exotoxins

Toxic proteins that lyse host cells and trigger immune responses, causing cell death and toxic shock syndrome.

Endotoxin poisoning

Symptoms include fever and intestinal distress due to toxic lipopolysaccharides in gram-negative bacteria.

Toxic Shock Syndrome (TSS)

Systemic effects of toxic superantigens from S. aureus or S. pyogenes causing tissue damage and necrosis.

Lipopolysaccharide (LPS)

Major component of gram-negative cell outer membrane with O-specific polysaccharide, core polysaccharide, and lipid A subunits causing fever by stimulating cytokine release.