Classification and Microbial Growth - Study Notes (copy)

Classification

The systematic arrangement of organisms into groups based on shared characteristics.

Taxonomy

The science of naming, describing, and classifying organisms.

Phylogenetics

The study of evolutionary relationships among biological entities, often using genetic data.

Cell Theory

The theory that all living things are composed of cells, and all cells arise from pre-existing cells.

Prokaryotic Cells

Cells that lack a true nucleus; includes bacteria and archaea.

Eukaryotic Cells

Cells that contain a true nucleus and organelles; includes plants, animals, fungi, and protists.

Binomial Nomenclature

A two-part scientific naming system for organisms, consisting of genus and species.

Domain

The highest taxonomic rank, which classifies life into Bacteria, Archaea, and Eukarya.

Kingdom

A higher taxonomic category that groups together species sharing significant characteristics.

Strain

A genetic variant or subtype of a microorganism, often differentiated by specific traits.

Growth Media

Substances used to grow microorganisms in a laboratory setting.

Dilution Factor

A measure of how much a solution has been diluted, defined as the ratio of the volume of stock solution to the total volume after dilution.

Generation Time

The time it takes for a bacterial population to double in number, typically ranging from 1 to 3 hours.

Agar

A gelatinous substance derived from red algae, commonly used as a solid growth medium for microbes.

Exponential Growth

A pattern of growth where the population size doubles at a consistent rate.

Lag Phase

The initial phase of bacterial growth where cells adapt to their environment before division.

Log Phase

The exponential growth phase in which bacteria divide rapidly and the population size increases significantly.

Stationary Phase

The phase of bacterial growth where nutrient depletion and waste accumulation slow growth, balancing division and death.

Death Phase

The phase where the rate of cell death exceeds the rate of cell division due to unfavorable conditions.

Physical Growth Requirements

Factors such as temperature, pH, and osmotic pressure that affect microbial growth.

Chemical Growth Requirements

Essential nutrients like carbon sources and inorganic compounds required for microbial metabolism.

Obligate Aerobes

Organisms that require oxygen to survive and grow.

Facultative Anaerobes

Organisms that can grow with or without oxygen, utilizing it when available.

Obligate Anaerobes

Organisms that are harmed by oxygen and prefer anaerobic environments.

Aerotolerant Anaerobes

Organisms that do not use oxygen for growth but can tolerate its presence.

Hemocytometer

A device used for counting the number of cells in a specific volume.

Colony Forming Units (CFUs)

A measure of viable bacterial cells in a culture, typically assessed through plate counts.

Plate Counting

A method for estimating the number of viable microorganisms in a sample by counting the colonies formed on a solid medium.

Selective Media

Growth media designed to favor the growth of specific microorganisms while inhibiting others.

Differential Media

Growth media that distinguishes between different types of organisms based on their metabolic properties.

Morphological Characteristics

Physical traits of organisms used for identification and classification.

Horizontal Gene Transfer

The transfer of genetic material between organisms in a manner other than traditional reproduction, complicating species definitions.

LUCA

The Last Universal Common Ancestor, representing the shared ancestor of all current life on Earth.

Excavata

One of the eukaryotic supergroups, including protozoa like Euglena.

SAR

A eukaryotic supergroup composed of Stramenopiles, Alveolata, and Rhizaria, including kelp and dinoflagellates.

Archaeplastida

A supergroup that includes land plants and algae.

Amoebozoa

A supergroup including amoebas and slime molds.

Opisthokonta

A supergroup that includes animals and fungi.

Carl Linnaeus

The scientist known as the Father of Taxonomy, who developed the binomial naming system and hierarchical classification.

Strains of Escherichia coli

Different genetic variants of E. coli, such as O157:H7, known for producing virulence factors.

Bacterial Growth Curve

A graphical representation of the change in bacterial population size over time.

Sterilization

The process of eliminating all viable microorganisms from a material or environment, commonly achieved through autoclaving.

Ciliates

A type of protist characterized by the presence of hair-like structures called cilia.

Dinoflagellates

A group of protists known for their dual flagella and often found in marine environments.

Diatoms

Photosynthetic algae with unique silica cell walls, important in aquatic ecosystems.