Characteristics of Bacteria

Single-celled organisms lacking a nucleus, mitochondria, Golgi bodies, and endoplasmic reticulum. They reproduce asexually.

Organisms with a nucleus, mitochondria, Golgi bodies, and endoplasmic reticulum. They can be single-celled or multicellular.

A type of eukaryote that can be either single-celled (yeast) or filamentous (mold). They can be parasitic or free-living.

A type of prokaryote that lacks a nucleus and other internal membrane-bound organelles. They have a single, circular chromosome.

A structure that contains the genetic material of a eukaryote. It is surrounded by a membrane.

A classification system dividing life into three domains: Archaea, Bacteria, and Eukarya.

A thin, rigid layer surrounding the cell membrane of bacteria, providing structural support and protection.

A specialized structure in some bacteria that allows them to survive harsh conditions.

A collection of microorganisms living together in a community, usually on a surface.

A population of cells with similar characteristics, including biochemical makeup, shape, Gram stain reaction, oxygen requirements, and more.

A group of related genera.

Consists of species that differ from each other in certain ways but are related.

A group of similar families.

A group of similar orders.

A group of similar classes.

The highest level of classification, distinguished by unique molecular analysis.

A genetic variant or subtype of a microorganism.

A thin, slimy layer of bacteria that can adhere to surfaces. They are highly resistant to antibiotics and disinfectants due to their protective barrier.

Microorganisms that thrive in cold temperatures, with optimal growth between 0°C and 15°C. They can still grow at freezing temperatures.

Microorganisms that flourish at moderate temperatures, typically between 30°C and 35°C. They are the most common type of bacteria found in humans and animals.

Microorganisms adapted to hot environments, with optimal growth above 50°C and some even surviving at temperatures above 60°C.

The movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration. It is a key factor affecting microbial growth.

A process where a single bacterial colony is repeatedly transferred to new growth media, creating many identical cultures.

The visible characteristics of a bacterial colony, such as shape, color, size, and odor.

The time it takes for a single bacterial cell to divide into two cells. This is an important indicator of bacterial growth rate.

A period of time when bacteria are adjusting to their environment and preparing for growth but are not yet actively dividing.

The characteristics of bacteria observed under a microscope, including shape, arrangement, and gram staining.

A dye used in the Gram stain technique, which is a staining method used to differentiate bacterial species based on their cell wall composition.

A staining method used to differentiate bacterial species based on their cell wall composition. It involves four main steps: application of crystal violet, iodine solution, decolorizer, and counterstain (safranin).

A classification of bacteria based on their shape. Common types include cocci (spherical), bacilli (rod-shaped), and spirochetes (spiral-shaped).

A rapid period of bacterial growth where cells are dividing at their maximum rate. It is a crucial stage for the proliferation of bacteria.

A thick layer of peptidoglycan that forms the cell wall of Gram-positive bacteria.

A type of bacterial cell wall structure that retains the crystal violet dye during the Gram stain procedure, resulting in a purple color under a microscope.

A type of bacterial cell wall structure that loses the initial crystal violet dye during the Gram stain procedure and picks up the counterstain (safranin), resulting in a pink/red color under a microscope.

A thin layer of peptidoglycan, along with an outer membrane containing lipopolysaccharide, which forms the cell wall of Gram-negative bacteria.

Exterior protein filaments that extend from the bacterial cell surface and aid in bacterial movement.

A specific stain used to classify bacteria into two major groups: Gram-positive (stain purple) and Gram-negative (stain red/pink).

A process where bacteria multiply and increase in number under suitable conditions. It is influenced by factors like temperature, nutrient availability, and pH.

Protein fibers extending from the bacterial cell surface that facilitate attachment to surfaces.

Protective outer layers surrounding some bacterial cells. They are typically made of polysaccharides and help bacteria evade the host's immune system.