Talaro’s Foundations in Microbiology: Prokaryotic Cells and Microorganisms

Vocabulary flashcards based on Chapter 4 regarding prokaryotic cell structures, Gram staining, and bacterial classifications and shapes.

Eukaryotic cells

Cells found in animals, plants, fungi, and protists that contain membrane-bound organelles and a double-membrane bound nucleus with DNA chromosomes.

Prokaryotic cells

Cells including bacteria and archaea that have no nucleus or other membrane-bound organelles.

Metabolism

The chemical and physical life processes that occur within a cell.

S layer

A monolayer of protein used for protection and/or attachment found in some bacteria.

Fimbriae

Fine, hairlike bristles extending from the cell surface that help in adhesion to other cells and surfaces.

Pilus

An appendage used for drawing another bacterium close in order to transfer DNA to it during conjugation.

Flagellin

The protein that composes the long, thin, helical filament of a flagellum.

Basal body

A stack of rings firmly anchored in the cell wall that serves as one of the three parts of the flagellum.

Glycocalyx

A coating of molecules external to the cell wall made of sugars and/or proteins that serves protective, adhesive, and receptor functions.

Slime layer

A type of glycocalyx that is loosely organized and attached to the cell to protect against dehydration and nutrient loss.

Capsule

A highly organized and tightly attached glycocalyx that inhibits killing by white blood cells by phagocytosis.

Cell envelope

The external covering outside the cytoplasm composed of two basic layers: the cell wall and the cell membrane.

Gram-positive bacteria

A group of bacteria with a thick cell wall composed primarily of peptidoglycan ranging from $20$ to $80\,nm$ in thickness.

Gram-negative bacteria

A group of bacteria with an outer cell membrane, a thin peptidoglycan layer, and an inner cell membrane.

Peptidoglycan

A unique macromolecule composed of a repeating framework of long glycan chains cross-linked by short peptide fragments.

N-acetyl glucosamine (NAG)

One of the two alternating glycans that make up the molecular pattern of peptidoglycan.

N-acetyl muramic acid (NAM)

One of the two alternating glycans in peptidoglycan where adjacent molecules on parallel chains are bound by a cross-linkage of peptides.

Teichoic acid

A component of Gram-positive cell walls that functions in cell wall maintenance, enlargement during cell division, and stimulation of immune responses.

Lipopolysaccharide (LPS)

A component of the Gram-negative outer membrane containing a lipid portion called endotoxin that may become toxic when released.

Porin proteins

Proteins located in the upper layer of the Gram-negative outer membrane that regulate the molecules entering and leaving the cell.

Periplasmic space

The space between the cell membrane and the cell wall, which is more extensive in Gram-negative bacteria.

Gram stain

A differential stain that distinguishes bacteria based on cell wall structure: Gram-positive stains purple and Gram-negative stains red.

Fluid mosaic model

A description of the cell membrane structure as a phospholipid bilayer with embedded proteins.

Nucleoid

The dense area within a bacterial cell that contains the single, circular, double-stranded DNA chromosome.

Plasmids

Small, double-stranded, non-essential circular DNA molecules that can be manipulated and transferred between cells in genetic engineering.

Ribosomes

Sites of protein synthesis made of $60\%$ ribosomal RNA and $40\%$ protein, consisting of a $30S$ and a $50S$ subunit to form a $70S$ structure.

Endospores

Dehydrated, metabolically inactive, inert resting cells produced by some Gram-positive genera like Bacillus and Clostridium to survive adverse conditions.

Sporulation

The process of forming an endospore, allowing a cell to withstand extremes in heat, drying, freezing, radiation, and chemicals.

Germination

The process by which an endospore returns to its vegetative growth state.

Coccus

A basic bacterial shape that is spherical.