Prokaryotic Cell Structure and Function

Vocabulary flashcards based on lecture notes about Prokaryotic Cell Structure and Function.

Prokaryote

A type of cell including Bacteria and Archaea.

Bacteria

A type of prokaryote that comes in many different quantities, arrangements, shapes and sizes, typically around 1 μm to 5 μm.

Cocci

Spherical-shaped bacteria.

Bacilli

Rod-shaped bacteria.

Spiral Bacteria

Bacteria with a spiral shape.

Diplococci

Pairs of cocci bacteria.

Diplobacilli

Pairs of bacilli bacteria.

Streptococci

Chains of cocci bacteria.

Tetrad

A group of four cocci bacteria arranged in a square.

Sarcinae

A cuboidal arrangement of eight cocci bacteria.

Staphylococci

Grape-like clusters of cocci bacteria.

Streptobacilli

Chains of bacilli bacteria.

Coccobacillus

Bacteria that are oval and similar to both cocci and bacilli.

Vibrio

Comma-shaped bacteria.

Spirillum

Thick, rigid spiral bacteria.

Spirochete

Thin, flexible spiral bacteria.

Nanobacteria

The smallest bacteria, approximately 0.05 µm in size.

E. fishelsoni

The largest bacteria, approximately 600 µm in size.

Plasma Membrane

A semi-permeable phospholipid bilayer that surrounds the cell, allowing specific molecules to pass through and containing integral and peripheral carrier proteins.

Hopanoids

Sterol-like structures in bacterial membranes that promote membrane stability.

Cell Wall

A rigid layer external to the plasma membrane that protects from the environment, maintains shape, and contributes to pathogenicity.

Peptidoglycan (Murein)

A mesh-like polymer common to Gram positive and Gram negative cell walls, made of NAG and NAM sugars and unique amino acids.

NAG

N-acetylglucosamine, a sugar found in peptidoglycan.

NAM

N-acetylmuramic acid, a sugar found in peptidoglycan.

Gram Stain

A staining technique that differentiates bacteria based on peptidoglycan content, resulting in Gram positive (purple) and Gram negative (pink) classifications.

Gram Positive

Bacteria with a thick peptidoglycan layer in their cell walls.

Gram Negative

Bacteria with a thin peptidoglycan layer and an outer membrane in their cell walls.

Teichoic Acid

A component of Gram positive cell walls, made of glycerol or ribitol joined by phosphate groups, contributing to the negative charge of the cell wall.

Lipoteichoic Acid

Teichoic acids bound covalently to peptidoglycan or plasma membrane lipids in Gram positive cell walls.

Periplasmic Space

The space between the inner membrane and peptidoglycan AND between peptidoglycan and the outer membrane in Gram-negative cells, also present between the plasma membrane and cell wall in Gram-positive cells.

Braun’s Lipoprotein

The most abundant protein in the outer membrane of Gram negative bacteria, covalently joining the outer membrane to the peptidoglycan layer.

Lipopolysaccharide (LPS)

A large, complex molecule in the outer membrane of Gram negative bacteria, containing lipid and polysaccharide sections.

Lipid A

The lipid component of LPS, embedded in the outer membrane.

O Side Chain

The polysaccharide component of LPS that sticks out from the outer membrane surface and is highly immunogenic.

Porin Proteins

Trimers embedded in the outer membrane of Gram negative bacteria that allow passage of small molecules.

Glycocalyx

A sugar coat of polysaccharides and/or polypeptides surrounding the cell.

Capsule

A glycocalyx that is organized and firmly attached to the cell wall.

Slime Layer

A glycocalyx that is not organized and is only loosely attached to the cell wall.

S-Layer

The most common type of archaeal cell wall.

Pseudomurein

A peptidoglycan-like polymer found in some archaea, separating the S-layer from the plasma membrane.

Cytoplasmic Matrix

The fluid that suspends the nucleoid, ribosomes, and inclusion bodies in prokaryotic cells, approximately 70% water.

Ribosomes

Complex structures containing RNA and protein, functioning to translate mRNA into proteins (70S in prokaryotes).

Nucleoid Region

The area containing chromosomes and proteins in prokaryotes, not encased in a membrane.

Plasmid

Additional DNA external from the nucleoid region, small, circular, and double-stranded, containing non-essential genes.

Episome

Plasmids that integrate into the chromosome and are replicated with the chromosome.

Flagella

Long, hair-like appendages that extend from cells, allowing for cell movement.

Monotrichous

A single flagellum, if at one end = polar.

Amphitrichous

Two flagella, one at each pole.

Lophotrichous

Cluster of flagella at one or both poles.

Peritrichous

Flagella surrounding most of the bacteria.

Endospores

Specialized structures that store a copy of a cell’s DNA when unfavourable conditions arise until conditions become favourable again (metabolically inactive).