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Module 11 in the Syllabus

The Prokaryotic Cell Images
Image gallery for study with links to larger teaching JPEGs for classroom presentation

Question Drill for The Prokaryotic Cell
Conceptual Vocabulary Self-Test

Basic Terms Crossword Puzzle

Basic Puzzle Solution

Conceptual Vocabulary
ProkaryoteProkaryotes are a group of organisms that lack a cell nucleus, or any other membrane-bound organelles.
NucleoidIn prokaryotes, the nucleoid (also known as the nuclear region, nuclear body or chromatin body) is an irregularly shaped region where the genetic material is localized.
RibosomeA ribosome is a small, dense, functional structure found in most known cells that assembles proteins and polypeptides used in cell division.
FlagellumA flagellum is a long, slender projection from the cell body, composed of microtubules and surrounded by the plasma membrane.
Cell wallA cell wall is a fairly rigid layer surrounding a prokaryotic cell, located external to the cell membrane, which provides the cell with structural support, protection, and acts as a filtering mechanism.
PeptidoglycanPeptidoglycan, also known as murein, is a polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of eubacteria.
PilusA pilus is a hairlike appendage found on the surface of many bacteria. This term and fimbria are often used interchangeably.
FlagellinFlagellin is a protein that arranges itself in a hollow cylinder to form the filament in bacterial flagellum
Gram-positiveGram-positive bacteria are those that retain a crystal violet dye during the Gram stain process.
LipopolysaccharideA lipopolysaccharide is a large molecule consisting of a lipid and a polysaccharide (carbohydrate) joined by a covalent bond.
Cell envelopeThe cell envelope is the cell membrane and cell wall plus an outer membrane, if one is present. Most bacterial cell envelopes fall into two major categories: Gram positive and Gram negative.
Outer membraneThe outer membrane refers to the outside membranes of Gram-negative bacteria.
Periplasmic spaceThe periplasmic space is the space seen between the plasma membrane and the outer membrane in the gram-negative bacteria.
GlycocalyxGlycocalyx is a general term referring to extracellular polymeric material produced by some bacteria, epithelia and other cells.
CarboxysomeThe carboxysome is a bacterial microcompartment, roughly 90-500 nm in diameter, made up of a protein shell, that contains enzymes involved in carbon fixation reactions.
FimbriaA fimbria is a proteinaceous appendage in many gram-negative bacteria that is thinner and shorter than a flagellum.
GenophoreA genophore is the DNA of a prokaryote.
S-layerA S-layer (surface layer) is a part of the cell envelope commonly found in bacteria, as well as among archaea. It consists of a monomolecular layer composed of identical proteins or glycoproteins.
EndotoxinEndotoxins are potentially toxic, natural compounds found inside pathogens such as bacteria, released mainly when bacteria are lysed.
Advanced terms that may appear in context in MCAT passages
Teichoic acidTeichoic acids are polymers of glycerol or ribitol linked via phosphodiester bonds. These acids can be found in the cell wall of gram-positive bacteria and appear to extend to the surface of the peptidoglycan layer.
Lipoteichoic acidLipoteichoic acid is a surface-associated adhesion amphiphile from Gram-positive bacteria and regulator of autolytic wall enzymes (muramidases).
FtsZFtsZ is a protein that assembles into a ring at the future site of the septum of bacterial cell division. Named after filamenting temperature-sensitive mutant Z, is a prokaryotic homologue to the eukaryotic protein tubulin.
MreBMreB is a protein found in bacteria that has been identified as a homologue of actin, as indicated by similarities in tertiary structure and conservation of active site peptide sequence.
ChlorosomeA chlorosome is a photosynthetic antenna complex found in green sulfur bacteria and some green filamentous anoxygenic phototrophs.

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