Prokaryotic Anatomy & Clinical Case

Vocabulary flashcards for Prokaryotic Anatomy & Clinical Case lecture.

Bacterial Sepsis

The proliferation of pathogens in the normally sterile blood or tissue.

Healthcare-Associated Infections (HAIs)

Infections acquired while receiving treatment in a health care facility; also known as nosocomial infections.

Gram Stain

A differential stain that uses crystal violet, iodine, alcohol, and safranin to classify bacteria based on their cell envelope structure.

Gram-negative cell walls

Cell walls with an outer membrane rich in lipids and a thin layer of peptidoglycan.

Gram-positive cell walls

Cell walls with a thick layer of peptidoglycan and no outer membrane.

Extracellular

Outside the plasma membrane.

Intracellular

Inside the plasma membrane.

Capsule Stain

A negative stain that stains everything except the carbohydrate capsule, used to identify encapsulated strains of bacteria.

Bacterial Cell Wall

Provides structure, prevents osmotic lysis, and protects the plasma membrane of bacterial cells; made of peptidoglycan.

Peptidoglycan

A polymer of repeating glycans (disaccharide) crosslinked by polypeptides, present in some amount in most bacteria.

Glycans

Glycans made up of two carbohydrates: N-acetylglucosamine (NAG or “G”) and N-acetylmuramic acid (NAM or “M”).

Teichoic acids

Link cell wall to plasma membrane and link layers of peptidoglycan in Gram-positive bacteria; carry a negative charge and regulate movement of cations.

Thin peptidoglycan

Located in the periplasm between the plasma membrane and outer membrane in Gram-negative bacteria.

Outer membrane

Helps evade host defenses and acts as a barrier to detergents, antibiotics, and digestive enzymes in Gram-negative bacteria; made of lipoproteins, phospholipids, and LPS.

Porins

Proteins that form channels through the outer membrane of Gram-negative bacteria.

LPS

Lipopolysaccharide made up of O polysaccharide and Lipid A.

O polysaccharide

Functions as antigen (e.g., E. coli O157:H7) in LPS.

Lipid A

An endotoxin embedded in the top layer of LPS.

Imipenem

Inhibits peptidoglycan cell wall synthesis and is effective against both gram-positive and gram-negative bacteria.

Polymyxin

Binds to and neutralizes lipid A, reducing its impact.

Glycocalyx (Capsule)

Polysaccharide, polypeptide, or both; viscous, gelatinous coat outside the cell wall that prevents phagocytosis and contributes to the virulence of the bacterium.

Capsule

Neatly organized and firmly attached type of glycocalyx.

Slime layer

Unorganized and loose type of glycocalyx.

Biofilms

Microbial communities where bacteria communicate cell-to-cell via quorum sensing, share nutrients, and shelter bacteria from harmful environmental factors.