Microbiology

Exam 1 Review

Microrgamisms

Bacterial Domain

Archaeal Domain

Eukaryotic Domain

The vas majority if microorganisms are nonpathogenic

  • the majority of pathogens are opportunistic

  • infect compromised individuals immunosuppressed wounds

  • a minority are primary pathogens

  • infect healthy individuals

Cells: the smallest structural and functional unit of life, consisting of a membrane bound compartment containing molecular machinery necessary to carry out bilogical processes such as metabolism, growth, response to enviroment and reproduction

Four Macromolecules

  • lipids

  • carbohydrates

  • proteins

  • nucleic acids

Classical Taxonomic Characteristics

Morphology- cell size, shape arrangement, spores, capsules, flagella

Staining Characteristics: simple staining, gram staining, negative staining, acid fast staining spore staining

Growth Characteristics: selective media, colony morphology

Physiological and Biochemical: metabolism, substrate utilization fermentation, respiration

Current Characteristics

  • High Resolution Morphology

  • Serological Characteristics

  • Chemotaxonomic Characteristics

  • Genomic Differences

Bacterial Components

  1. Structures for sensing and responding to the environment: flagella, pilli

  2. Structures to control growth and reproduction: nucleoid

  3. Structures to compartmentalize metabolismL cell envelope(cell wall: structure and support), cytosol (ribosomes)

Virulence Factor

A virulence factor is a microbial structure, molecule, or activity that increases an organisms ability to cause disease in its host

Virulence factors can promote attatchment, invasion, tissue damage, nutrient aquisition etc.

The Bacterial Cell wall

Peptidoglycan is the primary structural component of the cell wall

Gram + cell wall: a thick kayer of petidoglycan

Gram - cell wall: very littel peptidoglycan

  • Presence of an outer membrane containign lipopolysccaharide

Mycoplasmas lack a cell wall cause they live inside another cell

Bacterial Biofilms: large often visible structured comminotyy of microorganisms attatched to a surface

Protective slime layer sheilds bacteria from

  • Anitbiotics

  • Disinfectants

  • host immune system

Common Human Pathogens: fungi

two body types; Molds and unicellular yeasts

Dysbiosis: disruption of the normal microbiota often caused by antibiotics

Parasitic Protists (Protozoa)

Trophozoite: active feeding stage and reporductive stage

they can enter a dormant stage called cyst

Viruses: obligate intracelluer parasites