Module 6 Flashcards
Microbiology is the study of?
Microbes
Name the 3 Microorganisms?
Bacteria
parasites
Fungi
Name 2 microbes that are not organisms?
Virus
Prions
Monera is?
Bacteria that is a prokaryotes(no true nucleus)
Cytoplasm
semi-fluid substance that fills inner cellular space. Primarily water with carbohydrates, lipids and enzymes.
Ribosomes
Protein synthesis center
Nucleoid
Nuclear region, not a nucleus
Inclusion bodies
granules and vesicles. Store molecules essential to cell function. i.e. glycogen
Plasmids
extra-chromosomal DNA important for transfer of genetic material.
Capsule
contributes to pathogenicity. a protective structure that serves as a defense mechanism.
Cell Wall
Provides shape and stability. Contains peptidoglycan-large polymer resembling a chain link fence. Many antibiotics target the cell wall
Cell Membrane
Regulates transport of material in and out of the cell.
About 1/2 of bacteria are what?
Motile possessing flagella
Pilli
tube-like projections not associated with motility.
What are the 2 types of pili
Facilitated adherence
exchange of genetic information.
Bacteria are characterized by their?
Shape, arrangement and their stain characteristics
Gram-positive bacteria
Purple…thick layer of peptidoglycan retains crystal violet (blue) dye.
Gram-negative bacteria
Pink…thin layer of peptidoglycan and high lipoprotein content; releases crystal violet dye when rinsed with alcohol or acetone. The safranin (pink) counterstain is retained.
Enriched media
encourages the growth of most bacteria. ex. Sheep’s blood agar (SBA)
Selective media
encourages the growth of some bacteria while inhibiting others. ex. MacConkey agar for Gram-negative organisms
Differential media
groups bacteria based on the fermentation of carbohydrates. ex. MacConkey agar is both selective and differential.
Obligate Aerobes
require atmospheric oxygen. ex. mycobacterium tuberculosis (TB)
Obligate anaerobes
require an environment with NO oxygen. Ex. Clostridium species. (botulism and tetanus)
Facultative anaerobes
can function in an oxygen-poor or oxygen-rich environment. ex. E.coli, staphylococcus, Streptococcus
Microaerophils
require reduced oxygen and increased CO2. ex. Campylobacter.
Binary fission or cell replication
describes cell division in bacteria. Do not have a cell cycle. they are continuously dividing and replicating their DNA.
Lag Phase
gear-up phase. Organisms not greatly increasing in number, but they are metabolically active. Growing, synthesizing enzymes, and producing large amounts of ATP.
Log Phase
Once the bacteria have adapted to their nutrient-rich environment, growth is exponential (logarithmic).
Log Phase
Generation time: genetically determined period of logarithmic growth. How often the organism divides varies by species (minutes to hours).
Stationary phase
when the number of new cells produced is the same as the number of cells dying. Cells are running out of nutrients.
Decline (death) Phase
The number of cells dying is greater than the number of new cells arising from division.
Symbiosis means
Living together
Mutualism
both the host and the microorganism benefit. ex. E. coli, a bacterium that lives in the large intestine.
Parasitism
One organism benefits, the other is harmed. ex. tapeworm, Malaria
Commensalism
One organism benefits, the other is neutral. ex. skin bacteria.
Pathogenic Mechanism Adherence
Bacteria use their pili to cling to the surface of host cells, multiply and form colonies.
Pathogenic Mechansim Colonization
Once in place within the host tissue, bacterial replication forms colonies, and may overcome host defenses.
Pathogenic Mechanism Formation of a capsule
In certain pathogens the capsule contributes to the organism’s virulence because this thick, polysaccharide structure helps organisms resist host defense processes.
Pathogenicity
refers to an organism’s ability to cause disease. Patho-disease genic-creation.
Hyaluronidase
attacks hyaluronic acid, the ground substance of loose connective tissue. Contributes to ease of spread. (spreading disease or bacteria)
Coagulase
Enzyme converts fibrinogen to fibrin. Fibrin is a clot-forming protein. limits spread of organism but allows the bacterium to wall itself off from the immune system.
Streptokinase and staphylokinase
Break down fibrin and prevent clotting.
Exotoxins
very powerful toxins secreted by the living bacterial cell, mostly from gram-positive species.
Endotoxins
found primarily in Gram-negative bacteria and are released only when an organism dies.
Endospores
have thickened cell walls to withstand environmental extremes such as drying and lack of nutritional sources. Dormat stage of some bacteria.
Antimicrobial
agents include substances used to specifically treat infectious microbial diseases.
Antibiotics
are antimicrobial agents containing substances derived from other organisms.
Broad Spectrum
affect a wide range of microorganisms including Gram-positive and Gram-negative bacteria
Narrow Spectrum
Affect a limited number of microorganisms
Bacteriostatic
inhibits organism growth. Stationary, stops it from growing.
Bacteriocidal
Kills the Organism
