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test 4
pathogens
| Question | Answer |
|---|---|
| what is a term that refer to an organism's ability to cause disease. Technically, is used with respect to differences between microbial species | pathogenicity |
| what is a term that refer to an organism's ability to cause disease. denotes differences between strains of the same species. | virulence |
| what 4 things must a microorganism do to cause disease? | 1. maintain a reservoir before and after infection (humans, animals, environment, etc.), 2. leave the reservoir and gain access to the new host, 3. colonize the body, 4. harm the body. |
| whether or not a person actually contracts an infectious disease after exposure to a particular potentially pathogenic bacterium depends on? | the microorganism, number of bacteria that enter the body, person's innate and adaptive immune defenses |
| what kind of bacteria that can swim chemotactically toward mucosal surfaces may have a better chance to make contact with the mucous membranes, attach, and colonize. | Motile bacteria |
| Because of their thinness, their internal flagella (axial filaments), and their motility, what are more readily able to penetrate host mucous membranes, skin abrasions, etc., and enter the body. | spirochetes |
| Motility and penetration may enable the what to penetrate deeper in tissue and enter the lymphatics and bloodstream and disseminate to other body sites. | spirochetes |
| uses flagella, to swim through mucus layer of stomach, adhere to epithelial cells of mucous membranes. Here pH near neutral,produces acid-inhibitory protein blocks acid secretion by cells in the stomach. releases toxins that damage gastric mucosa. | Helicobacter pylori |
| Streptococcus pyogenes produces what enzyme that lyses the fibrin clots produced by the body in order to localize the infection & facilitate spread of the bacterium from the localized site to new tissue. | streptokinase |
| Streptococcus pyogenes produces what enzyme that degrades cell-free DNA found in pus and reduces the viscosity of the pus, facilitate spread of the bacterium from the localized site to new tissue. | DNase |
| what is The Ability to Adhere to Host Cells and Resist Physical Removal | producing pili, cell wall adhesin proteins, and/or biofilm-producing capsules. |
| the physical attachment of bacteria to host cells can also serve as a signal for the activation of genes involved in bacterial virulence. This process is known as? | signal transduction. |
| how are certain bacteria able to: 1) adhere to and colonize different cell types with different receptors, and 2) evade antibodies made against the previous pili. | By genetically altering the adhesive tips of their pili |
| what are proteins found in cell wall of various bacteria binds to specific receptor molecules on the surface of host cells enable the bacterium to adhere to cell in order to colonize, resist physical removal. | adhesins |
| Many normal flora bacteria produce a capsular polysaccharide matrix or glycocalyx to form what on host tissue. consists layers of bacterial populations adhering to host cells and embedded in a common capsular mass. Dental plaque Inner ear infections | a biofilm |
| Some bacteria produce adhesin molecules called what that activate the host cell's cytoskeletal machinery enabling bacterial entry into the cell by phagocytosis. | invasins |
| By entering the cytoplasm of the host cell, it has what and is able to protect the bacteria from complement, antibodies, and certain other body defenses. | a ready supply of nutrients |
| Streptococcus pneumoniae produces what, an invasin that enables the bacterium to enter host cells where it can resist phagocytosis. it is also thought to aid the bacterium in entering the blood and the meninges. | phosphorycholine |
| proteins Streptococcus pyogenes (Group A beta streptococci) enables the bacterium to invade epithelial cells. This is thought to help maintain persistent streptococcal infections and enable the bacterium to spread to deeper tissues. | F protein and M-protein |
| Often the ability to be pathogenic is directly related to the bacterium's ability to do what? | compete with host tissue and normal flora for limited nutrients. |
| One reason the generation time of bacteria growing in the body is substantially slower than in lab culture is because of what? In fact this is a major reason why the overwhelming majority of bacteria found in nature are not harmful to humans. | essential nutrients are limited |
| is essential for both bacterial growth and human cell growth. bacteria compete for nutrients by synthesizing specific transport systems or cell wall components capable of binding limiting substrates and transporting them into the cell. | iron |
| Bacteria synthesize iron chelators (compounds capable of binding iron) called what? Many are excreted by the bacterium into the environment, bind iron, and then re-enter the cell. Others found on cell wall, bind iron and transport it to bacterium. | siderophores. |
| The ability of bacterial iron chelators to compete successfully with the body's iron chelators as well as those of normal flora is what? | may be essential to pathogenic bacteria. |
| what are the other Ability to Compete for Iron and Other Nutrients Some bacteria produce in addition to their own siderophore, they produce what? in this way take iron from other bacteria. | receptors for siderophores of other bacteria |
| what are the other Ability to Compete for Iron and Other Nutrients a number of pathogenic bacteria are able to bind human iron chelators like what? and use that as their iron source. | transferrin, lactoferrin, ferritin, and hemin |
| what are the other Ability to Compete for Iron and Other nutrients a number of bacteria are able to produce what that kill host cells only when iron concentrations are low. the bacteria can gain access to the iron that was in those cells. | exotoxins |
| surface of the microbe must be attached to the cytoplasmic membrane of the phagocyte. Attachment of microorganisms is necessary for ingestion and may be unenhanced or enhanced. | phagocytosis |
| is a general recognition of what are called pathogen-associated molecular patterns - common in microbial cell walls but not found on human cells | Unenhanced attachment |
| pathogen-associated molecular patterns - common in microbial cell walls but not found on human cells bind to what in unenhanced attachment phagocytocis? | glycoprotein known as endocytic pattern-recognition receptors |
| is the attachment of microbes to phagocytes by way of an antibody molecule called IgG or two proteins produced during the complement pathways called C3b and C4b. | Enhanced attachment |
| Molecules such as IgG, C3b, and C4b that promote enhanced attachment are called what? | opsonins |
| are a series of serum proteins that when activated participate in four important body defense functions. These include: inflammation, Phagocyte chemotaxis, Opsonization Lysis of biological (bacterial) menbranes | complement proteins |
| enable many organisms to resist phagocytic engulfment. can interfere with the bodys complement pathways in a number of ways | Capsules |
| causes fibrin clots to form around the organism that help enable it to resist phagocytosis. | Coagulase |
| deliver proteins that depolymerize the actin microfilaments needed for phagocytic engulfment into the phagocytes, bacterium produces pore-forming proteins that create a pore spanning not only the bacterium's cytoplasmic membrane and outer membrane, | Type III Secretion System in Bacteria |
| Bacteria resist phagocytic destruction and serum lysis by a variety of means, some include: | escape from the phagosome into the cytoplasm prior to the phagosome fusing with a lysosome Prevent phagosome from fusing with lysosome by inserting Por proteins Produce enzymes that kill phagosome |
| One of the major defenses against bacteria is the immune defenses' production of antibody molecules against the organism. The "tips" of the antibody have shapes that have a complementary shape to portions of bacterial proteins and polysaccharides called | epitopes |
| what are some ways bacteria can Avoid Antibodies? | changing the adhesive tips of their pili, vary other surface proteins, coat themselves with host proteins |
| Virulence factors that damage the host include | pamps that bind to host cells causing them to synthesize and secrete inflammatory cytokines and chemokines, exotoxins, autoimmunity |
| is when the body's immune defenses mistakenly attack the body and sometimes certain bacteria can serve as a trigger for this response. | autoimmunity |
| are protein toxins usually secreted from a living bacterium but also released upon bacterial lysis. superantigens, A-B toxins | exotoxins |
Created by:
malcolmmicro