WGU CLINICAL MICROBIOLOGY FINAL EXAM STUDY SET (QUESTUIONS AND ANSWERS) 2023/2024

WGU CLINICAL MICROBIOLOGY FINAL EXAM STUDY SET (QUESTUIONS AND ANSWERS) 2023/2024 Bacteria - CORRECT ANSWER-Single-celled organism that do not have a cell nucleus and the membrane-enclosed intracellular structures found in most other cells (Prokaryotic cell). Gram-positive Bacteria - CORRECT ANSWER-Thick layer of peptidoglycan (20-80nm across). The peptidoglycan layer is closely attached to the outer surface of the cell membrane. Retains crystal violet stains. Lack an outer membrane and a periplasmic space. Gram-negative Bacteria - CORRECT ANSWER-Cell wall is thinner, but more complex. Only 10-20% peptidoglycan. Contains an outer membrane, leaving a very narrow periplasmic space. Does not retain crystal violet stain because of large quantities of lipoproteins and lipopolysaccharides (endotoxin). Acid-fast Bacteria - CORRECT ANSWER-Cell wall is thick, but consists of 60% lipids. Lipids make acid-fast organisms impermeable to most other stains and protect them from acids and alkalis. Stain as gram-positive. Grow slowly because the lipids impeded entry of nutrients. Endotoxin - CORRECT ANSWER-Lipopolysaccharide (LPS). Part of the outer membrane of the cell wall of gram-negative bacteria. It can cause fever and dilates blood vessels- causing BP to drop. Bacteria typically release this when they are dying, so killing them increases the concentration of this toxic substance. Antibiotics given late in the infection can cause worsening of symptoms or even death. Wall-deficient Bacteria - CORRECT ANSWER-Protected by a strengthened cell membrane that contains sterols. Example: mycobacterium paratuberculosis with Crohn's disease- a chronic disorder of the intestine. Coccus - CORRECT ANSWER-Sphere shaped bacteria Coccobacillus - CORRECT ANSWER-Short rod shaped bacteria (between cocci and bacilli) Vibrio - CORRECT ANSWER-Comma shaped bacteria Bacillus - CORRECT ANSWER-Rod shaped bacteria Spirillum - CORRECT ANSWER-Rigid, wavy shaped bacteria Spirochete - CORRECT ANSWER-Corkscrew shape bacteria Function of cell membrane - CORRECT ANSWER-To regulate movement of materials into and out of the cell by transport mechanisms. It synthesizes cell wall components, assists with DNA replication, secretes proteins, carries on respiration, and captures energy as ATP. Function of the cell wall - CORRECT ANSWER-Helps maintain the characteristic shape of the cell and prevents the cell from bursting when fluids flow into the cell by osmosis. Lies outside the cell membrane. Peptidoglycan - CORRECT ANSWER-Single most important component of the bacterial cell wall. Capsule - CORRECT ANSWER-Discrete layer of polysaccharides that protects the cell. Promotes infection by protecting the bacterial cell from engulfment by predatory protozoa or WBC (phagocytes). Also mediates adherence of cells to surfaces. Pili - CORRECT ANSWER-Tiny, hallow projections that are used to attach bacteria to surfaces. Are NOT involved in movement. Promote infection by transferring DNA amount bacteria- which in turn can transfer antibiotic resistance. Can adhere to RBC and cause blood cells to clump. Flagella - CORRECT ANSWER-Long, thin, helical appendages that allow bacteria to move. Endospore - CORRECT ANSWER-Helps the organism survive, and is not a means of reproduction. They are formed within the cells, contain very little water and are highly resistant to heat, drying, acids, bases, certain disinfectants, and even radiation. They are capable of surviving adverse environmental conditions for long periods of time. Chemotaxis - CORRECT ANSWER-Process of bacteria moving toward or away from substances in their environment. Towards- positive, Away- Negative. Bacteria that produce spores - CORRECT ANSWER-Bacillus, Clostridium Helminths - CORRECT ANSWER-Worm-like organisms living in and feeding on live hosts, receiving nourishment and protection while disrupting their hosts' nutrient absorption, causing weakness and disease. Example: Flukes, tapeworms, adult roundworms of intestine, and roundworm larvae. Zygomycota - CORRECT ANSWER-Bread molds Ascomycota - CORRECT ANSWER-Sac fungi. Yeasts. Replication by sexual reproduction. Basidiomycota - CORRECT ANSWER-Club fungi. Amanita and other mushrooms. Deuteromycota - CORRECT ANSWER-Fungi imperfecti. Soil organisms. Virus - CORRECT ANSWER-Tiny, non living particle that invades and then reproduces inside a living cell. Contain only one kind of nucleic acid- either DNA or RNA (never both). Naked virus - CORRECT ANSWER-Virus with only a nucleocapsid and no envelope. Enveloped virus - CORRECT ANSWER-Have a bilayer membrane outside their capsids. Retrovirus: Single-stranded positive-sense RNA virus - CORRECT ANSWER-Viral group that produces reverse transcriptase. Mutualism - CORRECT ANSWER-Both members of the association living together benefit from the relationship. Parasitism - CORRECT ANSWER-One organism, the parasite, benefits from the relationship, whereas the other organisms, the host, is harmed by it. Commensalism - CORRECT ANSWER-Two species live together in a relationship such that one benefits and the other one neither benefits nor is harmed. Antagonism - CORRECT ANSWER-An interaction between organisms so that one organism benefits at the expense of another. Incubation period - CORRECT ANSWER-The time between infection and the appearance of signs and symptoms. Prodromal phase - CORRECT ANSWER-Short period during which nonspecific, often mild, symptoms such as malaise and headache sometimes appear. Invasive phase - CORRECT ANSWER-The period during which the individual experiences the typical sings and symptoms of the disease. Acme - CORRECT ANSWER-Time when signs and symptoms reach their greatest intensity. Fulminating - CORRECT ANSWER-Sudden or severe Decline phase - CORRECT ANSWER-Symptoms begin to subside. The period of illness during which host defenses and the effects of treatment finally overcome the pathogen. Convalescence period - CORRECT ANSWER-Tissues are repaired, healing takes place, and the body regains strength and recovers. Physical barriers - CORRECT ANSWER-Skin and mucus membranes and the chemicals they secrete. Prevent approach and deny access to pathogens. Chemical barriers - CORRECT ANSWER-Antimicrobial substances in body fluids such as tears, saliva, mucus, gastric juices, and the iron limitation mechanisms. Lysozyme- in tears, saliva, and mucus. Interferon - CORRECT ANSWER-A small, soluble protein that is responsible for viral interference. It can also stimulate adaptive immune defenses. Increases resistance of cells to infection, slow the spread of disease. Fever - CORRECT ANSWER-Body temperature rises in response to pryogens. This mobilizes defenses, accelerates repairs, and inhibits pathogens. Complement system - CORRECT ANSWER-1. Enhance phagocytosis by phagocytes; 2. Lyse microorganisms, bacteria, and enveloped viruses directly; 3. generate peptide fragments that regulate inflammation and immune responses. Goes to work as soon as invading microbe is detected. Attacks and breaks down cell walls, attract phagocytes, and stimulates inflammation. Protozoa - CORRECT ANSWER-one-celled organisms that have a nucleus and live in water or as parasites. Fungi - CORRECT ANSWER-A special eukaryotic organism that lives by decomposing and absorbing nutrients. Dimorphic - CORRECT ANSWER-Fungus can grow as both yeast and molds. Hyphae - CORRECT ANSWER-The branching, threadlike tubes that make up the bodies of multicellular fungi. Positive sense single-stranded RNA viruses - CORRECT ANSWER-RNA genomes ready for immediate translation into proteins Negative sense single-stranded RNA viruses - CORRECT ANSWER-other RNA genomes that have to be converted into proper form to be made into protiens Classical pathway - CORRECT ANSWER-antibodies bind pathogen's antigens Lectin pathway - CORRECT ANSWER-Lectin binds to carbs on pathogen surface Reaction cascade Alternate pathway - CORRECT ANSWER--activation is by the presence of endotoxin. -causes an inflammatory reaction Dendritic cells - CORRECT ANSWER-Phagocytic cells that re involved in initiating the adaptive defense response. Langerhans cells produce immune tolerance to good bacteria, preventing overreaction of our immune system. Neutrophils - CORRECT ANSWER-Phagocytic cells that guard blood, skin, and mucus membranes against infection. Most aggressive WBC in cases where bacteria attempt to destroy tissue. Eosinophils - CORRECT ANSWER-Help turn off inflammatory reactions by releasing histamine-degrading enzymes from their granules. Destroy parasitic organisms and play a major role in allergic reactions Basophils - CORRECT ANSWER-Release histamine, a chemical that helps initiate the inflammatory response. Phagocytes - CORRECT ANSWER-Attack and remove dangerous microorganisms by eating or engulfing them. Monocyte Innate immunity - CORRECT ANSWER-1. In place since birth (genetic) 2. Universal protection 3. Responds immediately Adaptive immunity - CORRECT ANSWER-The body's acquired resistance to a specific pathogen. Active immunity - CORRECT ANSWER-Immunity that develops as a result of natural or deliberate exposure to an antigen. Passive immunity - CORRECT ANSWER-Created when ready-made antibodies are introduced into the body- the host's own immune system does not make the antibodies. Naturally acquired active immunity - CORRECT ANSWER-Produced when a person is exposed to an infectious agent. Naturally acquired passive immunity - CORRECT ANSWER-Produced when antibodies made by a mother's immune system are transferred to her offspring. Artificially acquired active immunity - CORRECT ANSWER-Produced when a person is exposed to a vaccine. Artificially acquired passive immunity - CORRECT ANSWER-Produced when antibodies made by other hosts are introduced into a new host. Example: snake antivenin injection, rabies. Antigen - CORRECT ANSWER-A substance the body identifies as foreign and toward which it mounts an immune response. Antibody - CORRECT ANSWER-A protein produced in response to an antigen that is capable of binding specifically to an antigen. B cells - CORRECT ANSWER-Develop into plasma cells that make antibodies to attack bacteria and viruses. Memory B Cells - CORRECT ANSWER-B-cell product: Ready to produce specific antibodies in the future. Helper T cells - CORRECT ANSWER-Activate B and T cells: control or limit specific immune response. Cytotoxic T cells - CORRECT ANSWER-attack foreign or body cells infected by viruses & proved CELL mediated immunity. NK Cells - CORRECT ANSWER-destroy abnormal tissue cells Memory T Cells - CORRECT ANSWER-Remember antigen and quickly stimulate immune response on reexposure. IgG - CORRECT ANSWER-Goes across the placenta , and confers with the passive immunity Most abundant antibody IgM - CORRECT ANSWER-first antibody produced in an immune response IgA - CORRECT ANSWER-Abundant in colostrum where it helps protect infants from intestinal pathogens. Found in body secretions such as tears, milk, saliva, and mucous and is attached to the linings of the digestive, respiratory, and genitourinary systems. Does not cross the placenta. IgE - CORRECT ANSWER-Plays key role in allergenic response. Also elevated in patients harboring worm parasites. IgD - CORRECT ANSWER-Attached to B cells Activates B cells