Medical Bacteriology Exam 1 Questions and Answers, Exams of Nursing

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Medical Bacteriology Exam 1 questions well answered to pass In all infectious diseases, the following events take place - correct answer ✔✔Encounter, Entry, Spread, Multiplication, Damage, Outcome (EESMDO) Infectious diseases are disorders caused by - correct answer ✔✔bacteria, viruses, fungi, parasites, or prions Examples of infectious diseases include - correct answer ✔✔strep throat, TB, urinary infection, common cold, AIDS, athlete's foot, malaria, hepatitis, COVID-19 When studying the pathogenesis of infectious diseases, it is essential to remember that the outcome of microbial infection is usually the net result of - correct answer ✔✔offensive measures taken by the microbe and counteroffensive measures taken by the host To intervene and to change the natural outcome of infection, one must accomplish a combination of the three goals: - correct answer ✔✔diagnosis, treatment, and/or prevention of the infection the bacterium/agent meets the host - correct answer ✔✔encounter the agent enters the host - correct answer ✔✔entry the agent spreads from the site of entry - correct answer ✔✔spread the agent multiplies in the host - correct answer ✔✔multiplication the agent, the host response, or both cause tissue damage - correct answer ✔✔damage the agent wins out or the host wins out or they learn to coexist - correct answer ✔✔outcome the fetus is well protected by mother's uterine environment and placenta is impermeable to most organisms EXCEPT - correct answer ✔✔Rubella, Cytomegalovirus, HIV, Treponema pallidum, Listeria Presence of microorganisms in a site of the body that may or may not lead to tissue damage - correct answer ✔✔colonization condition whereby colonization within a human host progresses to cause disease - correct answer ✔✔infection acquired diseases from agents in external environment (inhalation, ingestion, sexual contact, wound, insect bite) - correct answer ✔✔Exogenously acquired diseases acquired diseases from agents present in or on the body (cut can lead to production of pus caused by the Staphylococci that inhabit healthy skin) - correct answer ✔✔Endogenously acquired diseases Entry consists of two senses: - correct answer ✔✔ingress-entry without penetration (inhalation, ingestion; cholera and whooping cough) penetration-entry into tissues after crossing epithelial barriers (insect bites, cuts, organ transplant, blood transfusion) Spread includes two shades of meaning: - correct answer ✔✔lateral propagation and dissemination Microbe enters the body and remains confined to a specific tissue - correct answer ✔✔localized infection ex-boils from fungal skin infection infection spreading throughout the body via bloodstream or tissue fluids - correct answer ✔✔disseminated infection/systemic infection, ex-rabies, Hep A, measles, rubella time needed for the infectious agents to overcome early defenses and grow to a certain population size. - correct answer ✔✔incubation period (associated with multiplication stage) Strict pathogen examples - correct answer ✔✔Ebola virus, Plasmodium, Rabies, etc. (different from opportunists because it always causes harm once infecting humans no matter what state of immune system) commensalism is the - correct answer ✔✔most stable, but can become harmful over time (this is the relationship that exists between humans and members of their normal microbiota) 5 roles of the normal flora - correct answer ✔✔1.) Microbial antagonism: the most significant role: - Normal flora protect the host against colonization by pathogen 2.) Stimulate our immune system 3.) Provide vitamin B12 and vitamin K 4.) Can be the common source of infection (Ex. E. coli) 5.) Help digestion Why is skin a hostile place for bacteria? - correct answer ✔✔1. Crowded conditions, keep out invaders 2. Dry skin 3. High salt 4. Sloughing off of dead cells limiting factors of vagina - correct answer ✔✔lack of nutrients, low pH how does bacteria overcome property when host sweeps microbes away by liquid currents? - correct answer ✔✔adheres to epithelial cells (gonococci stick to the mucous membrane of urethra) how does bacteria overcome property when host kills microbes with host phagocytes? - correct answer ✔✔avoids being taken up (slimy capsule can impair uptake by neutrophils) or kill the phagocyte (produce toxin that punches hole in neutrophil membrane) how does bacteria overcome property when host starves microbes for lack of needed nutrients? - correct answer ✔✔derives needed nutrients from host cells (lyse RBCs and use their nutrients hemoglobin as a source of iron) how does bacteria overcome property when host inhibits growth by secreting antimicrobial factors such as cationic peptides? - correct answer ✔✔modify surface molecules (lipid A) to avoid cationic peptide bonding Pseudomembranous colitis, a type of antibiotic-associated diarrhea, is caused by - correct answer ✔✔Clostridium difficile normal biota harmful effects - correct answer ✔✔- Use vitamins - Chemical conversions normal biota beneficial effects - correct answer ✔✔- Microbial antagonsim -Stimulate immune system -provide supplemental vitamins (B12, K) Examples of normal flora influencing our health - correct answer ✔✔-fecal microbiota transplant -gut microbiota and obesity -gut microbiota and Alzheimer's Disease -cancer microbiome Bacteria with linear chromosome - correct answer ✔✔Streptomyces, Agrobacterium, Borrelia Bacteria with multiple chromosomes - correct answer ✔✔Vibrio: 2 circular Burkholderia: 3 circular Leptospira: 2 circular In prokaryotes only - correct answer ✔✔capsule, slime layer, endospores How does transcription differ in prokaryotes vs eukaryotes? - correct answer ✔✔Transcription in prokaryotes is coupled and mRNA processing is rare; transcription in eukaryotes is uncoupled and mRNA processing involves poly A at 3' end, cap at 5' end and splicing Describe "feast or famine" - correct answer ✔✔E. coli or a Bacteroides fragilis in the human colon have to cope with a 2-minute feast followed by 70 minutes of famine 20 times every day. The ileocecal valve opens every 72 minutes and delivers rich nutritional contents from the small intestine into the cecum (colon). The huge colon population devours the nutrients immediately and E. coli must use them efficiently, but fast, in order to withstand a famine for another 70 minutes. Respiration in prokaryotes vs eukaryotes - correct answer ✔✔Pro: at cell membrane Euk: in mitochondria Endospores such as Sporolactobacillus and Thermoactinomycetes contain __________ ,making them heat resistant - correct answer ✔✔calcium -dipicolinic acid Endospore examples - correct answer ✔✔Bacillus, Clostridium, Sporosarcina single flagellum at one pole - correct answer ✔✔monotrichous single flagellum at each pole - correct answer ✔✔amphitrichous two or more flagella at one pole - correct answer ✔✔lophotrichous flagella all over surface of cell - correct answer ✔✔peritrichous found in spirochetes, anchored at one end of a cell, rotation causes cell to move like a corkscrew, also known as endoflagella - correct answer ✔✔Axial filaments the smaller the cell, the less_______ it is - correct answer ✔✔limiting protects osmotic lysis and cell membrane, made of peptidoglycan (in bacteria), contributes to pathogenicity - correct answer ✔✔cell wall tolerate but cannot use oxygen - correct answer ✔✔aerotolerant anaerobes require oxygen concentration lower than air - correct answer ✔✔microaerophiles Bacterial growth curve - correct answer ✔✔lag phase, log phase, stationary phase, death phase no increase in population but preparing to grow - correct answer ✔✔lag phase logarithmic/exponential growth phase-Penicillin works best in this phase - correct answer ✔✔log phase period of equilibrium - correct answer ✔✔stationary phase population is decreasing at a logarithmic rate - correct answer ✔✔death phase importance of determining gram negative vs gram positive - correct answer ✔✔helps you narrow down which type of infection is going on within host High to Low concentration, down the gradient, no energy required for this - correct answer ✔✔facilitated diffusion Low to High, up gradient, requires energy (pumps out) creates a proton gradient - correct answer ✔✔active transport special form of active transport occurs exclusively in prokaryotes. Allows cell to accumulate certain substances. - correct answer ✔✔group translocation Bacteria use 3 strategies to protect their cytoplasmic membranes - correct answer ✔✔1. gram positives use thick multilayer peptidoglycan cell wall 2. gram negatives use outer membrane of lipid A, the core, and O antigen creating a dual membrane system and creates a periplasm outside the cytoplasmic membrane 3. acid-fast bacteria contain large amounts of waxes in their cell walls with very high lipid content Flagella is present in both prokaryotes and eukaryotes, while __________ is only present in prokaryotes and ____________ is only present in eukaryotes - correct answer ✔✔pili, cilia issues of importance for multiplication time are - correct answer ✔✔incubation time, temperature, osmotic pressure, and pH. The host defenses must also by subverted. The organisms that are acid-fast grow very slowly, dividing every 24 hours, because - correct answer ✔✔the rate of uptake of nutrients is limited by the wax all living organisms have - correct answer ✔✔ribosomes and plasma membrane Prokaryotic plasma membranes lack sterols EXCEPT for - correct answer ✔✔Mycoplasma The main function of pili is - correct answer ✔✔attachment; hold on to body cells The main function of axial filaments/endoflagella is - correct answer ✔✔motility Feast or famine requires bacteria to be - correct answer ✔✔efficient and adaptable Primary difference in capsule vs slime layer - correct answer ✔✔Capsule is more organized and slime layer is looser peptidoglycan wall contains both ____ and ______ amino acids - correct answer ✔✔L and D the peptidoglycan wall in gram positive bacteria rotates which two disaccharides? - correct answer ✔✔NAG and NAM Which part of the gram negative cell wall functions as an endotoxin? - correct answer ✔✔LPS- because of Lipid A (provokes strong immune response) H antigen is protein in - correct answer ✔✔flagella Is gram positive or gram negative more complex regarding cell wall structure? - correct answer ✔✔Gram negative, due to outer and inner membrane around peptidoglycan layer. Gram _______ is more resistant to antibiotics - correct answer ✔✔negative Why does gram positive bacteria carry a negative charge? - correct answer ✔✔Teichoic acid carries phosphate Which step in gram staining is arguably most impactful? - correct answer ✔✔Decolorization Acid fast bacteria cannot be gram stained due to - correct answer ✔✔high concentration of mycolic acid in the wax Which antibiotic inhibits the step of peptidoglycan synthesis where disaccharides are linked to a growing peptidoglycan chain? - correct answer ✔✔Vancomycin Which antibiotic inhibits the step of peptidoglycan synthesis where the transpeptidase enzyme catalyzes the cross-linking of the peptidoglycan strands in the cell wall phase of the cell wall biosynthesis? - correct answer ✔✔Penicillin (In the presence of the drug, the transpeptidase becomes confused: Instead of synthesizing an intermediate d-alanine-enzyme complex, it makes a lethal penicilloyl-enzyme complex.) Which antibiotic inhibits the step of peptidoglycan synthesis by preventing regeneration of the lipid carrier? - correct answer ✔✔Bacitracin