Mic 205A Exam Questions Well Answered Latest Update 2026

MIC 205A EXAM QUESTIONS WELL ANSWERED LATEST UPDATE 2026 Which of the following microbes spreads easily through saliva (and other fluids of the body) and causes the disease infectious mononucleosis (mono)? Question options: a) Burkholderia mallei b) Vibrio fischeri c) Rhizobium spp. d) Epstein Barr virus - Answers d Which of the following microbes fixes nitrogen and has a symbiotic relationship with plant roots? Question options: a) Burkholderia mallei b) Epstein Barr virus c) Rhizobium spp. d) Vibrio fischeri - Answers c Which of the following microbes is a Gram-negative microbe primarily infecting horses and causes the disease Glanders. Question options: a) Burkholderia mallei b) Epstein Barr virus c) Rhizobium spp. d) Vibrio fischeri - Answers a This microbe is important in various ecosystems because it performs photosynthesis and thus produces oxygen. Question options: a) Clostridium tetani b) Cyanobacterium spp. c) Clostridium botulinum d) Leptospira spp. - Answers b Which of the following statements are true about Escherichia coli? Question options: a) All are correct b) The genus is Escherichia c) The species epithet is coli and it is named for the colon/large intestine d) This microbe is a common inhabitant of the human intestine - Answers a Which of the following statements is true about Streptococcus pyogenes (GAS)? Question options: a) all statements are true b) common inhabitant of nasal passages and skin of humans c) in rare cases can lead to post partum sepsis d) arrangement is clusters - Answers its not a Which of the following is NOT true about the two major categories of bacteria? Question options: a) Both categories contain peptidoglycan as part of their cell wall b) Consist of Bacteria and Archaea c) Differences between the two major catogories mostly have to do with the structures that make up the cell wall and the relative amount of peptidoglycan in the cell wall d) Consist of Gram-positive and Gram-negative - Answers its not d Which definition best fits what glycocalyx is, generally speaking? Question options: a) extracellular matrix made up of polysaccharide and/or polypeptide, where the two types are slime layer and capsule b) prevents phagocytosis, helping hide the bacterium from the immune system in the form of capsule c) enables adherence for creating bacterial communities and forming a biofilm d) keeps bacterial communities from drying out and may provide nutrients as a slime layer - Answers its not c A two-year old male was placed in the ICU with hemolytic uremic syndrome (HUS, acute kidney failure). The parents reported that the toddler had bloody diarrhea and that the family regularly consumed raw milk from a local dairy. Gram stains on stool specimens from the child and from the cattle revealed pink, rod-shaped bacteria and the clinician suspected Escherichia coli and wanted to determine the serovar. Testing reveals that the bacterium has an O-polysaccharide number 157 and flagellar antigen 7. What is the significance of the test results? Question options: a) All are correct b) The O polysaccharide number 157 is specifically referring to the type of H protein c) The two tests help reveal, in this case, what serovar of Escherichia coliis causing this child's infection d) The flagellar antigen is specifically referring to a component of the LPS - Answers c Gram negative cell walls: Question options: A) have an outer membrane B) are usually unaffected by penicillin C) do not retain crystal violet after decolorizing with ethyl alcohol (ethanol) D) all of the above are true E) only A and C are true - Answers d Short external structures made of microtubules and used for movement in some unicellular eukaryotic cells are: Question options: a) pili b) cilia c) fimbriae d) flagella - Answers b Which of the following is an organelle and most closely resembles a prokaryotic cell? Question options: a) Endoplasmic reticulum b) Mitochondrion c) Golgi complex d) Ribosome - Answers b What is true about 70S ribosomes? Question options: A) They are found free-floating in the cytoplasm of eukaryotic cells B) They are found attached to the endoplasmic reticulum (making it Rough ER) in eukaryotic cells C) They are found in mitochondria in eukaryotic cells D) All of the above E) A and B are true - Answers c What is true about 80S ribosomes? Question options: A) They are found free-floating in the cytoplasm of eukaryotic cells B) They are found attached to the endoplasmic reticulum (making it Rough ER) in eukaryotic cells C) They are found in mitochondria in eukaryotic cells D) All of the above E) A and B are true - Answers e The three domain system is based on the following: Question options: a) rRNA is found in all cells b) rRNA can be compared across different kinds of cells c) when comparing rRNA three distinct groups can be identified d) All of the above are true - Answers d Which statement is true about why the three Domain system works? Question options: A) Prokaryotic cells have 16S rRNA B) Eukaryotic cells have 18S rRNA C) Even viruses are made of cells and can be classified within a Domain D) All of the above E) A and B are true - Answers e This microbe causes an E.I.D. that is associated with outbreaks in Africa and is often traced back to consumption of bushmeat. Question options: a) Ebola virus b) Yellow Fever virus c) Merkel cell polyomavirus d) Epstein Barr virus - Answers a A 20-year-old college student who developed neck pain, a rash, and fever, reported to the campus health center. The patient was evaluated for a brain infection, and because of his symptoms, the physician ordered that a cerebral spinal fluid (CSF) sample be taken and evaluated. The CSF sample yielded diplococci bacteria that stained pink upon Gram-staining. When the diagnosis was made public health authorities immediately ordered that anyone who had been in close contact with him be screened for the infection. College-wide emergency vaccination was also initiated. What was the student diagnosed with? Question options: a) Merkel cell polyomavirus b) Francisella tularensis c) Bordetella pertussis d) Neisseria meningitidis - Answers d A 76-year old woman presents to her family doctor complaining of two days of watery diarrhea. She mentions that she recently completed a course of antibiotics to treat pneumonia. She also takes a proton pump inhibitor (PPI) daily for upset stomach/indigestion. The physician prescribes another course of antibiotics, assuming she has bacterial induced food poisoning that is causing her diarrhea and sends her home. A week later the woman is rushed to the hospital complaining of profuse watery diarrhea (10-15 times per day), severe abdominal cramping, and abdominal distension. The ER staff carefully note her history and suspect that the antibiotics and proton-pump inhibitors have made her vulnerable to the Gram-positive endospore (spore) forming bacterium: Question options: a) Clostridium tetani b) Clostridium botulinum c) Francisella tularensis d) Clostridium difficile - Answers d Which statement is NOT true about pertussis vaccination to protect infants? Question options: a) The infant does not require vaccination until 1 year of age b) Pregnant women should be vaccinated during every pregnancy c) Pregnant women should be vaccinated between 27-36 weeks of pregnancy d) Fetus receives protective antibodies in utero when the pregnant woman is vaccinated at the correct time - Answers a Which scientist applied germ theory specifically in obstetric procedures? Question options: a) Joseph Lister b) Louis Pasteur c) Robert Koch d) Ignaz Semmelweiss - Answers d Long external structures made of H protein and used for movement in a bacterium are: Question options: a) Fimbriae b) Flagella c) Cilia d) Pili - Answers b Which of the following is NOT true about vaccination? Question options: a) Developed by Edward Jenner as a method to prevent disease by Variola virus b) Involved placing Cowpox virus-infected pustule material into a lesion of the person being vaccinated c) Less effective and more dangerous than variolation at preventing smallpox d) Cowpox virus was used in this new process to prevent smallpox - Answers c Which answer best reflects what is true about the structure and staining of Gram-positive cells after being Gram stained? Question options: a) crystal violet-iodine complex is trapped in the outer membrane b) safranin is trapped in the peptidoglycan c) safranin is trapped in the outer membrane d) crystal violet-iodine complex is trapped in the peptidoglycan - Answers d What is the function of the plasma membrane? Question options: a) allows only some molecules and ions to enter, keeping others from entering b) semi-permeable membrane c) contains important enzymes for the production of energy d)