Block 9 Structural Toxin Genetic Xchange & Colonize Transmission MCQ

14 Questions | By Chachelly | Last updated: Mar 20, 2022 | Total Attempts: 212

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Block 9 Structural Toxin Genetic Xchange & Colonize Transmission MCQ - Quiz

Structural toxins, genetic exchange, gene expression Microbial colonization, infection, transmission

Questions and Answers

1.

Your patient has septicemia from a Gram-negative bacterium infection. His family members are extremely concerned that he is so sick and ask you to explain what is happening. You tell them that the body's defenses are working to counteract the infection and you show them the hematology results that indicate the patient's neutrophil count is way above the normal range. His son, who is in high school, says he has heard of neutrophils and asks what causes the neutrophil count to increase in this way. Your answer would be?
- A.
  
  The bacterium produces an endotoxin that can act directly on bone marrow cells to induce neutrophil production
- B.
  
  There is a chemokine called 1L-8 that is produce by cells called macrophages and this can recruit neutrophils
- C.
  
  The patient's lymphocytes are stimulated to produce a substance called IL-6 that can recruit neutrophils
- D.
  
  The patient's macrophages produce a substance called TNF-a that can induce neutrophils
2.

Your patient is a 19 year old student who presents with drowsiness, stiff neck and fever. Culture of the patient's blood reveals the presence of encapsulated Gram negative diplococci that can ferment glucose and maltose but not sucrose or lactose. What was the bacterial factor that was produced to induce the condition?
- A.
  
  A superantigen
- B.
  
  An enterotoxin
- C.
  
  An endotoxin
- D.
  
  An exotoxin
3.

What are the primary components of the structure marked with an arrows produced by this Gram-negative, oxidase-positive, catalase-positive diplococcus that can survive in the bloodstream?
- A.
  
  Polysaccharide, oligosaccharide, lipid A, phospholipids, and proteins
- B.
  
  Polymerized monomers of disaccharide and peptide
- C.
  
  Oligosaccharide, lipid A, phospholipid, and protein
- D.
  
  Polymerized amino acids folded with secondary, tertiary and quaternary structure
- E.
  
  Polysaccharide, nucleic acid, and proteins
4.

Which of the following characteristics would not help determine the host range of a lytic bacteriophage?
- A.
  
  The amino acid sequence of its tail fibers
- B.
  
  The methylation pattern of its DNA
- C.
  
  The frequency with which it can become a prophage
- D.
  
  The DNA sequence of its promoter region
- E.
  
  The G+C content of its genome
5.

Streptococci are referred to as being naturally competent. What does this mean?
- A.
  
  They are considered better able to adapt to new situations
- B.
  
  They can carry out transduction
- C.
  
  They can carry out transformation
- D.
  
  They can carry out conjugation
6.

Will a bacterium that receives chromosomal DNA via conjugation from a donor Hfr bacterium become capable of passing this DNA on to other bacteria?
- A.
  
  Yes, due to transfer of the tra genes
- B.
  
  Yes, due to transfer of the mob element
- C.
  
  Yes, due to transfer of the Hfr locus
- D.
  
  Maybe, if the tra genes are transferred
- E.
  
  Maybe, if the mob element is transferred
- F.
  
  No, because the tra genes are present on a plasmid not on the chromosome
7.

Which of the following best describes the accidental packaging of bacterial DNA into a bacteriophage during bacteriophage packaging for progeny phage production?
- A.
  
  Specialized transduction
- B.
  
  Accidental transduction
- C.
  
  Conjugation
- D.
  
  Generalized transduction
- E.
  
  Transformation
8.

A microbe is getting ready for sporulation using alternate sigma factors. What is the purpose of these factors?
- A.
  
  Degrading phage DNA
- B.
  
  Replicating DNA
- C.
  
  Transcribing genes
- D.
  
  Secreting peptides
- E.
  
  Translating genes
9.

A point mutation occurs in a human pathogen. It is localized to a nucleic acid affecting the expression and export of a collagenase enzyme, causing it to abnormally express collagenase activity at 25C. Which of the following changes could cause this effect?
- A.
  
  The gene encoding the collagenase, causing altered temperature stability
- B.
  
  A negative regulator of the operon, causing it to always be active via a structural change
- C.
  
  A positive regulator of the operon, causing it to have a decreased affinity for its recognition sequence
- D.
  
  The ribosome binding site, allowing more efficient translation
- E.
  
  A sensor kinase, causing it to always be active via a structural change
10.

You are discussing the different types of hepatitis with a patient who states that he is certain that all hepatitis viruses are similar. You thus go on to state that Hepatitis A virus is adapted to its mode of transmission, which is quite different from that of Hepatitis B. What is this important feature about Hepatitis A that is important for transmission?
- A.
  
  It has no envelope
- B.
  
  The virus kills the cell it infects
- C.
  
  It has a positive sense, single, strand of RNA
- D.
  
  It can bind to ICAM-1 (CD54)
11.

Your patient is in his late 30's and with a disheveled appearance. He is emaciated and dirty. He is pyrexic (102 F) and complains of fatigue, anorexia and palpitations. Upon examination you notice needle marks on both arms. You order a series of blood tests and cultures at 2 hour intervals and the laboratory returns an identification of Gram-positive, catalase and coagulase positive, cocci. What is the organism?
- A.
  
  Staph. Aureus
- B.
  
  Strep. Agalactiae
- C.
  
  Staph. Epidermidis
- D.
  
  Strep. pyogenes
- E.
  
  Viridans group of streptococci
12.

Your patient is in his late 30's and with a disheveled appearance. He is emaciated and dirty. He is pyrexic (102 F) and complains of fatigue, anorexia and palpitations. Upon examination you notice needle marks on both arms. You order a series of blood tests and cultures at 2 hour intervals and the laboratory returns an identification of Gram-positive, catalase and coagulase positive, cocci. If you examine the patient further, which of the following signs might you expect to find?
- A.
  
  Winterbottom's sign
- B.
  
  Nikolsky's sign
- C.
  
  Osler’s nodes
- D.
  
  Brudzinski's sign
- E.
  
  Kernig sign
13.

What is your diagnosis for the patient ? Your patient is in his late 30's and with a disheveled appearance. He is emaciated and dirty. He is pyrexic (102 F) and complains of fatigue, anorexia and palpitations. Upon examination you notice needle marks on both arms. You order a series of blood tests and cultures at 2 hour intervals and the laboratory returns an identification of Gram-positive, catalase and coagulase positive, cocci.
- A.
  
  Bacterial endocarditts
- B.
  
  Streptococcal pneumonia
- C.
  
  Toxicity from injecting contaminated heroin
- D.
  
  Bacterial meningitis
- E.
  
  Osteomyelitis
- F.
  
  He is a ROSS student, Just tired of studying micro/immuno
14.

Which of the following is an example of localized spread?
- A.
  
  Spread to the proximal lymph nodes by infected antigen presenting cells (dendritic cells and macrophages)
- B.
  
  Spread by infected lymphocytes through lymphocyte recirculation
- C.
  
  Spread by syncytia formation
- D.
  
  Vertical spread from the mother to her foetus by macrophages
- E.
  
  None of the above choices is an example of localized spread