Micro Exam 2 HW Questions Flashcards

Which genes can be transferred by all three methods of horizontal gene transfer?

a. Toxin Production

b. Capsule Production

c. F Factor

d. Drug Resistance

Each of the following statements concerning the mechanism of action of antimicrobial drugs is correct EXCEPT:

a. Erythromycin is a bacterial drug that disrupts cell membranes by a detergent-like action.

b. Vancomycin acts by inhibiting peptidoglycan synthesis.

c. Aminoglycosides such as streptomycin are bacterial drugs that inhibit protein synthesis.

d. Quinolones, such as ciprofloxacin, act by inhibiting the DNA gyrase of bacteria.

Which of the antibiotics below inhibits protein synthesis by binding to the 30S ribosomal subunit?

a. Sulfonamides

b. Rifampin

c. Aminoglycans

d. Chloramphenicol

e. Penicillins

Which of the following modes of action would be MOST selectively toxic against bacteria?

a. Preventing cell wall synthesis

b. Interrupting ribosomal function

c. Inhibiting DNA replication

d. Dissolving the cell membrane

Which class(es) of antibiotic inhibit(s) bacterial RNA polymerase?

a. Aminoglycosides

b. Chloramphenicol

c. Sulfonamides

d. Penicillins

e. Rifampin

The lac operon is usually in the _____ position and is activated by a/an ____ molecule.

a. On, Repressor

b. On, Inducer

c. Off, Inducer

d. Off, Repressor

The emergence of antibiotic-resistant bacteria, especially in enteric gram-negative rods, is a medically important phenomenon. This most commonly occurs by a process that involves a sex pilus and the subsequent transfer of plasmids carrying one or more transposons. Which one of the following is the name that best describes this process?

a. Transduction

b. Conjugation

c. Transformation

d. Transposition

e. Translocation

Which of the following events is MOST likely to be due to bacterial conjugation?

a. A gene encoding resistance to gentamicin in the Escherichia coli chromosome appears in the genome of a bacteriophage that has infected E. coli.

b. An encapsulated strain of Streptococcus pneumoniae acquires the gene for capsule formation from an extract of DNA from another encapsulated strain.

c. A strain of Corynebacterium diphtheriae produces a toxin encoded by a prophage.

d. A strain of Pseudomonas aeruginosa produces beta-lactamase encoded by a plasmid similar to a plasmid from another gram-negative organism.

Microbes that are the target(s) of pasteurization include:

a. ( c) Salmonella species

b. (a) Clostridium species

c. (b) Mycobacterium species

d. (d) Both (b) and ( c)

Each of the following statements regarding the killing of bacteria is true EXCEPT:

a. Iodine kills by causing the formation of thymine dimers in bacterial DNA

b. A 70% solution of ethanol kills more effectively than absolute (100%) ethanol

c. The pasteurization of milk kills pathogens but allows many organisms and spores to survive

d. An autoclave uses steam under pressure to reach the killing temperature of 121 degrees Celsius

Which immune system cell would most likely recognize a cell that has been infected by a virus?

a. CD4+ T-cell

b. CD8+ T-cell

c. B-cell

d. Neutrophil

Because you can never find parking at UAB, you decide to ride a bike to school. Unfortunately, you trip over the bike rack and cut open your leg. A few days later, the wound is swollen, has a red color, and hurts. Which term below would refer to the pain associated with the would

a. Calor

b. Tumor

c. Dolar

d. Rubor

Each of the following statements about the killing of bacteria is correct EXCEPT:

a. Silver nitrate can inactivate bacterial enzymes

b. Ultraviolet light can degrade bacterial capsules

c. Lysozymes in tears can hydrolyze bacterial cell walls

d. Detergents can disrupt bacterial enzymes

Which of the following describes humoral immunity?

a. The role of inflammation in the immune response

b. The role that circulating antibody plays in preventing infection

c. The role of CD8+ T-cells in lysising pathogen-infected cells

d. The recruitment of neutrophils to sites of infection

True or False. The innate immune response improves with time and exposure to pathogens.

Upon the second exposure to a particular pathogen, the host’s immune response may be faster and stronger than that in the first immune response. Which term below best describes this?

a. Inflammation

b. Secondary Immune Response

c. Innate Immunity

d. Primary Immune Response

Which of the following is associated with MHC class II?

a. CD8+ T-cells

b. CD4+ T-cells

c. Neutrophils

d. B-cells

An effective treatment for a cutaneous mycosis like tinea pedis would be?

a. Miconazole

b. Penicillin

c. Griseofulvin

d. Doxycycline

Your case is a 6-year-old boy with papular and pustular skin lesions on his face. A serious “honey-colored” fluid exudes from the lesions. You suspect impetigo. A gram stain of the pus reveals many neutrophils and gram-positive cocci in chains. If you culture the pus on blood agar, which one of the following would you most likely see?

a. Small non-hemolytic colonies containing bacteria that grow in 6.5% NaCl.

b. Large non-hemolytic colonies containing bacteria that are oxidase-positive.

c. Small beta-hemolytic colonies containing bacteria that are bacitracin-sensitive.

d. Small alpha-hemolytic colonies containing bacteria that are resistant to optochin.

The colon is the site of the largest number of normal flora bacteria. Which of the following bacteria is found in the greatest number in the colon?

a. Bacteroides fragilis

b. Escherichia coli

c. Clostridium perfringens

d. Lactobacillus species

e. Enterococcus faecalis

Which of the following causes both skin lesions and severe pneumonia?

a. Listeria monocytogenes

b. Clostridium botulinum

c. Bacillus anthracis

d. Corynebacterium diphtheriae

Your patient has subacute bacterial endocarditis caused by a member of the viridans group of streptococci. Which of the following sites is MOST likely the source of the organism?

a. Skin

b. Urethra

c. Oropharynx

d. Colon

Which of the following illnesses is NOT a zoonosis?

a. Q fever

b. Rocky Mountain spotted fever

c. Tularemia

d. Typhoid Fever

Your patient is a 30-year-old woman with a previous history of rheumatic fever who has had a fever for the past two weeks. On examination, you find a new heart murmur. You suspect endocarditis and do a blood culture, which grows a viridans group streptococcus later identified as S. sanguinis. Using your knowledge of normal flora, what is the most likely source of this organism?

a. Vagina

b. Throat

c. Urethra

d. Duodenum

e. Skin

Name the organism(s) most commonly associated with cellulitis.

a. Staphylococcus aureus

b. Propionibacterium acnes

c. Streptococcus pyogenes

d. Both A and B

e. Both A and C

An outbreak of sepsis caused by Staphylococcus aureus has occurred in the newborn nursery. You are called upon to investigate. According to your knowledge of the normal flora, what is the MOST likely source of the organism?

a. Vagina

b. Nose

c. Colon

d. Throat