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copperfrog478Lv1

28 Sep 2019

For each of the following statements about the procedure for identifying an unknown bacterial strain, answer True or False.

- Before doing an indole test you should first get a pure culture of the bacterial strain.

- Before doing a catalase test you should first get a pure culture of the bacterial strain.

- Before preparing a stock culture you should first get a pure culture of the bacterial strain.

- Before doing a H2S test you should first get a pure culture of the bacterial strain.

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Casey DurganLv2

28 Sep 2019

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Related questions

1. You smear a small a mount of culture onto a strip containing a reagebt that tests for the presence of oxidase. The inoculated spot turns dark blue within 20 seconds. What does i mean?

a. The culture deos not contain oxidase

b. The culture is likely an aerobe

c. The culture is likely an anaerobe

d. The culture does not contain catalase

E. None of the above

2. True or False

a. The catalase enzyme is found in all obligate aerobes and facultatuve anaerobes to deal eith H2O2

b. An exergonic reaction requires energy input and must be coupledwith ATP hydrolysis in order to proceed

c. The TCA cycle must "turn twice" in order to complete the oxidation of one glucose molecule.

d. Allosteric regulation occurs when an enzyme has a site that can bind an effector molecule seperate from the active site.

e. Some bacteria use desulfurases to produce hydrogen sulfide from he breakdown of some amino acids.

f. A 1/10 dilution can be made by adding 1 mL sample to 10mL diluent

3. You obtain the following results after incubation of a bacterial starin in tge indicated carbohydrate fermemtation sugar media:

Sugar: Color of Medium Durham tube results

Glucose Yellow No bubble

Maltose Red Bubble

Mannitol Yellow No bubble

Lactose Yellow Bubble

Sucrose Red No Bubble

Which sugars cannot be fermented by this bacterial strain?

a. glucose and mannitol

b. maltose and lactose

c. lactose

d. maltose and sucrose

e. none of the choices are correct

copperpug836

For each of the statements about carbohydrate fermentation experiments given below, respond "True" or "False".

If there is no growth in the tube it means the bacterial strain being tested can't ferment that sugar.
All of the species in the family Enterobacteriaceae can ferment sucrose.
Raffinose is a trisaccharide with the formula C₁₈H₃₂O₁₆, it is common in plants.
Bacteria with a fermentative type of metabolism require oxygen (O₂) to make acid from glucose.
Lactose is a disaccharide with the formula C₁₂H₂₂O₁₁, made of a glucose attached to a galactose.

ochremink105

Delia, a five-year-old, woke up one morning complaining that she had a sore throat, headache and stomachache. Her tonsils appeared swollen, and a tonsular exudate, appearing as a cream-colored pus, was evident upon examining the childâs oropharynx. Her mother also took Deliaâs temperature and noted the girl was running a low-grade fever. Suspecting strep throat (streptococcal pharyngitis), her mother made an appointment with the pediatrician.

The doctor first performed a rapid strep test, which works by detecting certain cell surface proteins on group A streptococci (GAS). This test is inexpensive and can detect GAS in a matter of minutes. However, rapid strep tests that come back negative are not especially reliable; about five out of every 100 patients with streptococcal pharyngitis will have a negative rapid strep test result. Therefore, despite Deliaâs rapid strep test being negative, the doctor went ahead and ordered a bacterial culture. This was a wise decision because Delia had signs and symptoms that pointed to a case of streptococcal pharyngitis caused by the Gram-positive, nonmotile, encapsulated prokaryote Streptococcus pyogenes.

When cultures to detect S. pyogenes are performed, the patientâs sample (in this case a swab of the throat) is streaked out onto a specialized nutrient-rich agar called blood agar. Actively growing S. pyogenes can break down red blood cells (a process called beta hemolysis), and, therefore, is readily detectable on blood agar plates because a clear zone develops around its colonies. Based on the microbiology data that came back, Delia was treated for streptococcal pharyngitis. After 48 hours on an antibiotic, Delia felt much better and returned to school.

QUESTION: Would you expect to find endospores if you conducted an endospore stain of the patientâs cultured infectious agent? Explain your reasoning. (Choose the single best answer.)

A. Endospores should be found within the patientâs culture since S. pyogenes makes endospores in response to antibacterial drugs treatments.

B. Endospores should be found within the patientâs culture since S. pyogenes was grown in nutrient-limiting conditions.

C. Endospores should not be detected in the patientâs culture since S. pyogenes is a non-endospore forming pathogen.

D. Endospores should not be detected in the patientâs culture since S. pyogenes was grown under favorable conditions that promote germination.

E. Endospores should not be detected in the patientâs culture since S. pyogenes is Gram-positive, and, therefore, doesnât make endospores.