Question

1. In a tube of Thioglycollate broth, _ would grow at the very top portion of the tube while ___ would grow throughout the tube.

B. Obligate anaerobes, obligate aerobes

C. Microaerophiles, facultative anaerobes

D. Obligate aerobes, facultative anaerobes

2. Which of the following does acheive sterilization?

A. freezing

B. boiling

C, ethylene oxide

D. none of the above

3. All of the following are modes of action of antiviral drugs except __

A. inhibition of peptidoglycan synthesis

b. inhibition of DNA or RNA synthesis

C. inhibition of fusion

d. inhibition of uncoating

4. The beta-lactams affect the crosslinking between NAM subunits. How are we able to use these drugs against bacteria and not do significant harm to our own cells?

a. Human cells use 80S ribosomes, while bacteria use 70S ribosomes.

b. Human cells do not possess peptidoglycan.

c. Human cells have different cell membranes than bacteria.

5. Tamiflu works against the influenza virus by blocking the action of neuraminidase, thereby blocking ____ of the virus.

A. attachment

b. biosynthesis

c. release

6. Mary is put on antibiotic treatment for an infection. After a week, she develops thrush, a yeast infection on the tongue. This represents which of the following?

A. synergism

b. superinfection

c. double whammy syndrome

7.  Which letter represents the phase of the growth curve where the maximum population density is the greatest? Choose the answer that has BOTH the letter and the description correct.

1 A: lag phase

3. C: stationary phase

4. B. stationary phase

Answer 1

1)D

Thioglycollate broth contains high concentration of oxygen at top and low oxygen concentration gradient at bottom.So,the organisms like oxygen( aerobes) grow in clusters at the top.And the organisms that don't like Oxygen(anaerobes) grow at bottom.

2)C

Ethylene oxide at lower temperature used as sterlizer.Ethylene oxide is used for the sterlization of that type of instruments that are not able to withstand at higher temperature.Eg: endoscopes.

3)A. Antibiotics inhibit peptidoglycans synthesis because , bacterial cell wall is made up of peptidoglycans.so,antibiral drug don't act on peptidogylcan.

4.B. Beta lactum antibiotics prevent peptidogylcan synthesis ( bacterial cell wall is made ) .Human cell don't contain peptidogylcan .so, antibiotics will not cause any harm to human cell .

5) C) Tamiflu block action of neuraminidase( this enzyme cause release of virus from infected cell to healthy cell).Due to blocking of neuraminidase virus will not release from infected cell.

6) B)

some antibiotics will cause superinfection ( after earlier infection). Antibiotics suppress normal flora.

7) log phase( exponential phase ) show high growth rate , stationary phase show Equal growth rate and death rate .