Question

65. An inoculated thioglycolate medium culture tube shows dense growth at the surface and turbidity throughout the rest of the tube. What is your conclusion?                                                                 

A. The organisms die in the presence of oxygen                                                                                                  

B. The organisms are facultative anaerobes.                                                                                                       

C. The organisms should be grown in an anaerobic chamber.                                                                              

D. The organisms are obligate aerobes.                                                                      

66. A scientist develops a new medication that is a protein compound and that must be administered by injection. Which of the following would be the most effective and safest means of preparing a sterile solution of the new medication?                                                                                         

A. Filtration                                   

B. Autoclaving                     

C. Lyophilization

D. Dilution with alcohol                   

E. Ultraviolet irradiation

67. Which of the following is NOT used to visualize live cells?                                                                                                                                        

  A. Phase contrast microscope                                        

B. Transmission electron microscope                                                                                                                                             

C. Dark field microscope                                                  

D. Compound light microscope                                                               

Answer 1

1) The correct option is b. Facultative anaerobes

facultative anaerobes are the organisms which respires aerobically in the presence of oxygen and in absences of oxygen they shift to fermentation.

In thioglycolate media culture tube the oxygen tension present at the surface is more , so the organisms respire aerobically at the surface hence show dense growth there and where the oxygen is absent they switch to fermentation so growth is less here.

2) The correct option is A.

Filtration is effective and safest method to isolate Sterile solution of the new medication. Filtration doesn't destroy the protein structure and also makes it sterile.

67) the correct option is b. Transmission electron microscope.

Transmission Electron microscope is most powerful microscope it is used to generate high resolution images of the sample ,even of an electron. But cannot used in living samples because it involves firing of electrons through the sample which destroys the live cells.