# Under which of the following conditions would you be most likely to prepare (and use) a smear?

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1.

Smear is prepared to visualize the cell under microscope. Smear makes a single layer of cells so that it can be seen easily after staining them.

To study if the bacteria can breakdown a perticular nutrient we can use selective or differential media which is provided with indicator. If the bacteria will breakdown the perticular substance, the color of the media gets changed. We don't need to make smear.

Isolation of individual bacterial species from mixed culture is done by picking up the colony from agar plate and re-inoculating it on new plate by zig-zag spreading and this is done 2 to 3 times, so that the new colony generated will be kind of pure colony, i.e., made of same type of bacterial species.

In transferring bacteria from broth culture to slant tube, a loop full bacteria is taken with a sterile inuculating loop and is gently spread onto the surface of the slant.

So, option a) is correct.

2.

Steps for preparation of broth culture are:

• clean the LAF and sterilize with 75% EtOH
• clean the glass slide
• inoculating loop is heated till it becomes red (sterilization) and is cooled
• cap of the culture tube is removed and the opening of the tube is flamed for sterilization purpose
• a loopful of broth is taken from the culture tube and kept on slide
• some water droplets are added and is spread on the slide
• air dry the slide
• pass the slide through flame 2 to 3 times.

So, the correct option is e) is correct.

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