Question

Name: Match each microscope component with its description or function. 1. Objective _2. Ocular __3. Condenser 4. Diaphragm a. gathers light rays and focuses on object b. eyepiece c. magnifying element located on nosepiece d. disk with an opening that adjusts amount of light that contacts specimen Match each reagent of the Gram stain with its description or purpose. __5. Crystal violet ___6. Gram's iodine ___7. Acid alcohol 8. Safanin a. Secondary or counterstain b. Mordant C. Primary stain d. Decolorizer 9. Gram negative bacteria: a. retain the primary stain and lose the secondary stain b. lose the primary stain and retain the secondary stain C lose both the primary and secondary stain d. retain both the primary and secondary stains 10. A selective agar to isolate stool pathogens, such as Salmonella and Shigella which inhibit normal flora coliforms is: a. Selenite broth b. Hektoen Enteric C. Eosin Methylene Blue d. Modified Thayer Martin

Answer 1

There are parts of microscope matched with its function

1-objective lenses- it magnifying the elements located on nose piece.

A standard microscope has 3,4or 5 lenses which have different range of power from 4x to100x

2-ocular is eyepiece which helps to watch the object

3- condenser- gathers and focus light from illuminator on to specimen being viewed

4- diaphragm- adjust the amount of light that reaches the specimen

The next is about reagent used in gram staining with their action

1-crystal violet- it is a violet coloured primary stain which is used for stain bacteria

2- Gram's iodine - it is a mordant which fix and stabilise the primary stain

3- Acid alcohol- it is used as a decolourizer which faded the colour of primary stain

4 - secondary stain -safranin is used as secondary stain which red in colour

Gram's positive bacteria does not leave its primary stain because of their thick cell wall but Gram's negative leave their primary stain colour and absorbed safranin and gives red appearance