Question

Microblology 208 Summer 2019 Exam 2 1) A thin section of a bacterial Sample is cut with a knife and exposed to an electron beam. during: a) confocal microscopy b) fluorescent microscopy c) section electron microscopy d) scanning electron microscopy e) transmission electron microscopy 2) A bacterial sample is spray-coated with a metallic mixture and subjected to an electron bean during: a) confocal microscopy b) fluorescent microscopy c) surface electron microscopy d) scanning electron microscopy e) transmission electron microscopy 3) Internal structures of a bacteria can be seen with an electron beam during a) darkfield microscopy b) compound microscopy c) section electron microscopy d) scanning electron microscopy e) transmissión electron microscopy 4) Surface features of bacteria can best be seen with: a) confocal microscopy b) fluorescent microscopy c) section electron microscopy ) scanning electron microseopy e) transmission electron microscopy 5) Gram positive cells stain: a) purple b) pink c) red d) black e green

Answer 1

1. e. In transmission electron microscopy , the sample is taken to form an image where the image is formed by transmission of electrons through the specimen or sample. The specimen or sample will be very thin section which is less than 100nm in thickness or the suspension over the grid.

2. E. In my opinion the answer might be transmission electron microscopy because these are used with the help of beam of lights which is capable of increasing the resolution of the image over light microscope. The whole bacteria or the object is coated with gold or palladium which are metals in order to view the 3- D image of the bacteria which is done by creating dark or light images of the organism on the monitor.

3. E. Transmission electron microscopy or TEM is a technique of microscopy in which the beam or the light of the electrons are communicated or transfered through a sample in order to form a proper image .

4. D. Scanning electron microscopy is used to scan the surface of the microorganism because it helps in production of the image of the sample with the help of focused beam electrons. This is done by interaction of electrons with the sample's atoms present.

5.a. The gram positive bacteria have the cell wall which is very thick in texture which will make them to absorb all the stains which makes them turn into purple colour because of the absorption of the crystal violets which are used as dyes.