MICROBIOL ad EMMUNOL LAB I. Ithe objective lenses of a micosoope cas be witched
ID: 206183 • Letter: M
Question
MICROBIOL ad EMMUNOL LAB I. Ithe objective lenses of a micosoope cas be witched from one to anober without losing focus on t D optifocal electron C floresceace B. electron C bright-field O dark-feld 4,hior to "tai ing, =ears of.wronganna rth tandinceder to A. allow eventual visalization of internal stractures Benare removal of dust particles Som the slide saface O attach it finmly to the side D, create smal pores in cells that facilitstes binding of stain to cell atructures 5. If the decolorital is left on too long in the Gram-staining procedare, g-positive orgas will be nd gram-ongative organisms will be staised C purple, pink 0 rink; piek 5. If the decolorizer is ot ledt on long mough in the Gram-staining be stained nd gn-segative organss w will be stained paple purple purple; colodless C purple, pink D pink pinkExplanation / Answer
1. Perfocal microscope. When object stays in focus but lenses can be switched to one another that microscope is perfocal microscope.
2. Phase contrast. Phase contrast microscope can detect sligt change in refractive index.
3.Dark field microscope. In dark field microscope the specimen visualized with bright within a dark background. Useful for visualize motility of small organisms.
4. Heat fix causes to firmly attach of sample to slide.
5. If decolorizer ( alchohol) is left too long gram positive bacteria will be stained purple because when we use mordant ( iodine) it attaches firmly and forms very deep of cell wall . That can not be decolorize fully by alchohol because alchohol is a denaturing agents also and it makes the cell surface dry and also denatures proteins so it stops it own entry to go very deeps and cells remain purple. And gram positive will be stained red.
6. If decolorizer alchohol is not left too long , if alchohol stays a less time than the actual protocol time then the LPS layer of Gram negetive bacteria can't be fully wiped out and gram negetive bacteria will also appear as gram positive.
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