LAB 2 MICROSCOPIC EX OF MICRO

Question 1

Movement caused by the bombardment of the molecules present on the suspending liquid towards the organisms

Answer 1

BROWNIAN MOVEMENT

Question 2

Move,ent of organisms by the use or locomotory organelles and/or by gliding motion

Answer 2

true motility

Question 3

thread-like projections that extends from the cell wall

Answer 3

flagella

Question 4

filaments inside their bodies that helps them move

Answer 4

endoflagella

Question 5

creep along a solid surface by any of several possible mechanisms

Answer 5

gliding

Question 6

• it can be made rapidly by SIMPLY placing a small drop of the sample on the clean slide and cover it with a COVERSLIP
• useful in short term observation because it can DRY OUT faster due to the heat from the light of the microscope
  -it is better in OBSERVING smaller microbes such as bacteria than hanging drop

Answer 6

wet mount preparati

Question 7

• useful in long term observation because it allows the organisms to live longer
• stays hydrated due to the petroleum jelly
• better in observing larger microbes

Answer 7

hanging drop method

Question 8

difference between wet mount and hanging drop

Answer 8

wet mount slows down because the slide dries due to the heat and it’s microorganisms movement is limited because they are pressed in between the flat surface. while hanging drop is constant because of the petroleum jelly and because the microorganisms can move freely which provides them space to move.

Question 9

why should we stain bacteria

Answer 9

Bacteria have nearly the same refractive index as water,

therefore, when they are observed under a microscope, they are
opaque or nearly invisible to the naked eye.
Different types of staining methods are used to make the cells
and their internal structures more visible under the light microscope.

Gram staining is an example of staining procedure commonly
used in studying bacteria. This, and other staining procedure begins
with preparation of a bacterial smear

Question 10

specimen from solid media ~ 1 drop or 2 loops full of NSS on center of sterile glass slide&raquo_space; SMALL AMOUNT OF COLONY MIXED WITH NSS

Answer 10

emulsification

Question 11

using an applicator stick or sterile swap ~ specimen applied directly on the glass slide in direct or zigzag manner THROUGHOUT THE SLIDE (ex: vaginal discharge)

Answer 11

streaking

Question 12

a sample of the material placed on a sterile glass slide&raquo_space; GENTLY TEASE THE MUCUS STRANDS APART using an applicator stick (ex: mucopurulent material)

Answer 12

spreading

Question 13

Needs two glass slides ~ a drop of specimen on one slide&raquo_space; THE TWO SLIDES ARE PULLED APART in an uninterrupted motion (ex: blood smear, bone marrow)

Answer 13

pull-apart

Question 14

needs two glass slide ~ place a drop of blood on one end of slide&raquo_space; DISPERSE SPECIMEN USING THE SPREADER SLIDE (ex: blood spec)

Answer 14

wedge-type “film”

Question 15

TOUCH THE TISSUE OR SPECIMEN USING THE GLASS SLIDE (this allows the cell to transfer directly to the slide) ex: urethral discharge

Answer 15

touch preparation or impression smear

Question 16

a small part of sputum is SMEARED on 1/3 of a slide IN A LOOPING MANNER UNTIL FULLY DRIED (acid fast smears)

Answer 16

looping out

Question 17

• is a substance that ADHERES to a cell, giving the cell color
• the presence of color gives the cells significant contrast so are much more visible
• DYES ARE USED IN STAINING METHOD

Answer 17

stain

Question 18

• gram staining is developed by and named after the danish bacteriologist _________ in 1884
• used to classify bacteria on their FORMS, SIZES,CELLULAR MORPHOLOGIST AND GRAM REACTIONS
• it is almost always the first test performed for the identification of bacteria

Answer 18

hans christian gram

Question 19

importance of gram staining

Answer 19

gram stains can quickly and easily reveal both the shape (cell morphology) of the bacterium and whether it is gram positive or gram negative, clinically gram stain results allow for rapid intervention with appropriate antibiotics

Question 20

primary stain

Answer 20

crystal violet

Question 21

mordant

Answer 21

gram’s iodine

Question 22

UPPER TO LOWER OF GRAM STAINING STEPS

Answer 22

1. fixation
2. crystal violet
3. iodine treatment
4. decolorization
5. counter stain safranin

Question 23

this dye will react to the thick peptidoglycan layer of gram positive bacteria, this dye is water soluble

Answer 23

primary stain

Question 24

gram’s iodine causes crystal violet to clump together, or to precipitate in a layer of the cell wall. the function of the _____ is to CAUSE THE PRIMARY STAIN TO ATTACH BETTER OR TO INCREASE THE AFFINITY of stain for a biological specimen, so the specimen is not removed during decolorization

Answer 24

mordant

Question 25

this will dehydrate the peptidoglycan layer, shrinking and tightening it. the crystal violet-iodine complex cannot penetrate this tightened pepti layer and thus TRAPPED in the cell in gram positive bacteria

Answer 25

acetone alcohol (ethanol)

Question 26

• a dye that is weakly water soluble
• is applied which stains the colorless gram negative cells PINK. it does not affect the appearance of the gram positive cells as the have heavily stained with the more intense crystal violet.

Answer 26

counterstain