Chapter 3 Microscopy And Staining

Question 1

Be able to identify the various types of bacteria morphologies give him an image or diagram of bacteria.

Answer 1

Morphology is equal to the shape of a single cell

Question 2

Coccus

Answer 2

Sphere

Question 3

Bacillus

Answer 3

Rod

Question 4

Spirochete

Answer 4

Elongated helix

Question 5

Vibrio

Answer 5

Comma

Question 6

Coccobacillus

Answer 6

Sphere and rod combined

*annoying

Question 7

Identify arrangements of bacterial cells given an image or diagram of bacteria

Answer 7

Arrangements are equal to the how cells are grouped together

Question 8

Strepto

Answer 8

Long chain

Question 9

Staphylo

Answer 9

Irregular clumps

Question 10

Streptobacillus

Answer 10

Rods in a chain

Question 11

Streptococcus

Answer 11

Spheres in chain

Question 12

Staphylococcus

Answer 12

Clumps of spheres

Question 13

Diplococcus / diplobacillus

Answer 13

2 spheres

2 rods

Question 14

Tetrads

Answer 14

4 spheres in a square

Question 15

Know the basic unit of measurement commonly used to measure cell size

Answer 15

Micrometer 1/1,00,000 of a meter a.k.a. micron

Nanometer 1,000,000,000 of a meter

Atoms are a fraction of nanometer in size

Question 16

Describe the parts and functions of the parts of a compound light microscope and be able to diagram the right path of a compound microscope

Answer 16

Parts From bottom to top
Light source,
condenser,
objective lens with variable magnification ocular lens 10x magnification

Light path from bottom to top
Light source 
condenser
specimen slide 
objective lens

Question 17

Explain the purpose of immersion oil and why permits observation of bacteria 1000x magnification or higher

Answer 17

The light is not lost in oil is in the gap

hire magnification smaller field of view less light

Question 18

Know the limitations of light microscopy.

Recognize the approximate resolution limit for light microscope’s

Answer 18

Light microscope’s 2000 x
10micrometers

Electron microscope 10,000,000 x mag
2 micrometers

Question 19

Describe the protocol for heat fixing bacteria on a slide and no the reasons why he fixing is done

Answer 19

Aseptic technique 
smear 
Heat fix 
-Adheres bacteria to slide
-Kills bacteria (useful)
-Makes bacteria receptive to dyes
stain

Question 20

State the chemical difference between basic an acidic dies

Answer 20

Basic dyes: positively charged
cation. Bacteria and negatively charged therefore a very attracted to basic dyes

Examples: methylene blue crystal violet Malachi green safranin

Acidic dyes: Negatively charged anions
Dye has the same charge as most cells negative staining the day is excluded from the seller leaving colorless against stain background. Good for morphology

Examples: eosin nigrosin

Question 21

What is the function of a mordant

Answer 21

Chemicals that intensify the appearance of the dye by improving binding or trapping the dye

Question 22

Which type of staining is the Gram stain? What about the acid fast stain?

Answer 22

Differential stains

Question 23

If I apply methylene blue to bacteria that has been heat fixed to slide and wash off the dye, add a drop of emotion oil, and observe, what Stan do I have

Answer 23

Simple stain

Question 24

What genre are identified using the acid fast stain

Answer 24

Used to identify genre mycobacterium, nocardia, Mycobacterium tuberculosis, microbacterium leprae

These contain sturdy cell wall containing my colic acid, wax is, complex lipids

Acid-fast means they keep the stain even when treated with acid

Question 25

Given an image of an acid fast stain, Identify the bacteria that are acid-fast

Answer 25

Primary stain Carbolfusion red

Counterstain methylene blue

Acid fast bacteria are red

Question 26

Given an image of mixed culture that has been Graham stained,The able to identify which bacteria or gram-positive and which are Graham negative

Answer 26

Bacteria that retain crystal violet are gram-positive purple

bacteria that Are red and did not retain crystal violet a gram negative

the reason why the gram-positive bacteria appear Purple and not Red is due to the retention of crystal violet

counterstain allows visualization of the non-gram-positive cells

*Gram-positive bacteria do not decolorize Graham negative do