Lecture 2

Question 1

Linnaeus

Answer 1

-Scientific nomenclature
*Italicized or underlined

Question 2

Discoverer of Escherichia Coli (E. coli)

Answer 2

Theodor Escherich

Question 3

Staphylococcus aureus name breakdown

Answer 3

Clustered (staphylo-)
Spherical (cocci)
Gold-colored (aureus) colonies

Question 4

Simple microscope

Answer 4

-Has only one lens
-Invented by Van Leeuwenhoek

Question 5

Compound light microscopy

Answer 5

-2 lens
-Total magnification=objective lens x ocular lens

Question 6

Compound light microscopy

Answer 6

-Magnification
-Resolution: ability of the lenses to distinguish fine detail and structure
•resolving power of 0.45 um can distinguish between two points if they are at least 0.45 um apart

Question 7

Light microscopy

Answer 7

-microscope that uses visible light to observe specimens
-types of compound light microscopy
•Brightfield
•Darkfield
•Phase-contrast
•Differential interference contrast
•Fluorescence
•Confocal

Question 8

Phase-contrast Microscopy

Answer 8

-Accentuates diffraction of the light passes through a specimen
-Best way to view bacteria in natural state

Question 9

Fluorescence Microscopy

Answer 9

-Cells may be stained with fluorescent dyes (fluorophores)
-The specimen is illuminated (excited) with light of a specific wavelength

Question 10

Green fluorescent protein GFP

Answer 10

Found in Aequares Victoria jellyfish

Question 11

How fluorophores are used

Answer 11

-Cloned into a gene—expressed as a protein

Question 12

Electron microscopy

Answer 12

-1931
-electrons instead of light
-Highest magnification (100,000-300,000x) & greatest resolution
-visualize viruses and organelles

Question 13

How to visualize bacteria

Answer 13

-Wet mount
-Smear
-Fixation
-Staining

Question 14

Smears for staining

Answer 14

-Basic dye, the chromophore is a cation
-Acidic dye, the chromophore is an anion

Question 15

Simple stains

Answer 15

-Positive/Direct stain: Dye applied to the cells
•basic
-Negative/Indirect stain: Dye applied to the background/slide
•acidic

Question 16

Differential Stains (what)

Answer 16

Two or more dyes used to distinguish between bacteria
-gram stain
-acid-fast stain

Question 17

Gram stain steps

Answer 17

1. Fixation
2. Crystal violet
3. Iodine treatment
4. Decolorization
   -gram negative loses color
5. Counter stain (safranin)
   -gram pos=purple
   -gram neg=pink

Question 18

Prokaryotic cell size

Answer 18

Range: 0.2 um- >700um diameter

Question 19

Eukaryotic cell size

Answer 19

Range: 10- >200um diameter

Question 20

Advantages of being small

Answer 20

-small cells have high S/V (surface area to volume ratio)
-Support greater nutrient exchange per unit cell volume
-tend to grow faster than larger cells

Question 21

Advantages of Large cell size

Answer 21

Upper size limit is set by rates of diffusion for import and intracellular transport

Question 22

Prokaryote cell basic shapes

Answer 22

-Bacillus (rod-shaped)
-Coccus (spherical)
-Spirillum (spiral)
•Spirillum
•Vibrio
•Spirochete

Question 23

Prokaryote cell shape facts

Answer 23

-Most bacteria are monomorphic (have one shape)
-a few are pleonorphic (change shape)

Question 24

Prokaryotic cells: unusually shaped bacteria

Answer 24

-Star-shaped bacteria
-Rectangular bacteria

Question 25

Prokaryotic cell arrangements

Answer 25

Pairs: diplo-
Clusters: Staphylo-
Chains: Strepto-
Branched: Streptomycetes