BIOL229: Lab Final

total magnification

objective lens magnification x ocular lens magnification

field of view

what you can see through the oculars at a given magnification

does increasing magnification increase or decrease the field of view?

decrease

working distance

space between objective lens and slide

coarse focus knob

moves stage large distances; only used on scanning lens

fine focus knob

used to bring an object back into focus after switching magnification

parfocalization

being able to switch magnification after focusing on an object and still remain nearly in focus

refraction

when light passes through a medium into another, light rays often bend

immersion oil

used with 1000x objective because the oil has same index of refraction as glass; improves resolution

prokaryotic cells

very simple and lack a nucleus or membrane bound organelles and are small in size

eukaryotic cells

more complicated; contain a nucleus and many specialized organelles

1

ocular eyepiece

2

observation tube

3

arm

4

coarse focus knob

5

fine focus knob

6

stage control knob

7

base

8

light source

9

condenser lens

10

iris diaphragm

11

stage

12

stage clip

13

objective lens

14

nosepiece

flea

*note hooks

tapeworm scolex

Schistosoma adult worm

Schistosoma cercariae

Giardia trophozoites

“smiley face” - 2 nuclei

trophozoites

*note flagella, nucleus

Trichomonas vaginalis

*note red blood cells, parasite, nucleus, flagella

Trypanosoma

Penicillium

little circles/dots

conidia (spores)

Aspergillus

little circles/dots

conidia (spores)

Rhizopus sporangia

Rhizopus zygospore

Peziza

area surrounding red dots

ascus

red dots

Ascospores

*note budding cells

Saccharomyces

Schizosaccharomyces

*note gills

Coprinus

red dots

basidiospores

Physicia lichen

small pink

erythrocytes

purple

leukocyte

*note cilia

Balantidium coli

*note oral groove, nucleus, cilia (if visible)

Paramecium

*note nucleus, pseudopodia

Amoeba

blue arrow

contractile vacuole

Radiolarians

Spirogyra

spirals inside

spiral chloroplast

Volvox

Chlamydomonas

Diatoms

*note flagella, nucleus

euglena

normal flora

organisms that naturally reside on our skin; remain even after washing/disinfecting hands

degerming

mechanical action of removing microbes

aseptic technique

a way of working that reduces the chance of contamination by microbes

bunsen burner

used to heat-sterilize metal objects; hot air rises, creating convection current, creating sterile field around burner

incinerator

used to heat-sterilize metals while preventing aerosols

cofluency

growth that merges together to cover a surface; prevented through quad streaks (streak plates)

spectrophotometer

determines the absorbance of a bacterial culture; sends specific wavelength of light through a sample and a detector will read the amount of light that came through

serial dilutions (know how to calculate)

obtained by making a dilution, mixing then removing some of that material and diluting it in a new volume (repeated as needed)

direct methods of counting bacteria

microscopic counts, dilution plating and most probable number determinations

indirect methods of counting bacteria

biochemical readings and optical densities

1

spirillum

2

coccus

3

bacillus

Nostoc

Oscillatoria

type of flagella

amphitrichous flagella

Spirilllum volutans

type of flagella

peritrichous flagella

Proteus vulgaris

cluster of flagella on one side of bacteria

lophotrichous flagella

one flagella on one end of bacteria

monotrichous flagella

Spirochetes

Klebiella pneumoniae

chromophore

the colored molecule responsible for the visual of the stain

acidic dye

give off H+ and the chromophore is negatively charged; repelled by cellular structures so the background in stained

basic dye

gives off OH- and the chromophore is positively charged; attracted to cellular structures and stains the cell

smear

process of preparing a slide for a stain involving basic dyes; precedes simple, gram, endospore, and acid fast staining

heat fix

process of applying heat to a slide in order to kill the organisms and cause them to adhere well to the glass slide

bibulous paper

the absorbent paper used to blot excess water from slide before viewing

what dye did we use for the simple stain?

methylene blue

what is a simple stain?

a staining procedure that uses one (basic) dye

what is a negative stain?

stains the background with a negatively charged chromophore (acidic dye); negatively charged pigment is repelled from similarly charged bacterial cell

what dye did we use for negative stain?

nigrosin (india ink also works)

what is a capsule stain?

combination of a negative stain followed by a basic dye; there is no heat fix (to avoid shrinking organism)

differential stains

use more than one dye and are capable of revealing structure or characteristics of the stained cells

what is a gram stain?

offers insight into the type of cell envelope of your specimen; differentiates gram positive and gram negative bacteria

gram positive bacteria

have a thick cell wall (~20-80nm) located external to plasma membrane; wall is make of peptidoglycan

gram negative bacteria

have thinner cell wall (~10nm); have an additional outer membrane layer external to cell wall; primarily made of lipopolysaccharides (LPS) and membrane proteins

what is the primary stain in gram stains?

crystal violet; step 1, positively charged (basic) dye, interacts with gram positive and negative bacteria

what is the mordant in gram stains?

gram’s iodine; reacts with crystal violet to form iodine-crystal violet complex (I-CV complex) which stains peptidoglycan layer (harder to remove from gram positive)