micro lecture 3

ever wonder how many diseases there are? as of 2003 or so, about 1450 different species of human pathogen were known, which many of them having a wide variety of "strains" or varieties. 60% of them can be contracted from animals, while the remaining 40% are associated only with humans

• King (kilo)
• Henry (hecto)
• Drinks (deca)
• Ulcky (base units: meter liter gram)
• Dark (deci)
• Chocolate (centi)
• Milk (mili)
• (six hops from base to get to:)
• Micro (10e-6)
• (nine hops from base to get to:)
• Nano (10e-9)

a specimen is magnified as light passes thru the objective and ocular lenses

• total magnification is calculated by multiplying the magnification of the objective lens by the magnification of the ocular lens (10x)
• resolution is the ability of the lenses to distinguish two points

• a bean of electrons, instead of light, is used with an electron microscope
• electromagnets, instead of glass lenses, control focus, illumination, and magnification
• thin sections of organisms can be seen in an electron micrograph produced using a transmission electron microscope
• three-dimensional views of the surfaces of whole microorganisms can be obtained with a scanning electron microscope

• acidic dye: the chemical used is negatively charged (staining the background..not often used)
• Basic dye: positively charged chemical is used to stain

• simple stain: use of a single basic dye
• -a mordant may be used to hold the stain or coat the specimen to enlarge it
• differential stain: uses two diferent colored dyes
• -ex: gram stain
• special stains: emphasizes certain cell parts
• -ex: capsule stain

• first step use sthe first stain crystal violent (stains everything purple)
• than add the mordant (grams iodine) to help the chemical reaction along
• than wash with alcohol to decolorize anything that isn't chemically bonding
• than use the last stain: safranin (counterstaining)

• 
• the gram pos bacteria retain the purple stain after the decolorization step
• gram neg bacteria do not and thus appear pink from the counterstain

it only stains one certain genus of bacteria; the micro bacteria because they have acid alcohol outside their cell walls

• acid-fast microbes, such as members of the genera Mycobacterium and Nocardio, retain carbolfuchsin after acid-alcohol decolorization and appear red
• non-acid fast microbes take up the methylene blue counterstain and appear blue

to stain capsule, endospores or flagella to make them bigger to see

• derived from Latin "to know"
• science is a way of asking and answering questions
• it seeks answers to question about natural phenomena
• scientific thinking reduces emotional reactions

• 1. observe an event
• 2. develop a model (or hypothesis) which makes a prediction
• 3. test the prediction (experiment)
• 4. observe the result
• 5. analyze the data
• 6. make a conclusion

• scientific theory: a description of the world that covers a relatively large number of phenomena and has met many observation and experimental tests
• law of nature: theory (or group of theories) that has been tested extensively and seems to apply everywhere in the universe

• bar graphs are used to show a comparison of multiple objects
• pie graphs are used to compare the parts of a whole
• line graphs are used to show the relationship between variables

has multiple lenses and uses visible light

"eye". on a microscope it means the eye piece you look thru

magnifies the object.. has four powers; 4x, 10x, 40x, 1000x

is calculated by multiplying the magnification of the objective lens by the magnification of the ocular lens (10x)

the ability to see two separate things as separate

coloring a microorganism with a dye to make some structures more visible

uses heat or alcohol to kill and attach microorganisms to a slide

a thin film of material used for microscopic examiniation

the chemical used is positively charged

the chemical used is negatively charged (staining the background..not often used)

simple stain: use of a single basic dye

• -a mordant may be used to hold the stain or coat the specimen to enlarge it
• (gram iodine)

• the gram stain classifies bacteria into gram-positive and gram negative
• gram-positive bacteria tend to be killed by penicillin and detergents
• gram-negative bacteria are more resistant to antibiotics

• uses two different color dyes
• ex: gram stain and acid-fast stain
• they differentiate bacteria according to their reactions to the stains

gram-negative bacteria are more resistant to antibiotics

gram-positive bacteria tend to be killed by penicillin and detergents

An additional dye used in a microscopy specimen to produce a contrasting background or to make clearer the distinction between different kinds of tissue.

an agent that removes color, bleaches.

• negative staining is used to make microbial capsules visible
• the endospore stain and flagella stain are special stains that color only certain parts of bacteria

• educated guess
• is testable and falsifiable
• in science hypothesis are tested by using them to make predictions about the outcome of an experiment

something that a lot of people tested and no one as proved wrong yet

• more reliable for obtaining info
• you can test what you believe to be true
• others can repeat your experiment
• opportunity to prove false
• follows general set of systematic procedures
• steps are followed in order to answer a research question

condition or even under study (choose 1) [the collar]

condition that could change under the influence of the independent variable (measure this) [the number of fleas]

• factors throught to be true for the investigation but have not been verified or controlled
• commonly accepted info
• thought to be held constant but not controlled
• factors beyond the investigators control bc of technical or time considerations