lab microscopy

combined with

a 10X objective, these create total magnifications of 40X, 100X, 400X, and 1000X

resoultion

ability of a lens to distinguish closey placed points or fine details

condenser lens

beneath the stage focuses light on the specimen

a third lense

called the condenser, is located under the stage.

contrast

diffrence inbirghtness or color between an object and its background

rotating nose piece

disk which turns to change objectives

working distance

distance ( in mm) between the tip of the objective an dthe civerslip when the object is in sharp focus

condenser lense

does NOT magnify the image. It concentrates the light into a cone as it passes through the specimen to help produce the clearest image possible

Transmission electron microscopes (TEMs)

focus a beam of electrons through a specimen are used mainly to study the internal structure of cells

mechanical stage

holds a slide snuggly on the stage;knobs change the slide potion on the stage

100x

is designed to be used only when a drop of oil fills the air space between the slide and this objective THUS IS called OIL IMMERSION OBJECTIVE

feild of view

is the area of the specimen that can be seen in the microscope. As magnification increases, the field of view gets proportionally smaller .For example, if the field of view is 5 mm in diameter at 40X, it will have a diameter 2 mm of at 100X.

coarse adjustment knob

large knob on the lower arm used to achieve inital focus

condenser

lens below the stage that produces a cone of light to illuminate the object;notes the knob which raises and lowers the condenser to adjust the brightness of the field

Parfocal

lens that stays in focus when magnification/focal length is changed

irris diaphragm

located below the condenser;regulates brightness by increasing or decreasing the amount of light entering the condenser

the 10x objective is called the

low power objective

Base

lower portion of the microscope that supports the instrument

the use of microscope is called

microscopy

objective lens

mounted rotating nosepiece just above the stage, collect light from the specimen and forms an enlarged, inverted image called REAL IMAAGE

the real image produced by onjective lens is futher enlarged by the

oculars or eyepeices

total magnification

of a microscope is the product of the objective lens magnification and the ocular lens magnification. (multiply them together)

ocular lens

produces a virtual image and magnifies the image

total magnifciation

product of the magniifcation of the objective and magnification of the ocular

lamp

provides light to illuminate the object

40x

provides the greatest magnification without oil and is called the HIGH POWER

stage

rectangular surface on which a slide is place for examinantion

The magnification of a microscope is changed by

rotating in different objective lenses.

the 4x objective is called the ___________

scanning objective because it is used primary to locate an object on the microscope slide,

Simple Mircoscope

single lens first one ( VON LEEWENHOEK Late 1600;s); it had: focusc knob, lens, sample holder, sample translator

fine adjustment knob

small knob on the. lower arm used to bring the object into sharp focus

All prokaryotes are unicellular organisms, but many prokaryotes grow in groups rather than lone cells

staphylo - clusters of cells- strepto - chains of cells

Fluorescence microscopy: cytoskeletal structure in animal cells

Green emitting fluorophore labels microtubules (tubulin) Red emitting fluorophore labels microfilaments (actin) Blue emitting fluorophore labels DNA

resoultion

the measure of the clarity of the image, or the minimum distance of two distinguishable points can be defined as either: diameter of smallest visible object or shortest distance at which 2 objects can be distinguished Smaller values of resolution are better than larger values is essentially the clarity or amount of detail in an image.

Magnification

the ratio of an object's image size to its real size how many times bigger the image is compared to the object Light microscopes typically use magnification between 2X - 2,000X Most microscopes in biology labs use magnifications of 40X, 100X, 400X and 1000X

a compound microscope

two magnifying lenses: Results in more efficient magnification utilizing smaller lenses• Total magnification = ocular mag. X objective mag. example: janssen compund ( late 1600) powell& lealnad no1 (1850)

object less than 0.1 mm in diameter are undistinusgished by

unaided human eye

arm

vertical bar used to grasp and carry the mircoscope

dept of focus

vertical dimesnion (depth( of teh specimen in fous using a particular objective

the oculars produce a

virtual image

contrast

visible differences in parts of the sample ability to distinguish an object from its background improved by special types of microscopy and staining

fluorscence

when a light-absorbing molecule called a fluorophore absorbs one color of light and emits a different color

Most light microscopes are equipped with

4X, 10X, 40X and 100X objective lenses.

objective lens

4x,10x,40xx or 100x lens producing a real image; mounted on the rotating noseplate

two lenses magnify the image in a compound microscope:

A binocular microscope has two ocular lenses, one for each eye the ocular lens (eyepiece) and the objective lens.

depth of focus

As magnification increases, the depth of focus decreases depth of focus decreases as magnification increase therefore, always begin focusing with the lowest power objective.

Scanning electron microscopes (SEMs

) focus a beam of electrons onto the surface of a specimen, providing images that look 3-DElectron Microscopy

plane or focus

Only a "slice" of the specimen

your objective lenses are

PARFOCAL

compound mircoscope

(4x, 10 X, 40x,100x)

Prokaryotic cells are typically either spherical or rod-shaped

- cocci - spherical cells- bacilli - rod-shaped cells

How to focus a light microscope

1. Make sure the light is not too bright 2. Make sure lowest power objective is in place 3. Raise the stage all the way up using the course focus knob 4. Look through the eyepiece and slowly lower the stage using the course focus knob until the specimen is mostly in focus 5. Use the fine focus knob to adjust to perfect focus

A three lens system produces that images seen through the microscope

1. the condenser 2. objective kens 3. ocular lens

The ocular lens typically magnifies

10x

stains

Biomolecules such as proteins and nucleic acids are typically negatively charged and will bind to cationic dyes

Limitations of Light Microscopy

The resolution of light microscopes is limited by the wavelengths of light. • Light microscopes can resolve objects down to about 200 nm in size

Fluorescence Microscopy

The specimen is labeled by fluorophores designed to target specific molecules and cellular structures•The microscope uses a laser to excite the fluorophore, and the emitted light is observed using a filter that blocks out the light from the laser •Multiple fluorophores can be used simultaneously

depth of focus (or focal depth)

The thickness of the plane of focus is

types of microscopes

Types of microscopes• Light microscope: simple, compound, fluorescence Electron microscopes: TEM, SEM

electron mirscope

Uses streams of accelerated electrons rather than light• Electrons are focused by magnets rather than glass lenses• Can resolve structures down to 0.5 nm• Scanning Electron Microscope (SEM)• transmission Electron Microscope (TEM)