Processes that sustain life: Types of microscopes

Question 1

Atomic force micoscopy

Answer 1

Magnifications ranges from 1000x to 100000000x. No special preparation or staining is needed. Metal and diamond probe scans surface of the specimen, responding movements of probe are used to produce 3d image in near atomic detail.

Question 2

Fluoresence microscopy

Answer 2

Magnification ranges from 40x to 2000x. Can be used to examine naturally fluorescent specimens or specimens stained with fluorescent dyes. Shines ultraviolet or near ultraviolet radiation on specimens to make them fluoresce.

Question 3

How does a stereo microscope work

Answer 3

Type of light microscope used for studying external structures. Has an ocular and objective lens for each eye and a low magnifying power usually from 6x to 60x. Provide a more 3d image. This image is not reversed and it is often used for dissections that need magnification.

Question 4

How does a scanning electron microscope (SEM) work

Answer 4

Shines a beam of electrons knocking secondary electrons from the specimens surface to produce an image. Images are in 3d. Best for external details of different sized objects. Max resolution of 0.000005mm. Magnification 1000x to 10000x. SPECIMEN ARE FIXED AND COATED WITH GOLD OR CARBON. THE GOLD HOLDS THE SHAPE AND PREVENTS ELECTRONS FROM PASSING THROUGH.

Question 5

How does a transmission electron microscope (TEM) work

Answer 5

Shoots an electron beam through a specimen. Images are in 2d. Works best for examining internal details of small cells. Max magnification of 1 000 000x and a max resolution of 0.0000002mm. SPECIMEN ARE FROZEN OR EMBEDDED IN PLASTIC AND THINLY SLICED

Question 6

How to determine FOV on high power

Answer 6

FOV low power, mutliplied by magnification low, divided by magnification of high

Question 7

How to determine FOV on medium power

Answer 7

FOV low power, multiplied by magnification of low, divided by magnification of medium

Question 8

How to determine FOV on a low power

Answer 8

Measure with a ruler and convert to micrometers (1milimeter is 1000 micrometers)

Question 9

What is formula for estimating the cell size

Answer 9

Diameter of the field of view divided by the number of cells that fit across the diameter

Question 10

Light source function

Answer 10

Directs light through the diaphragm, the specimen and the lenses. Some microscopes have a mirror, if so the mirror must reflect light at the correct angle from the source. Caution, do not use sunlight as the light source

Question 11

Base function

Answer 11

Provides support for the microscope

Question 12

Diaphragm function

Answer 12

Controls the amount of light entering the body tube

Question 13

Condenser lens function

Answer 13

Directs light to the object being viewed

Question 14

Fine adjustment knob Function

Answer 14

Sharpens the image under medium and high power, primarily high power

Question 15

Coarse adjustment knob function

Answer 15

Focuses the image under low power

Question 16

Stage clips function

Answer 16

Holds the microscope slide in place

Question 17

Stage function

Answer 17

Platform which supports the microscope slide

Question 18

Revolving nosepiece function

Answer 18

Holds/turns the objective lenses into viewing positions

Question 19

Objective lenses function

Answer 19

Each contains a lens with a different power of magnification, such as 4x 10x or 40x engraved on the objective. These are referred to as high low and medium power

Question 20

Microscope arm function

Answer 20

Supports the body tube, carry the microscope with the arm

Question 21

Eyepiece function

Answer 21

Contains a magnifying lens you look through, magnifying power is usually engraved besides the lens

Question 22

Body tubes function

Answer 22

Holds the eyepiece at the proper distance from the objective lenses

Question 23

When using a compound microscope what should you keep in mind

Answer 23

-as magnification increases the field of view decreases, making finding specimens under lower magnification easier
-as you switch powers always center the specimen to avoid losing it outside the FOV
-only use the fine adjustment knob on high and medium power to avoid scratching the lens/cracking the slide

Question 24

How to prepare a wet mount slide

Answer 24

-get a slide, cover, toothpick, specimen, water, and an eye dropper
-put a drop of water in the center of the slide with the dropper
-put the specimen on the water drop
-holding the cover by its edges hold it at a 45 degree angle until it touches the water. place the toothpick under the cover slip using the other hand, slowly lower the toothpick until the cover is completely on the slide
-if any air bubbles, tap gently until gone,

Question 25

In what ways was the compound light microscope limited

Answer 25

The microscope has a max resolution of approx 0.0002 mm, so it could not distinguish objects closer than that (0.2 micrometers). Also some cells were simply too small to be viewed by the light microscope.

Question 26

What is the compound light microscope

Answer 26

Has two lenses mounted at opposite ends of a tube. Max magnification ranges between 1000x to 2000x, uses a mirror or a lamp to reflect light into the device

Question 27

What is the simple microscope

Answer 27

Has one lens, mounted in a metal plate. Max magnification is 400x. First type used by Leeuwenhoek