Chapter Z

Question 1

What is a microscope?

Answer 1

A microscope is an instrument that is used to view a specimen or the details in the specimen that cannot be seen with the naked eye.

Question 2

The light microscope (LM)

Answer 2

Visible light is passed through a specimen and then through glass lenses.

Question 3

Electron microscope ( em )

Answer 3

Focuses a beam of electrons through the specimen or onto it’s surface.

Question 4

Types of light microscope

Answer 4

1) compound microscope

2) stereomicroscope or dissecting microscope.

Question 5

Define the compound microscope:

Answer 5

⭐️🍰 has a minimum of two magnifying lenses (the ocular & the objective lenses)9 which gives a compound magnification of 40X-1000X.

⭐️🍰 illumination is from below and the light is transmitted through the specimen and the magnified by objective & ocular lenses.

⭐️🍰 used to study details of very small and thin speicmens.or thin sections of materials prepared from larger specimens.

Question 6

Define the dissecting microscope. (Stereomicroscope)

Answer 6

1) has a relatively low magnification ( 7 X - 30 X )
2) the advantages of dissecting microscopes :-
** it shows the speimen is the three dimension.
** it is used for viewing large or opaque specimens.
** it provides a large working distance that allows for manipulation or dissection of the specimen.

Question 7

Magnification,

Answer 7

A measurement of how big a object looks to your eyes compared to it’s real size

Question 8

How can you write a magnification (describe) for a microscope??

Answer 8

Magnification is usually written by a number followed by the letter (x) which means “times real size”

Question 9

Does all microscopes have the same magnification?

Answer 9

Different microscopes have different magnifications based on the objective lenses included in them.

Question 10

Objective lenses magnification is usually :

Answer 10

1) low/ scanning power (4x)
2) medium power ( 10 X )
3) high power ( 40X)
4) oil immersion (100X)

Question 11

Ocular lenses magnification is usually;

Answer 11

10 or 15 depending on the microscope.

Question 12

How to calculate total magnification of a microscope,

Answer 12

Total magnification = magnification of ocular lens * magnification objective lenses

Question 13

What will happen to the field of view when the magnification increase?

Answer 13

When the magnification increases, the field of view or the area that you are able to see at one time decrease.

Question 14

What is the filed of view??

Answer 14

The area that you are able to see at one time.

Question 15

Define Resolution

Answer 15

• The measurement of the clarity of the image ‘
  & the minimum distance of two distinguishable points.

Question 16

What does resolution determine?

Answer 16

• It determine how well specimen detail is preserved during the magnifying process.

Question 17

Define contrast

Answer 17

The difference in brightness between the light or dark areas of an image.

Question 18

Microscopy parameters :

Answer 18

• • magnification : the measure of how big an object looks to your eyes compared to it’s real size.

** resolution : the measurement of the clarity of the image, Or the minimum distance between two distinguishable points.

** contrast : the difference in brightness between light & dark areas of an image..

Question 19

The light passes from the light source through —

Answer 19

Through the condenser lease, to focus light on the specimen.

The condenser lens in in the diaphragm, where the level of light can be adjusted.

Question 20

Why objective lenses attacked to a nosepiece.

Answer 20

*) objective lenses are attached to the nose piece.
*) nosepiece allows objective lenses to rotate so you can select a certain one to use.

Question 21

Mention the knobs in the microscope:

Answer 21

1) coarse focus

2) fine focus.

3) stage knobs.

Question 22

What do the coarse. & fine focuses do?

Answer 22

• Both of these knobs raise or lower the stage which helps in the focusing

The coarse focus knob will move it more dramatically, whereas the fine focus knob will move it in smaller increments.

Question 23

Eye piece/ ocular sense is attached on?

Answer 23

Observation tube.

Question 24

The stage knobs (or the co-axial stage controls) do =

Answer 24

Move the stage from side to side (horizanta) movement)

Helps explore what’s on the slide itself.

IT doesn’t adjust the focus on the specimen.

Not all microscopes have those stage knobs sometimes you have to move the slide manually 

Question 25

How to hold the microscope??

Answer 25

• Carry the microscope assigned to you with both hands.

& make sure to have on hand underneath supporting the base, and the other hand holding the microscope are.

Question 26

When getting the microscope, we should!’

Answer 26

• Remove the dust cover.
• clean the lenses with lens paper.
• start your microscope study by using low power objective lens. First-,

Question 27

When using the high power lens & oil immersion at the microscope, the object should be:

Answer 27

The object should be covered with cover slip.

Question 28

What should you avoid when using microscopes?

Answer 28

Avoid getting water or other materials on the microscope.

🔬 avoid touching the objective & ocular lenses with your finger.

Question 29

When finish using the microscope:

Answer 29

1) remove the slide from the stage.
2) make sure that the low power lens is in the upright position.
3) cover the microscope
U) then store it in the cabinet.

Question 30

What would you do if any part of your microscope is damaged?

Answer 30

1) report instructor
2) don’t try to repair any damage by yourself.

Question 31

Wet mounts are used to:

Answer 31

• Study fresh materials.
• they are temporary slides used to study the color, movement, behavior of the specimen that cannot be observed on dead and stained materials.

Question 32

Examples about dyes in microscopes that are used to increase contrast :

Answer 32

🩵 lugols iodine
🩵 methylene blue
💜 crystal violet

Question 33

How to avoid air bubbles in the slide in the microscopes?

Answer 33

Set the cover slip on 45° with the horizontal of the slide above the droplet.💧
Lower the cover of slip slowly to avoid bubbles.🫧

Use a piece of tissue to drain excess water from the sides 

Question 34

How to prepare a wet mount slide

Answer 34

Using a pipe it or disposable pipe, it drop a drop or two of water sample onto the slide put the cover slip by lowering it slowly on the Spiesman to avoid bubbles, then take a piece of tissue during the excess water from the sides.

Question 35

Explain the use of stage clips?

Answer 35

Eclipse on the stage are used to secure the slide .

Question 36

Does the image on the microscope is the same image as the real ?

Answer 36

The image appears upside down and inverted.
The objective lens slips and magnifies the image resulting in the upside down appearance .

(N the magnification is due to the objective and ocular lenses, and the inversion is due to the objective lenses only)

Question 37

Why are using clean glass slides and 10 species in the compound light microscope

Answer 37

So the light can transmit through the glass and the specimen , and then magnified by objective and occur

Question 38

Why are using coverslips to cover the specimen ?

Answer 38

• they protect the specimen.
• flatten them for better focus.
  *. Keep tiny things safe from dirt and mess and shield from debris.

Question 39

Why do we use small E in your first experiment not the capital

Answer 39

Because the E has more details and complicity with its curves and angles

It’s easier to notice the upside down appearance, and to notice that it’s inverted

Question 40

Why are dyes used in the microscope?

Answer 40

To increase the contrast