Lab 1

Question 1

identify the light microscope components

Answer 1

1. Eye pieces
2. Stage clip
3. on off switch
4. light intensity regulator
5. Mechanical stage knobs
6. Fine and coarse adjustment knobs
7. illuminator
8. iris diaphragm
9. condenser and condenser adjustment lever
10. stage
11. objectives and resolving nose pieces
12. arm and base

Question 2

function of the arm in a microscope

Answer 2

supports the body tube and lenses. use the arm to carry the microscope

Question 3

function of the base in a microscope

Answer 3

supports the entire microscope. broad and heavy, the base gives the instrument stability.

Question 4

how many x does the eyepieces magnify the image

Answer 4

10x

Question 5

functions of the coarse and fine adjustment knobs

Answer 5

coarse: very sensitive, changes the height, only used in 4x objective.
fine: allows for fine focus when using any objective.

Question 6

function of the condenser in a microscope

Answer 6

collects and concentrates light onto the specimen and projects the image. Can be controlled to optimize resolution and contrast of the image viewed and reduce glare.

Question 7

condenser adjustment lever?

Answer 7

if the lever goes down, condenser up

lever up, condenser down

Question 8

the lower the magnification, the __ the condenser should be positioned in the optical path.

Answer 8

higher

Question 9

mechanical stage knobs function in a microscope?

Answer 9

allows to move the slide in the X or Y direction very smoothly and slowly by turning these knobs.

Question 10

which microscope has 3D view

Answer 10

dissecting (stereoscopic light microscope)

Question 11

light microscopy vs electron microscopy main adv and disadv.

Answer 11

light mic.

adv: can be used to view live specimens
disadv: lowers magnification and resolution powers

electron mic.

adv: highers magnification and resolution powers
disadv: live specimen is killed during the procedure.

Question 12

convert cm to mm to um

1 cm =?=?

Answer 12

1 cm= 10 mm= 1000 um

Question 13

total magnification of microscope

Answer 13

10x (eyepieces) x objective magnification

Question 14

relationship between magnification and working distance

Answer 14

as the magnification increases, working distance decreases. they are inversely proportional.

Question 15

equation of magnification and field diameter to calculate the field diameter at any given magnification

Answer 15

total mag1 x field diam 1 = total mag2 x field diam 2

Question 16

field diameter at (total mag)
40 x?
100 x?
400 x?

Answer 16

4500 um
1800 um
450 um

Question 17

which organelles/parts of plant and animal cells are visible under a light microscope?

Answer 17

animal: nucleus, cytoplasm, plasma membrane
plant: nucleus, cytoplasm, cell wall, central vacuole

Question 18

the cell wall of plants contains mostly

Answer 18

cellulose

Question 19

why did we pour saline solution on the cheek cells and not water

Answer 19

Since animal cells do not have a cell wall, when too much of this water enters to make the concentration of water on both sides even, the animal cell may eventually burst, and die out

Question 20

how to safely put away a microscope

Answer 20

1. put on 4x objective
2. turn light knob all the way down and off switch
3. sample stage to lowest position
4. remove slide
5. place microscope in the cabinet oculars facing inside