B1: MICROSCOPY + MAGNIFICATION

Question 1

Magnification equation?

Answer 1

M=I/A
Magnification = image size/actual size

Question 2

How do you convert mm to micrometers?

Answer 2

x 1000

Question 3

Define magnification

Answer 3

How many times bigger the image is than the real object

Question 4

Define resolution

Answer 4

Ability to distinguish between 2 points: greater detail and sharper image

Question 5

What’s the difference between a light microscope and an electron microscope?

Answer 5

-light microscope uses light and lens whereas electron microscope uses beam of electrons
-electron microscope has higher magnification (light microscope’s highest magnification is x1,500 whereas electron microscope’s highest magnification is x1,000,000)
-electron microscope has higher resolution

Question 6

How to prepare a slide (to view onion cells)

Answer 6

-add a drop of water to a clean slide
-cut an onion into layers and use tweezers to peel off some epidermal tissue from one of the layers
-add layer of onion to the slide
-add a drop of iodine
-place a cover slip on top (stand cover slip upright on the side next to the water droplet then carefully tilt and lower it so it covers the specimen)

Question 7

How to use a microscope to look at a slide

Answer 7

-clip slide onto stage
-select lowest powered objective lens
-use coarse adjustment knob to move stage up just below objective lens
-look down eyepiece and use coarse adjustment to knob to move stage downwards until the image is roughly in focus
-adjust focus with fine focus knob until image is clear
-if u need to see slide with higher magnification swap to a higher powered objective lens

Question 8

How to draw observations?

Answer 8

-at least half of space available
-clear unbroken lines
-no shading or colouring
-sub-cellular structures drawn in proportion
-name of specimen + magnification
-label important features