methods of studying cells

Question 1

How far apart do 2 objects need to be for a light microscope to distinguish between them ?

Answer 1

0.2 um

Question 2

how far do 2 objects need to be for an electron microscope to distinguish between them ?

Answer 2

0.1 nm

Question 3

what can electron microscopes distinguish between objects better than light microscopes ?

Answer 3

a beam of electrons has a shorter wavelength than light .

Question 4

what is magnification ?

Answer 4

how much times bigger the image is compared to the actual object

Question 5

how do you find the magnification ?

Answer 5

size of image /size of real object

Question 6

what is resolution ?

Answer 6

the shortest distance between 2 points on an object that can still be distinguished as 2 different entities

Question 7

list the unites of difference ?

Answer 7

nm,um,mm,m,km

Question 8

how do you switch between the units of difference going from smallest to largest ?

Answer 8

divide by 1000 for each

Question 9

how do you switch between the units of difference going from largest to smallest ?

Answer 9

times by 1000

Question 10

what are the two types of electron microscopes ?

Answer 10

Transmission electron microscopes and scanning electron microscopes

Question 11

how does a TEM work ?

Answer 11

TEMs use electromagnets to focus a beam of electrons, which is then transmitted through the specimen. Denser parts of the specimen absorb more electrons, which makes them look darker on the image you end up with.

Question 12

What is one disadvantage of using a TEM ?

Answer 12

Can only be used on
thin specimens.Can only be used on non-living specimens

Question 13

what is one advantage of TEM?

Answer 13

Give high resolution images,
so shows small objects.

Question 14

How does a SEM work ?

Answer 14

SEMs scan a beam of electrons across the specimen. This knocks off electrons from the specimen, which are gathered in a cathode ray tube to form an
image.

Question 15

what are the disadvantages of using SEM?

Answer 15

Give lower resolution
images than TEMs.
Can only be used on non-living specimens.

Question 16

what are the advantages of using SEM?

Answer 16

Can be used on thick
specimens. Can be 3-D.

Question 17

what is the first step to preparing a microscope slide ?

Answer 17

pipette a small drop of water onto the centre of the slide

Question 18

what is the second step of preparing a microscope slide ?

Answer 18

Use tweezers to place a thin section of the specimen onto of the water drop

Question 19

what is the third step of preparing a microscope slide ?

Answer 19

Add a drop of a stain.

Question 20

give 2 examples of stain and what they’re used for

Answer 20

Eosin is used to make the cytoplasm show up. Iodine in potassium iodide solution is
used to stain starch grains in plant cells.

Question 21

what is the fourth step of preparing a microscope slide ?

Answer 21

carefully lower the cover slip down onto the water drop