Methods Of Studing Cells

Question 1

What are microscopes?

Answer 1

Instruments that produce a magnified image of an object.

Question 2

What is the resolution of a light microscope?

Answer 2

0.2 micrometers.

Question 3

What is the resolution of an electron microscope?

Answer 3

0.1 nanometers.

Question 4

What is the magnification of an object?

Answer 4

How many times bigger the image is when compared to the object.

Question 5

What is the equation for magnification?

Answer 5

Magnification = size of image/size of real object.

Question 6

What is the resolution of a microscope?

Answer 6

The minimum distance apart the two objects can be for them to appear separate.

Question 7

What does the resolution depend on?

Answer 7

The wavelength or form or radiation used.

Question 8

What does it mean if a microscope goes beyond its limit of resolution?

Answer 8

Increasing the magnification will not reveal more detail to an object.

Question 9

What is cell fractionation?

Answer 9

The process where cells are broken up and their different organelles are separated.

Question 10

Why is the tissue placed in a cold solution before cell fractionation can begin?

Answer 10

To reduce enzyme activity that might break down organelles.

Question 11

Why is the tissue placed in a buffered solution before cell fractionation can begin?

Answer 11

So the pH does not fluctuate and alter the structure of the organelles or functioning of enzymes.

Question 12

Why is the solution in cell fractionation the same water potential as the tissue?

Answer 12

To prevent osmosis resulting in organelles bursting.

Question 13

What are the two stages of cell fractionation?

Answer 13

Homogenation and ultracentrifugation.

Question 14

What are cells broken up by?

Answer 14

A homogeniser (blender).

Question 15

What does the homogeniser do?

Answer 15

Releases the organelles from the cell.

Question 16

What is the homogenate?

Answer 16

The resultant fluid from the homogeniser.

Question 17

Why is the homogenate filtered?

Answer 17

To remove any complete cells and large debris.

Question 18

What is ultracentrifugation?

Answer 18

The process where the fragments in the filtered homogenate are separated in a machine called a centrifuge.

Question 19

What does a centrifuge do?

Answer 19

Spins tubes of homogenate at a very high speed to crate a centrifugal force.

Question 20

How is the tube of filtrate in the centrifuge spun to start with?

Answer 20

At a low speed.

Question 21

What happens to the organelles as they are spun in the centrifuge?

Answer 21

The heaviest organelles are forced to the bottom of the tube.

Question 22

What is formed at the bottom of the tube in the centrifuge?

Answer 22

A thin sediment or pellet.

Question 23

What is the supernatant?

Answer 23

The fluid at the top of the tube in a centrifuge.

Question 24

Where is the supernatant transferred to?

Answer 24

Another tube.

Question 25

What happens to the supernatant that has been transferred?

Answer 25

Its spun in the centrifuge at a faster speed than before.

Question 26

What happens as the centrifuge increases in speed with each newly transferred supernatant?

Answer 26

The next heaviest organelle is sedimented and separated.