Analysis Of Cell Componenets

Question 1

What is magnification?

Answer 1

How much bigger the image is than the specimen

Question 2

What is the formula for magnification?

Answer 2

Size of image ÷ size of real object

Question 3

How do you convert nanometres into micrometers?

Answer 3

÷1000

Question 4

How do you convert micrometres into millimetres?

Answer 4

÷1000

Question 5

What is the resolution?

Answer 5

How well a microscope distinguishes between 2 points that are close together

Question 6

What are the 2 types of microscope?

Answer 6

Optical

Electron

Question 7

What are optical microscopes?

Answer 7

Use light to form an image

Question 8

What is the maximum resolution of an optical microscope?

Answer 8

0.2 micrometers

Question 9

What is the maximum useful magnification of an optical microscope?

Answer 9

x1500

Question 10

What can you see with an optical microscope?

Answer 10

Mitochondria

Nucleus

Question 11

What are electron microscopes?

Answer 11

Use electrons to form an image

Question 12

What is the maximum resolution of an optical microscope?

Answer 12

0.0002 micrometers

Question 13

What is the maximum useful magnification of an electron microscope?

Answer 13

x1 500 000

Question 14

What are the 2 types of electron microscope?

Answer 14

Transmission

Scanning

Question 15

What are transmission electron microscopes?

Answer 15

Use electromagnets to focus a beam of electrons which is then transmitted through the specimen

Question 16

Why do denser parts of the specimen look darker on the image?

Answer 16

Absorb more electrons

Question 17

What are the advantages of TEMs?

Answer 17

Give high resolution images so can see internal structures of organelles

Question 18

What is are the disadvantages of TEMs?

Answer 18

Have to view specimen in a vacuum so cannot look at living specimens

Only used on thin specimens

Question 19

What are scanning electron microscopes?

Answer 19

Scan a beam of electrons across a specimen which knocks of electrons from specimen which are gathered in a cathode ray tube to form an image

Question 20

What are the images like in SEMs?

Answer 20

Show surface of specimen

Can be 3D

Question 21

What is an advantage of SEMs?

Answer 21

Can be used on thick specimens

Question 22

What is a disadvantage of SEMs?

Answer 22

Give lower resolution images than TEMs

Question 23

What is cell fractionation?

Answer 23

Separating organelles from the rest of the cell

Question 24

What are the 3 steps of cell fractionation?

Answer 24

Homogenisation

Filtration

Ultracentrifugation

Question 25

What does homogenisation do?

Answer 25

Breaks up plasma membrane and releases organelles into solution

Question 26

2 ways of homogenisation?

Answer 26

Vibrating cells Grinding cells in a blender

Question 27

What are the 3 conditions for homogenisation?

Answer 27

Ice cold Isotonic solution Buffer solution

Question 28

Why must the solution be kept ice cold in homogenisation?

Answer 28

To reduce enzyme activity

Question 29

Why must the solution be isotonic?

Answer 29

Prevents damage to organelles though osmosis

Question 30

What does an isotonic solution mean?

Answer 30

Same concentration of chemicals as the cells being broken down

Question 31

What does the buffer solution do?

Answer 31

Maintains the pH

Question 32

What happens after the cell solution is homogenised?

Answer 32

Filtered through gauze to separate any large cell debris or tissue debris

Question 33

What is left after filtration?

Answer 33

A solution containing a mixture of organelles

Question 34

How can you separate a particular organelle from all the others?

Answer 34

Ultracentrifugation

Question 35

What is the process of ultracentrifugation?

Answer 35

Cell fragments poured into tube Tube put in centrifuge and spun at low speed Supernatant reined off into another tube and spun at a higher speed in centrifuge Process repeated at higher speeds until all organelles are separated out

Question 36

Why is the solution spun in a centrifuge?

Answer 36

To separate heavies organelles from lightest

Question 37

What happens to the heaviest organelles in ultracentrifugation?

Answer 37

Form a thick sediment called a pellet at bottom of tube