METHOD OF STUDYING CELLS

Question 1

Magnification

Answer 1

magnification is how much bigger the image is than the specimen.

Question 2

resolution

Answer 2

resolution is how detailed the image is

Question 3

types of microscope

Answer 3

optical microscope and electron microscope

Question 4

optical microscope

Answer 4

• uses light to form an image.
• have a maximum resolution of about 0.2 micrometers, cant view organelles smaller than that.
• have a maximum magnification about x1500.

Question 5

electron microscope

Answer 5

• uses electron to form an image.
• have amaximum resolution of about 0.0002 micrometers
• maximum magnification of 150000.

Question 6

types of electron microscope

Answer 6

scanning electron microscope and transmission electron microscope.

Question 7

TEM

Answer 7

• uses electromagnets to focus on a beam of electrons.
• denser part of specimen absorb more electrons, making them look darker .
• have a high resolution image to see the internal structure of organelles.
• can only be used on thin specimen.

Question 8

SEM

Answer 8

scans a beam of electrons across the specimen.
- shows up 3d images
- can be used on thick specimens but gives a lower resolution images than TEM.

Question 9

cell fractionation

Answer 9

homogenisation, filtration and ultracentrifugation

Question 10

homogenisation

Answer 10

• vibrating the cells or grinding them in a blender, breaking up the plasma membrane and releasing the organelles into the solution
• solution must be kept ice cold, isotonic to prevent damage to organelles by osmosis and a buffer solution needs to be added to maintain the ph.

Question 11

flitration

Answer 11

• now the homogeonmised cell is filtered through a gauze to separate heavy large cell debris or tissue debris.

Question 12

ultracentrifugation

Answer 12

• cell fragments are then poured into a tube, and is put into a centrifuge.
• heaviest organelles set up at bottom , tje pellet
• lighter organelles at the tube called the supernatant.