Studying Cells

Question 1

An Electron microscope has a very ______ resolution

Answer 1

High

Question 2

Why use an electron microscope as opposed to a light microscope?

Answer 2

You can see inside organelles

Question 3

Why does the specimen have to be one cell thick for a light microscope?

Answer 3

Wavelength of light does not fit through stacks of cells

Question 4

Why use a stain for a light microscope?

Answer 4

To be able to easily view the structures

Question 5

What are the three steps of Cell Centrifugation?

Answer 5

Homogenisation

Filtration

Ultracentrifugation

Question 6

Describe the homogenisation process

Answer 6

Plasma membrane is broken up to release organelles into solution

Question 7

What are the required conditions for homogenisation, and why?

Answer 7

Ice cold - reduce hydrolytic enzyme activity which would cause damage to organelles

Isotonic - Same water potential as organelles so they won’t burst or shrivel

Buffered - prevents denaturing of enzymes

Question 8

Describe the process of filtration

Answer 8

Organelles are filtered through a gauze

This separates organelles from cell debris

Question 9

Name the organelles removed after ultracentrifugation from heaviest to lightest

Answer 9

Nucleus

Chloroplasts

Mitochondria

Lysosomes

Endoplasmic Reticulum

Ribosomes