Topic 2 - Studying Cells Flashcards
What is magnification?
How much bigger the image is compared to the specimen
What is resolution?
How well a microscope distinguishes between 2 points that are close together.
How do optical microscopes form an image?
Using light
Max resolution of an optical microscopes
0.2 micrometers
What organelles could you view under an optical microscope?
Ribosomes
Endoplasmic Reticulum
Lysosomes
Nucleus
Name 2 types of electron microscopes
Transmission electron microscope
Scanning electron microscope
Explain how a TEM works
Use electromagnets to focus beam of electron which are then transmitted through a specimen, denser parts absorb more elections (darker).
Explain how a TEM works
Use electromagnets to focus beam of electron which are then transmitted through a specimen, denser parts absorb more elections (darker).
Advantages and disadvantages of a TEM
+ = high resolution
- = view in vacuum (dead specimen)
Explain how an SEM works
Scan a beam of elections across the specimen, knocks off electrons from specimen, can be 3D
Advantage and disadvantage of SEM
+ = living specimen
- = expensive and very large
What is cell fractionation?
Separating the organelles of a cell by their mass.
What are the 3 main steps of cell fractionation?
Homogenisation
Filtration
Ultracentrifugation
Explain homogenisation
Cell is blended into a solution where the organelles are released into solution (cold, isotonic, pH).
