Tissue Fixation

Question 1

1nm=? Angstrom
The thickness of plasma membrane is ?A

Answer 1

10
75

Question 2

2 methods to fix tissue
Which one is EM preferable?

Answer 2

Perfusion & Immersion
Perfusion

Question 3

Steps for fixation(8)

Answer 3

1.Fixation: chemical solution
2.Dehydration
3.Clearing: xylene replaced ethanol
4.Infiltration: 50% xylene & 50% paraffin
5.Embedding: 100% paraffin—>wax
6.Sectioning: microtome
7.Rehydration
8.Staining

Preparation for TEM: plastic and lead citrate

Question 4

Basophilic & Acidophilic structure

Answer 4

B: anions, acidic structure like nucleic acid and ribosome
A: cations, basic structures like cytoplasm

Question 5

H & E stain

Answer 5

Hematoxylin: basic dye
Eosin: acidic dye

Question 6

What are the dark & bright places called in TEM photo

Answer 6

Electron lucent structure: bright
Electron dense structure: dark, ex.membrane and desmosome

Question 7

Resolving power of LM and EM

Answer 7

Light microscope: 1000x
Electron microscope: 160,000x—>1600,000x