lecture 15 cell/tissue staining Flashcards Preview

IS MLSC 1218 > lecture 15 cell/tissue staining > Flashcards

Flashcards in lecture 15 cell/tissue staining Deck (19):
1

what is chromophore

arrangement of atoms that absorb light and produce colour. double bonds or NO2 groups

2

what is auxochrome

functional group that attaches to tissue by chemical bonding/association

3

diff btw oversight stain vs selective stain

oversight for cell morphology e.g. H&E, Wright Geisma. selective stain enhance components e.g. pentachrome stain

4

what makes a good chemical staining method

-good color differentiation
-gives insoluble and stable color
-reproducible
-selective or specific when required
-semi quantitative

5

relationship btw pka, pH and ionization of tissue acidic group

acidic group: pH greater than pka ionization is favoured, more than 50% groups -ive

6

relationship btw staining pH and net tissue protein charge

can influence what tissue groups are ionized

7

effect of changing pH for Alcian Blue

pH 1-sulfated mucin stained
ph 2 sulfated and carboxylated mucin
pH 5 sulfate/carboxylated mucin and proteins stained

8

why changing staining pH affects intensity of cationic and anionic dye

eg more -ive charges mean more group for cationic dye to attach to. cationic stain intensity increases

9

why 100% of a cationic dye’s auxochromes remain ionized at the pH used for staining tissue anionic groups

n

10

why 100% of an anionic dye’s auxochromes remain ionized at the pH used for staining tissue cationic groups

auxochromes of anionic dyes are carboxyl or sulfonyl groups pka less than 2. pH for staining cationic tissue groups ph greater than 2

11

ionized acid groups are ___ charged

negatively

12

cationic dyes that have a positive charge when ionized (basic)

Alcian Blue and Azure B

13

anionic dye that has a negative charge when ionized (acidic)

Eosin Y. stains orange pink

14

as pH decreases ionization of ___ is favoured

basic amine groups. ionized amine are +ive charge (cationic tissue group) (anionic dye is favour red eosin Y)

15

when is ionization favoured for acidic fnal groups

when pka is lower acid will lose H atom and more than 50% will be negative

16

when is ionization favoured for basic fnal groups

when pka is higher base will accept H and more than 50% positive

17

auxochromes of anionic dyes are primarily

carboxyl or sulfonyl groups

18

wright-geimsa stain consist of 2 stains

methylene blue (cationic) and eosin (anionic) pH 6.4

19

increase in pH means

increase in net -ive charge. cationic dyes intensifies such azure B. blue colour