Exp. 5 Flashcards
(if sample is plant) – done by mechanical disruption through crushing or blending
Breaking of cell wall
Breaking of cell membrane to expose organelles – done by adding the____________ which is an amphipathic substance
dishwashing liquid
The long hydrocarbon tail of ________ breaks the lipid bilayer of cell membrane while the _______ polar head is attracted to the water
soap
binds to the negatively charges phosphate end of the DNA chain to protect the chain as well as increases the separation of DNA from the hydrophobic layer
Salt
removes cellular debris from the sample
Filtration
Precipitation with cold alcohol
▪ DNA becomes_______ in water in the presence of salt and alcohol (more polar)
insoluble
DNA is more soluble to______ than_____ (because it is more polar),
alcohol
water
Sugar + Nitrogen Base
Nucleoside
Bonds between sugar ang base
Glycosidic bonds
Bonds between sugar + phosphate
Phosphodiester bonds
- removes the lipids and push DNA to the salt solution
dishwashing liquid
- increases separation of negatively of DNA from hydrophobic layer; aggregates DNA
sodium chloride
– promotes aggregation of DNA and wash the DNA from the salt
Add cold ethanol
Nucleotide is composed of
base
sugar
phosphate group
joins the base and the sugar
Glycosidic bond
joins the phosphate and sugar group
phosphodiester bond
The nucleotide chain is joined together by
phosphodiester bond
break down of glycosidic bonds only if pH ______
> 3
Depurination
Products are purine base and deoxyribose with phosphate group
Depurination
break down of glycosidic bond with phosphodiester bond if pH____ plus____
< 2 + heat
Total breakdown
Extremely low pH hydrolyses DNA________
completely
Products are phosphate group, the purine or pyrimidine base, and deoxyribose
Total breakdown
T or F | it is easy to attack the glycosidic bond than the phosphodiester bond
True!
Test for the deoxyribose in DNA
Dische Diphenylamine Test
Dische Diphenylamine Test reagents
diphenylamine, Sulfuric acid (2)
Dische Diphenylamine Test positive results
light blue to blue solution depending on the amount of DNA
Dische Diphenylamine Test
HYDROLYZED
UNHYDROLYZED
BRIGHT BLUE (+)
BROWNISH BLUE (+)
Test for reducing sugar
FEHLING’S Test
Reagents:
Fehling’s A:
Fehling’s B:
Copper sulfate solution
aqueous potassium sodium tartrate sodium hydroxide
Positive result: formation of brick red precipitate
FEHLING’S Test
is more sensitive to RIBOSE
Test for pentoses
Bial’s Test
Bial’s test reagents
Orcinol
hydrochloric acid
FeCl3
Bial’s test Positive result
Blue or green solution
Test for the presence of Adenine and Guanine
Test for Purine Bases
will tell if successfully na remove ang purine (AG) during hydrolysis
Test for Purine Bases
Test for Purine Bases reagents
Silver Nitrate
Ammonium Hydroxide
In test for purine bases, _______ in ammoniacal solution precipitates purine bases reacting to the nitrogen of purine base
Silver ion
Positive result: gelatinous white precipitate
Test for Purine Bases
Phosphate Test reagents
Ammonium hydroxide
nitric acid
ammonium molybdate
Positive result: Yellow precipitate
Phosphate Test
(NH4)3PMo12O40 6H2O
Ammonium phosphomolybdate ____
