Exp. 1 Extra

Question 1

Protein is linked together with peptide bonds with a positive charged_______-containing group at one end and a negatively charged ________-group.

Answer 1

nitrogen

carboxyl

Question 2

Biuret test is conveniently used to detect the presence of_______ or_______ in biological fluids.
It produces a_______ color.

Answer 2

proteins or peptide bonds

purple

Question 3

Ninhydrin Test is to detect the presence of free alpha-____acids,_____,__________ and_______

Answer 3

amino

proline

hydroxyproline

asparagine

Question 4

Ninhydrin test

It produces:
deep violet/blue color = _______
yellow-orange = for _______ and _______
brown color = for________

Answer 4

free amino acids

proline and hydroxyproline

asparagine

Question 5

Hopkins- Cole

Test detect the presence of ______.
It produces a_____ color.

Answer 5

tryptophan

violet

Question 6

Sakaguchi test

To detect the presence of______ in either free form or in proteins.
It produces a______ color.
No red-color means presence of ______ or ________.

Answer 6

arginine

red

glycine or albumin

Question 7

Xanthoproteic
To detect the presence of _____, ______, and _______.

Answer 7

tryptophan, tyrosine and phenylalanine

Question 8

Xanthoproteic It produces:

yellow color to _________ and;
orange with the presence of an____.

Answer 8

nitro derivatives

alkali

Question 9

Biuret is a compound formed by heating____ at 1800 which results in the condensation of 2 molecules of urea

Answer 9

urea

Question 10

It is considered as a general test for compounds (proteins and peptides) having two or more peptide (CO-NH) bonds

Answer 10

Biuret

Question 11

This test is a general test and is thus given by all amino acids

Answer 11

Ninhydrin

Question 12

is a powerful oxidizing agent and its presence, amino acid undergoes oxidative deamination liberating ammonia, CO2, a corresponding aldehyde, and a reduced form of ninhydrin (hydrindantin)

Answer 12

Ninhydrin

Question 13

The NH3 formed from an amino group reacts with another molecule of ninhydrin and is a reduced product (hydrindantin) to give a deep blue or purple substance diketohydrin (_________purple).

Answer 13

Rheumanns

Question 14

In ninhydrin test:________, which has a free amide group, reacts to give a brown-colored product.

Answer 14

Asparagine

Question 15

ninhydrin does not react strongly with

Answer 15

tyrosine, tryptophan, and phenylalanine.

Question 16

The indole group of_______ reacts with glyoxylic acid in the presence of conc. H2SO4 to give a purple colour.

Answer 16

tryptophan

Question 17

Glyoxylic acid is prepared by reducing_______ with ________ or _________.

Answer 17

oxalic acid

magnesium powder or sodium amalgam

Question 18

Sakaguchi test is based on the principle of reaction between 1-naphthol and the______ groups in arginine, in the presence of an oxidizing agent.

Answer 18

guanidinium

Question 19

Xanthoproteic test is based on the fact that aromatic groups in the amino acids are nitrated by heating with____________ to yield intensely yellow-colored nitro derivative.

Answer 19

concentrated HNO3

Question 20

Xanthoproteic: On the addition of______, however, the residue turns orange due to the formation of a salt of the tautomeric form of the nitro compound.

Answer 20

alkali

Question 21

Benzene ring-containing amino acids like phenylalanine don’t give a positive test to this test because the phenyl group in phenylalanine is very stable, which doesn’t react with nitric acid in the conditions of this test.

Answer 21

Xanthoproteic