Correct Answer - A
Ans. is 'a' i.e., Homogentisic acid
Alkaptonuria
It is due to deficiency of homogentisate oxidase. As a
result homogentisic acid (homogentisate) is excreted
execessively in urine. There are three important characteristic
features in alkaptonuria?
1. Urine becomes dark after being exposed to airQ. It is due
spontaneous oxidation of homogentisate into benzoquinone
acetate, which polymerse to form black-brown pigment alkapton which imparts a characteristic black-brown colour to urine.
2. Alkapton deposition occurs in sclera, ear, nose, cheeks and
intervertebral disc space. A condition called ochronosis. There
may be calcification of intervertebral discs Q.
3. Onchronosis arthritis affecting shoulder, hips, knee.
4. Benedict's test is strongly positive in urine and so is the ferric chloride (Pea) testQ. Benedict's reagent gives a greenish brown precipitate with brownish black supernatent. Fehling's reagent (FeC13 ) gives blue green colour
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