Does anyone have Arya publication's BIOLOGY LAB MANUAL for class 11?? I would like to have the whole experiment of testing sugar in urine. Random answers will be reported..
Answers
Answer:
Test For Presence Of Sugar In Urine
Aim
To perform a test detecting the presence of sugar in the given sample of urine.
Theory
Urine is an excretory liquid waste, produced by a pair of a kidney, which needs to be eliminated from our body. Through the process of urination, urine is excreted from the urethra. In humans, urine is a pale yellowish liquid containing water and several other chemical components such as uric acid, urea, traces of enzymes, hormones, and carbohydrates.
Properties Of Urine
It has a characteristic pale yellow colour.
The yellow colour is imparted by the yellow pigment known as urochrome.
The urine pH ranges from 4.6 to 8.
More than 95% of urine constitutes water.
Organic substances of nitrogenous origins found in urine are creatine, uric acid, urea.
Other organic matter in urine are lactic acid, oxalic acid.
Inorganic constituents are potassium chloride, sodium chloride, phosphates, and sulphates.
Urine abnormally can contain other constituents such as ketone bodies, sugar(glucose), protein, bile and blood.
Glucose is usually not found in urine. It appears when in blood, the glucose levels exceed the renal threshold of glucose i.e., 160 to 180 mg/dl.
When glucose is present in urine it is termed as glucosuria. It indicates diabetes mellitus.
Also Read: Diabetes mellitus.
Sugar presence in a sample of urine can be detected by performing the following two tests:
Benedict’s test
Fehling’s test
What is Benedict’s Test?
A Benedict’s solution serves as a reagent in this test. The reagent is a blend of copper, sodium citrate and sodium carbonate and copper II sulphate pentahydrate (CuSO4.5H2O)
What is Fehling’s test?
In this test, the two different types of Fehling’s solution are used:
Fehling’s solution – A: Aqueous solution of copper II sulphate – Blue colour solution.
Fehling’s solution – B: Aqueous solution of sodium potassium tartrate – Clear and Colourless solution.
When the urine sample is boiled with the two different reagents, the CuSO4 found in Benedict’s and Fehling’s solution is reduced by the reducing agent, glucose for the formation of a coloured cuprous oxide precipitate. Depending on the glucose concentration, a yellow, green and brick-red formation of precipitates of oxides take place.
The table below depicts the colour sequence on the basis of glucose level concentration.
Sugar level (Percentage)
Precipitate colour
Absence of sugar
Blue
0.5%-1%
Green1%-2%
Yellow
2% or higher
Brick red
1. Benedict’s Test