Tag: carbohydrate and its test

Questions Related to carbohydrate and its test

A reagent added to a sample shows change of colour from green to yellow. It is due to presence of reducing sugar. The test is

  1. Elisa test for detecting AIDS

  2. Benedict's test for detecting glucosuria

  3. Fehling's test for detecting hyperglycemia

  4. Ninhydrin test for detecting glucosidic linkage


Correct Option: B
Explanation:
Benedict's test can be used to test reducing sugar that is glucose in urine. Glucose in urine is called glucosuria and it turns yellow in colour when benedict's test applied it shows that glucose is present in urine.
So the correct answer is B.

Iodine test used to detect

  1. Protein

  2. Fat

  3. Carbohydrate

  4. Chitin


Correct Option: C

Starch changes colour and turns blue-black in ............ solution.

  1. Salt

  2. Eosin

  3. Iodine

  4. Dilute HCl


Correct Option: C
Explanation:

Iodine present in the aqueous Potassium iodide solution gets entangled in the starch and forms starch Iodide complex. Hence starch turns blue-black or purple-black in colour.

So, the correct answer is option C.

A leaf is boiled in alcohol before using iodine for a starch test in order to

  1. dissolve starch

  2. dissolve chlorophyll

  3. soften the leaf

  4. make it react with iodine


Correct Option: A

What is the $R.Q.$ of glucose?

  1. One

  2. Less than one

  3. More than one

  4. Infinite


Correct Option: A

The post prandial glucose can be measured 

  1. Empty stomach

  2. Any time

  3. 2 hours after lunch / dinner

  4. Early in the morning


Correct Option: C
Explanation:

Blood glucose levels are maintained by hormones, such as insulin and glucagon. A postprandial glucose test is a blood glucose test that determines the amount of glucose in the blood after a meal. Normally, blood glucose levels increase slightly after eating. This increase causes the pancreas to release insulin. A postprandial blood glucose test measures blood glucose exactly 2 hours after eating a meal. By this point, blood sugar has usually gone back down in healthy people, but it may still be elevated in people with diabetes.

For the test of sugars _______ is used.

  1. Fehling's solution

  2. Benedict's solution

  3. Iodine solution

  4. All of the above


Correct Option: D
Explanation:

A little glucose is added to a blue green chemical called as Fehling's solution in a test tube for test of glucose.

Benedict's solution can be used for detecting reducing sugars.
Iodine solution also called as Lugol's reagent is used for detection starch and complex sugars. So, the correct answer is option D. 

Which of the following gives Fehling's test? 

  1. Pectin

  2. Sucrose

  3. Cellulose

  4. Glucose


Correct Option: D
Explanation:

Fehling's test is given by glucose, which is a reducing sugar. It produces a red precipitate with Fehling's solution A and B, when heated.

How many NADH molecules are produced during the complete breakdown of one molecules of glucose?

  1. 5

  2. 10

  3. 30

  4. 6


Correct Option: A

Fehlings solution is used to detect 

  1. Sucrose

  2. Glucose

  3. Fat

  4. Starch


Correct Option: B
Explanation:

Fehlings can be used to screen for glucose in urine, thus detecting diabetes. 

So, the correct answer is option B.