Tag: biological molecules

Questions Related to biological molecules

The relationship between glucose and sucrose is

biology food and it's constituents energy giving food carbohydrate and its test biological molecules

  1. Glucose is sucrose, with an extra -OH group at the $3'$ position.

  2. Sucrose is compared of two glucose molecules joined by a glycoside bond.

  3. A glucose molecule, joined to a fructose molecule makes a molecule of sucrose.

  4. Glucose is compared of two sucrose molecules, joined by a glycoside bond.

  5. Glucose is compared of a fructose and a sucrose molecule, joined by a glycoside bond.

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Correct Option: C
Explanation:

Glucose and fructose are simple sugars known as monosaccharides. Sucrose is a disaccharide. Sucrose is made up of 2 simple sugars - glucose + fructose. 

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

biology biological molecules energy giving food carbohydrate and its test food and it's constituents

  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

Show answer
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

biology biological molecules energy giving food carbohydrate and its test food and it's constituents

  1. Protein

  2. Fat

  3. Carbohydrate

  4. Chitin

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Correct Option: C

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

biology biological molecules energy giving food carbohydrate and its test food and it's constituents

  1. Salt

  2. Eosin

  3. Iodine

  4. Dilute HCl

Show answer
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

biology biological molecules energy giving food carbohydrate and its test food and it's constituents

  1. dissolve starch

  2. dissolve chlorophyll

  3. soften the leaf

  4. make it react with iodine

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Correct Option: A

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

biology biological molecules energy giving food carbohydrate and its test food and it's constituents

  1. One

  2. Less than one

  3. More than one

  4. Infinite

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Correct Option: A

The post prandial glucose can be measured 

biology biological molecules energy giving food carbohydrate and its test food and it's constituents

  1. Empty stomach

  2. Any time

  3. 2 hours after lunch / dinner

  4. Early in the morning

Show answer
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.

biology biological molecules energy giving food carbohydrate and its test food and it's constituents

  1. Fehling's solution

  2. Benedict's solution

  3. Iodine solution

  4. All of the above

Show answer
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? 

biology biological molecules energy giving food carbohydrate and its test food and it's constituents

  1. Pectin

  2. Sucrose

  3. Cellulose

  4. Glucose

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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?

biology biological molecules energy giving food carbohydrate and its test food and it's constituents

  1. 5

  2. 10

  3. 30

  4. 6

Show answer
Correct Option: A