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प्रश्न
Three cyclic structures of monosaccharides are given below which of these are anomers.
| (I) |  |
| (II) |  |
| (III) |  |
विकल्प
I and II
II and III
I and III
III is anomer of I and II
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उत्तर
I and II
Explanation:
This behaviour could not be explained by the open-chain structure (I) for glucose. It was proposed that one of the –OH groups may add to the –CHO group and form a cyclic hemiacetal structure. It was found that glucose forms a six-membered ring in which –OH at C – 5 is involved in ring formation. This explains the absence of –CHO group and also existence of glucose in two forms as shown below.
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संबंधित प्रश्न
Write two main functions of carbohydrates in plants.
Classify the following into monosaccharides and disaccharides.
Ribose, 2-deoxyribose, maltose, galactose, fructose and lactose
The number of primary and secondary hydroxyl groups in ribose are -
(a) 1, 3
(b) 2, 3
(c) 3, 1
(d) 3, 2
Glycosidic linkage is found between ____________.
Which of the following gives a positive Fehling solution test?
A carbohydrate that cannot be hydrolysed into simpler units is called ____________.
Reducing sugars reduce ____________.
Which of the following reagent cannot distinguish between glucose and fructose?
Structure of a disaccharide formed by glucose and fructose is given below. Identify anomeric carbon atoms in monosaccharide units.
Monosaccharides contain carbonyl group hence are classified, as aldose or ketose. The number of carbon atoms present in the monosaccharide molecule are also considered for classification. In which class of monosaccharide will you place fructose?
What are glycosidic linkages? In which type of biomolecules are they present?
Which monosaccharide units are present in starch, cellulose and glucose and which linkages link these units?
Assertion: Deoxyribose, \[\ce{C5H10O4}\] is not a carbohydrate.
Reason: Carbohydrates are hydrates of carbon so compounds which follow \[\ce{C_x(H2O)_y}\] formula are carbohydrates.
Account for the following:
Glucose is a reducing sugar
Reagent X is:
The following questions are case-based questions. Read the passage carefully and answer the questions that follow:
| Carbohydrates are optically active polyhydroxy aldehydes and ketones. They are also called saccharides. All those carbohydrates which reduce Fehling's solution and Tollen's reagent are referred to as reducing sugars. Glucose, the most important source of energy for mammals, is obtained by the hydrolysis of starch. Vitamins are accessory food factors required in the diet. Proteins are the polymers of α-amino acids and perform various structural and dynamic functions in the organisms. Deficiency of vitamins leads to many diseases. |
Answer the following:
(a) The penta-acetate of glucose does not react with Hydroxylamine. What does it indicate? (1)
(b) Why cannot vitamin C be stored in our body? (1)
(c) Define the following as related to proteins: (2)
- Peptide linkage
- Denaturation
OR
(c) Define the following as related to carbohydrates: (2)
- Anomers
- Glycosidic linkage
