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प्रश्न
Explain D and L configuration in sugars.
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उत्तर
D and L configuration in sugars:
- Conventionally (+)-glyceraldehyde is represented by the Fischer projection formula having –OH group attached to C-2 on the right side and this configuration is denoted by symbol ‘D’.
- Similarly, the configuration of (–) glyceraldehyde is denoted by the symbol ‘L’.
- All the compounds which can be correlated by a series of chemical reactions to (+)-glyceraldehyde are said to have D-configuration.
- And compounds which are chemically correlated to (–)-glyceraldehyde are said to have L-configuration. This is the system of the relative configuration of chiral compounds.
- A monosaccharide is assigned D/L configuration on the basis of the configuration of the lowest chiral carbon in its Fischer projection formula.
- Relative configuration of (+)-glucose with respect to (+)-glyceraldehyde can be drawn as follows:
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संबंधित प्रश्न
Give two evidences for presence of formyl group in glucose.
Draw a neat diagram for the following:
Haworth formula of glucopyranose.
Glucose on oxidation with dilute nitric acid gives _______________
Write the name of the unit to which glucose unit is linked to from sucrose.
Write chemical reaction for following conversions
glucose into gluconic acid
Classify the following carbohydrates into monosaccharide, disaccharide, oligosaccharide and polysaccharide:
glucose, cellulose, maltose, stachyose
What is the action of the following reagents on glucose?
acetic anhydride
Define carbohydrates.
By which of the following process formation of glycosidic bond occurs?
From the following identify an example of disaccharides.
Identify the substances having glycosidic bond and peptide bond, respectively in their structure:
Which of the following monosaccharides is a tetrose sugar?
______ is the prosthetic group of glycoproteins.
The reserve food material in animals is ____________.
From the following identify the materials that are made up of cellulose.
i. Plant cell wall
ii. Exoskeleton of arthropods
iii. Paper from plant pulp
iv. Cotton fibre
Identify the CORRECT combination.
Which element among the following is not present in saccharine?
The general formula for polysaccharide is ____________.
Which one of the following is Tetrose sugar?
Which one of the following carbohydrates is insoluble in water?
Which one of the following sugar does NOT have same empirical fonnula as that of carbohydrate?
Identify the number of secondary carbon atoms in glucose.
When 2 moles of stachyose is hydrolyzed, the number of moles of galactose obtained is ____________.
What is the quantity of glucose obtained when 68.4 g of sucrose is hydrolyzed in laboratory under ideal condition?
(Molar mass of sucrose = 342 g mol−1)
Which among the following reagents is used for conversion of glucose to glucoxime?
What is the molecular formula of glyceraldehyde?
Identify the product Y in the following reaction.
\[\ce{Maltose ->[Hydrolysis] X ->[dil. HNO3][(excess)] Y}\]
Which among the following is a product of hydrolysis of one mole raffinose?
How many optical isomers are possible for a compound having four asymmetric carbon atoms?
\[\ce{Glucose ->[(HCN)] Product ->[(hydrolysis)] Product ->[(HI + Heat)] A}\], the compound A is:
Assertion: A solution of sucrose in water is dextrorotatory. But on hydrolysis in the presence of little hydrochloric acid, it becomes levorotatory.
Reason: Sucrose hydrolysis gives equal amounts of glucose and fructose. As a result of this change in sign of rotation is observed.
Which of the following are epimers?
Why carbohydrates are generally optically active?
Classify the following into monosaccharides, oligosaccharides and polysaccharides.
Sucrose
Classify the following into monosaccharides, oligosaccharides and polysaccharides.
Lactose
Classify the following into monosaccharides, oligosaccharides and polysaccharides.
Maltose
Write the structure of α-D (+) glucopyranose.
Glucose on oxidation with bromine water yields gluconic acid. This reaction confirms the presence of ______.
A molecule of stachyose contains how many carbon atoms?
Which one is a non-reducing commercial sugar?
Formation of gluconic acid from glucose by oxidation using Br2 water.
Why carbohydrates are generally optically active?
Describe the action of the following reagent on glucose:
Bromine water
Write Fischer projection formulae for glucose.
Explain the hydrolysis of sucrose.
CH2 OH - CO - (CHOH)4 - CH2 OH is an example of ______.
Why carbohydrates are generally optically active.
The linkage present in Lactose is ______.
Why are carbohydrates generally optically active?
Why carbohydrates are generally optically active?
\[\ce{CH2OH - CO - (CHOH)4 - CH2OH}\] is an example of ______.
Why carbohydrates are generally optically active.
What are the number of chiral carbon atoms and the number of formyl groups, respectively, present in ribose?
