All questions of Carbohydrates and Glycobiology for ACT Exam

Yes bcz only aldehyde group gives silver mirror test.

Glucose gives Fehling’s test.

Hydrolysis of sucrose is inversion because the angle of specific rotation of the plane polarized light changes from positive to negative value due to the presence of optical isomers of mixture of glucose and fructose sugar...

It forms glucose pentaacetate. The acetic anhydride esterifies with all the alcohol groups on the glucose ring.

Lactose intolerance is the inability to break down a type of natural sugar called lactose. Lactose is commonly found in dairy products, such as milk and yogurt. A person becomes lactose intolerant when his or her small intestine stops making enough of the enzyme lactase to digest and break down the lactose.

All sacchrides /carbohydrates form glycosidic bond by eliminating water molecule

Glucose and C2 of fructose, which does not have a free aldehyde or ketone group to undergo oxidation and reduction reactions.
c)Sucrose does not react with Benedict's reagent, which is used to detect the presence of reducing sugars.
d)Sucrose cannot be hydrolyzed by acid or enzyme into its constituent monosaccharides.

Non-reducing sugars do not have an OH group attached to the anomeric carbon so they cannot reduce other compounds. All monosaccharides such as glucose are reducing sugars. A disaccharide can be a reducing sugar or a non-reducing sugar. Maltose and lactose are reducing sugars, while sucrose is a non-reducing sugar.

It shows that glucose exists as n-hexane...i.e. it has straight linear chain...

It is called invert sugar because the angle of the specific rotation of the plain polarized light changes from a positive to a negative value due to the presence of the optical isomers of the mixture of glucose and fructosesugars.

Introduction:
Polysaccharides are complex carbohydrates composed of repeating units of monosaccharides. These monosaccharides are linked together by a specific type of bond known as the glycosidic linkage. The glycosidic linkage is a covalent bond formed between the anomeric carbon of one monosaccharide and a hydroxyl group on another monosaccharide. It is the key structural feature that gives polysaccharides their unique properties and functions.

Explanation:
The correct answer is option 'D', the glycosidic linkage. Let's understand why this is the correct answer and explore the other options:

1. Peptide linkage:
- Peptide linkages are covalent bonds that connect amino acids to form proteins.
- Polysaccharides are not formed by peptide linkages, so this option is incorrect.

2. Glycogen linkage:
- Glycogen is a storage polysaccharide found in animals, including humans.
- While glycogen is composed of glucose monomers, the linkage connecting these monomers is the glycosidic linkage, not the glycogen linkage.
- Therefore, this option is incorrect.

3. Nucleosidic linkage:
- Nucleosidic linkages are covalent bonds that connect nucleotides to form nucleic acids, such as DNA and RNA.
- Polysaccharides are not formed by nucleosidic linkages, so this option is incorrect.

The Glycosidic Linkage:
The glycosidic linkage is a specific type of covalent bond formed between the anomeric carbon of one monosaccharide and a hydroxyl group on another monosaccharide. It is formed through a condensation reaction, where a molecule of water is eliminated.
- The anomeric carbon is the carbon atom that is involved in forming the ring structure of a monosaccharide.
- The hydroxyl group can be located on a different monosaccharide or on the same monosaccharide, resulting in different types of glycosidic linkages.

Properties and Functions:
The glycosidic linkage plays a crucial role in determining the properties and functions of polysaccharides:
- The type of glycosidic linkage determines the structure and shape of the polysaccharide molecule.
- It affects the solubility, digestibility, and stability of the polysaccharide.
- Different types of glycosidic linkages result in different polysaccharides with distinct functions, such as energy storage (e.g., starch, glycogen) or structural support (e.g., cellulose, chitin).

Conclusion:
In polysaccharides, the linkage connecting monosaccharides is called the glycosidic linkage. This covalent bond is formed between the anomeric carbon of one monosaccharide and a hydroxyl group on another monosaccharide. The glycosidic linkage determines the structure, properties, and functions of polysaccharides.

Lactose is the carbohydrate that is commonly known as milk sugar. It is a disaccharide composed of two sugar molecules, galactose and glucose, linked together by a β-glycosidic bond. Lactose is found in the milk of mammals, including humans, and is an important source of energy for infants.

Here is a detailed explanation of why lactose is called milk sugar:

Lactose in Milk:
- Lactose is primarily found in the milk of mammals. It is the main carbohydrate present in milk, accounting for about 4-5% of its composition.
- It provides energy for the growing infant and is essential for their development.
- As mammals produce milk to nourish their young, lactose is present in varying amounts in the milk of different species, including humans.

Structure of Lactose:
- Lactose is a disaccharide, which means it is composed of two sugar molecules linked together.
- It consists of one molecule of glucose and one molecule of galactose.
- The glucose and galactose molecules are joined by a β-glycosidic bond, which is a specific type of chemical bond between the two sugars.

Digestion of Lactose:
- Lactose is digested by the enzyme lactase, which is produced in the small intestine.
- Lactase breaks down lactose into its individual sugar components, glucose and galactose.
- These simple sugars can then be absorbed into the bloodstream and used as a source of energy by the body.

Intolerance to Lactose:
- Some individuals have a reduced ability to produce lactase, resulting in lactose intolerance.
- Lactose intolerance is characterized by symptoms such as bloating, gas, and diarrhea after consuming milk or dairy products.
- This occurs because undigested lactose reaches the large intestine, where it is fermented by bacteria, leading to the production of gas and other byproducts.

In conclusion, lactose is called milk sugar because it is the main carbohydrate found in milk. It consists of glucose and galactose linked together by a β-glycosidic bond. Lactose provides energy for infants and is digested by the enzyme lactase. Lactose intolerance can occur when there is a reduced ability to produce lactase, leading to digestive symptoms after consuming milk or dairy products.

Because it is in the ratio of 1:2:1

Here first of all we see that this compound has anomeric carbon at C2 thus it is a fructose. Now since first hydroxyl is at the bottom, yeah starting from right always as usual this is similar to the fish configuration hence alpha you see its a logic (or say rtafication) that alpha appears as a fish(α) and lives in sea ie bottom, while beta appears as bird(β) lives on top, try to draw symbols of alpha and beta to see alpha appears fish and so. Hope this helps.