Monosaccharides: Overview, Questions, Preparation

A: Monosaccharides are the only simplest units of carbohydrates and they are the simplest form of sugar. In other words, It is the most basic form of carbohydrates. They are made up of hydrogen, carbon and oxygen atoms. They are the building blocks of more complex carbohydrates i.e., they can join together and form complex carbohydrates.

For example:

1. Monosaccharides form
2. 3-10 of them form
3. 11 or more of them form

Monosaccharides are used to produce and store energy. Most organisms create energy by breaking down the monosaccharide glucose and harvesting the energy released from the bonds. Other Monosaccharides are used to form long fibers, which can be used as a form of cellular structure.

Examples of Monosaccharides are glucose, fructose, and galactose.

A: (i) 1.Ribose, 2-deoxyribose, galactose, and fructose are

Monosaccharides are the simplest units of carbohydrates which cannot be hydrolyzed into simpler compounds.

(ii) Maltose and lactose are

A disaccharide is a carbohydrate that is formed when two monosaccharides are joined together and a molecule of water is removed from the structure. Lactose is a disaccharide formed from the combination of galactose and glucose.

A: All those carbohydrates which reduce Fehling’s solution to red precipitate of Cu₂O or Tollen’s reagent to metallic Ag is called reducing sugars. All monosaccharides (both aldoses and ketoses) and disaccharides except Sucrose are reducing sugars.

A: Glucose and sucrose are carbohydrates (optically active polyhydroxy aldehydes or ketones). 
Structure of glucose:

Structure of sucrose:

As you can see both the compounds have five –OH and eight –OH groups respectively. These –OH groups are responsible for the extensive hydrogen bonding with water. This –H bonding is responsible for the solubility of glucose and sucrose in water.

In case of cyclohexane or benzene (simple six-membered ring compounds) , they do not contain any – OH groups. Hence, they cannot undergo –H bonding with water and are insoluble.

A:

A 14.4 Amino acids are organic compounds containing amine (basic) and carboxyl (acidic) functional group with a specific side chain. Both acidic and basic group are present in the same molecule. In, aqueous solution carboxyl group can lose a proton (H⁺) and amino group can accept a proton (H⁺) giving rise to the dipolar ion called as zwitter ion. Zwitter ion is shown below:

In this zwitter ion there is the presence of both positive as well as negative charge, so there is the development of strong electrostatic force of attraction between the molecules and the water. For this reason solubility of amino acids is higher. Due to strong electrostatic interaction there is formation of strong bond between them, hence the melting point of amino acid is higher than the halo acids (as they do not exhibit such dipolar behaviour).

A: The three monosaccharides which are essential in nutrition are glucose, fructose, and galactose.

A: Two three-carbon trioses are the simplest monosaccharides: glyceraldehyde, an aldose, and dihydroxyacetone, a ketose.

A: Fructose is a basic ketonic monosaccharide, or fruit sugar, and the sweetest sugar present in many plants where disaccharide sucrose is also bound to glucose to form.

A: Although most beverages that are commonly sold in supermarkets contain abnormally elevated sugar content, orange juice generally does not. Orange juice is made of other potentially beneficial ingredients and a mixture of fructose, glucose, and sucrose is the sugar found in orange juice.

A: There is only one subunit of sugar in the monosaccharides, and they constitute the essential units of all carbohydrates. Hence it is a monosaccharide.