What type of bonds are formed when monosaccharides form cyclic hemiacetals?

• A. $\text{Glycosidic bonds}$
• B. $\text{Ionic bonds}$
• C. $\text{Hydrogen bonds}$
• D. $\text{Covalent bonds}$

Answer: (D)

Verified step by step guidance

1. Understand the structure of monosaccharides: Monosaccharides are simple sugars that can exist in linear or cyclic forms. The cyclic form is often a result of the reaction between the aldehyde or ketone group and a hydroxyl group within the same molecule.
2. Identify the functional groups involved: In the formation of cyclic hemiacetals, the aldehyde or ketone group reacts with an alcohol group. This is an intramolecular reaction, meaning it occurs within the same molecule.
3. Recognize the type of bond formed: When the aldehyde or ketone group reacts with the alcohol group, a new covalent bond is formed. Specifically, this is a single covalent bond between the carbon of the carbonyl group and the oxygen of the hydroxyl group.
4. Differentiate from other bond types: Glycosidic bonds are formed between monosaccharides to create disaccharides or polysaccharides, not in the formation of cyclic hemiacetals. Ionic bonds involve the transfer of electrons and are typically found in salts, while hydrogen bonds are weak interactions between molecules.
5. Conclude with the nature of the bond: The formation of cyclic hemiacetals in monosaccharides involves the creation of covalent bonds, which are strong and involve the sharing of electron pairs between atoms.