Which of the following bonds are formed by removal of water molecule ?
I. Peptide bond II. Glycosidic bond III phosphodiester bond IV. Hydrogen bonds

Options

A. I and II
B. II, III and IV
C. I , II and III
D. I , II and IV

Answer

To solve the question regarding which bonds are formed by the removal of a water molecule, we will analyze each bond type mentioned in the question:

### Step 1: Understand the Bonds
1. **Peptide Bond**: This bond is formed between two amino acids when the carboxyl group of one amino acid reacts with the amino group of another, resulting in the release of a water molecule (H2O). Thus, a peptide bond is formed through dehydration synthesis.

2. **Glycosidic Bond**: This bond occurs between two monosaccharides (sugar molecules) when they join together. Similar to the peptide bond, the hydroxyl group from one monosaccharide reacts with the hydroxyl group of another, releasing a water molecule. Therefore, glycosidic bonds are also formed via dehydration synthesis.

3. **Phosphodiester Bond**: This bond forms between nucleotides in nucleic acids (DNA and RNA). Specifically, the 3' hydroxyl group of one nucleotide reacts with the 5' phosphate group of another nucleotide, resulting in the elimination of a water molecule. Thus, phosphodiester bonds are also formed through dehydration synthesis.

4. **Hydrogen Bonds**: These bonds are different from the others. Hydrogen bonds occur due to the attraction between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom. They do not involve the removal of a water molecule during their formation. Therefore, hydrogen bonds are not formed by dehydration synthesis.

### Conclusion
Based on the analysis:
- **Peptide bond**: Yes, formed by removal of water.
- **Glycosidic bond**: Yes, formed by removal of water.
- **Phosphodiester bond**: Yes, formed by removal of water.
- **Hydrogen bonds**: No, not formed by removal of water.

### Final Answer
The bonds formed by the removal of a water molecule are:
- I. Peptide bond
- II. Glycosidic bond
- III. Phosphodiester bond