Which one is covalent bond ?

Options

A. Peptide bond
B. Phosphodiester bond
C. Both correct
D. Both wrong

Answer

To determine which option represents a covalent bond, we will analyze the given options one by one.

### Step 1: Understand the options
The options provided are:
- A) Peptide bond
- B) Phosphodiester bond
- C) Both correct
- D) Both wrong

### Step 2: Define the bonds
1. **Peptide Bond**: This is a covalent bond that links amino acids together in proteins. It forms between the carboxyl group of one amino acid and the amino group of another, releasing a molecule of water (condensation reaction).

2. **Phosphodiester Bond**: This bond connects the 5' carbon of one deoxyribose sugar to the 3' carbon of another in the backbone of DNA or RNA. It involves a phosphate group and is a type of covalent bond.

### Step 3: Identify the covalent bond
- The peptide bond is indeed a covalent bond.
- The phosphodiester bond is also a covalent bond.

### Step 4: Evaluate the options
- Option A (Peptide bond) is a covalent bond.
- Option B (Phosphodiester bond) is also a covalent bond.
- Therefore, both A and B are correct.

### Step 5: Conclusion
The correct answer is **C) Both correct**, as both the peptide bond and the phosphodiester bond are types of covalent bonds.

---