Which of the following type of bond is not present in the teiary structure of protein?
**Core Concept**
The tertiary structure of a protein refers to its 3D shape, which is stabilized by various types of chemical bonds. Understanding the different types of bonds that contribute to protein structure is essential in biochemistry and molecular biology.
**Why the Correct Answer is Right**
The correct answer is a covalent bond. Covalent bonds involve the sharing of electron pairs between atoms, resulting in a strong and stable chemical bond. However, covalent bonds are not typically found in the tertiary structure of proteins. Instead, the tertiary structure is stabilized by non-covalent interactions, such as hydrogen bonds, ionic bonds, and van der Waals forces.
**Why Each Wrong Option is Incorrect**
* **Option A:** Hydrogen bonds are a type of non-covalent interaction that play a crucial role in stabilizing the tertiary structure of proteins. They form between the hydrogen atom of one molecule and the electronegative atom of another molecule.
* **Option B:** Ionic bonds are also a type of non-covalent interaction that contribute to the stability of the tertiary structure of proteins. They form between positively and negatively charged amino acid residues.
* **Option C:** Van der Waals forces are a type of non-covalent interaction that contribute to the stability of the tertiary structure of proteins. They arise from the temporary dipoles that form in non-polar molecules.
**Clinical Pearl / High-Yield Fact**
Remember that the stability of the tertiary structure of proteins is primarily maintained by non-covalent interactions, which are reversible and can be disrupted by changes in temperature, pH, or ionic strength.
**Correct Answer:** D. Covalent bond.