What are the four forces acting on amino acids placed in water?

Answer 1

1. Van der Waals forces: the natural stickiness of each individual atom, caused by the movement of its electron cloud. While small, this effect can be substantial when two molecules can line up close to one another.

2 Electrostatic charge: the ions of a side chain that have either plus or minus charge. In a charged side chain, an atom has either lost an electron and become a positive ion or gained an electron, and becomes a negative ion.

3. S-S bonds: Several sulfur (S) - containing amino acids, such as cystein, located in the different parts of the protein chain, interact with each other, making covalent bonds that link two different parts of a protein molecule together. They often form loops in the otherwise straight chains. Every S-S bond made between two molecules of cysteine serves as a "staple" holding the shape in a more steady position. (See the S-S bond in Fig. 2) This covalent bond is not as strong as the peptide bond between amino acids, and breaks when heated, though at a temperature lower than that required to break the peptide bonds making the protein chain.

4. Hydrogen bonds: Because the water molecule's oxygen is strong, it pulls the electron cloud away from its two hydrogen, making its hydrogen slightly positive and therefore capable of interacting with negative poles on neighboring molecules.