Amino acids are the building blocks of the body's worker molecules called proteins. When two amino acids bond together, they do so through the formation of a peptide linkage, and a dipeptide is formed. Consider the following tripeptide formed when three alanine amino acids bond together: What types of interparticle forces could be present in a sample of this tripeptide?

Alanine is an α-amino acid with the general chemical formula \(NH_2CH(CH_3)COOH\). It consists of an amino group \((-NH_2)\), a carboxyl group \((-COOH)\), and a side chain methyl group \((-CH_3)\), all attached to a central carbon atom, also known as the α-carbon.

A peptide bond is formed when the amino group of one amino acid reacts with the carboxyl group of another amino acid, releasing a molecule of water in the process. In the given exercise, three alanine amino acids are bonded together to form a tripeptide. So, there will be two peptide bonds formed in this process, and the general formula of the tripeptide will look like this: \(NH_2CH(CH_3)CONHCH(CH_3)CONHCH(CH_3)COOH\).

Now that we know the structure of the tripeptide formed by three alanine amino acids, we can identify the different types of interparticle forces that could be present in a sample of this tripeptide. 1. Hydrogen Bonding: The peptide bonds formed between the amino acids have hydrogen atoms bonded to highly electronegative oxygen and nitrogen atoms. This creates regions of partial positive and negative charge, allowing for hydrogen bonding. 2. Dipole-Dipole Interactions: The polar peptide bonds in the tripeptide create regions of partial positive and negative charges. This leads to dipole-dipole interactions between the tripeptide molecules. 3. London Dispersion Forces: The tripeptide molecules are non-linear and have regions of temporary induced dipoles that can interact with neighboring molecules, leading to London dispersion forces. Conclusion: In a sample of the tripeptide formed by three alanine amino acids, the interparticle forces present are hydrogen bonding, dipole-dipole interactions, and London dispersion forces.