Recall What are some macromolecules that have hydrogen bonds as a part of their structures?

Proteins are one of the fundamental macromolecules in biological systems. They are composed of long chains of amino acids folded into specific structures. Hydrogen bonds play a crucial role in stabilizing these structures.

For example, in the secondary structure of proteins, hydrogen bonds occur between the backbone atoms. This bonding pattern leads to the formation of alpha helices and beta sheets which are common structural motifs. The alpha helix structure is held together by hydrogen bonds between the carbonyl oxygen of one amino acid and the amide hydrogen of another, four residues down the chain.

Similarly, in beta sheets, hydrogen bonds form between adjacent strands. These hydrogen bonds help maintain the sheet-like structure of proteins.

Overall, hydrogen bonds are essential for maintaining the structural integrity and functional capabilities of proteins.

DNA, or deoxyribonucleic acid, is the hereditary material in all living organisms. One of the key features of DNA structure is its double helix formation, which is stabilized by hydrogen bonds between complementary base pairs.

The base pairs in DNA are adenine (A) pairing with thymine (T), and cytosine (C) pairing with guanine (G). Hydrogen bonds are essential for these pairings:

• A-T pairs form through two hydrogen bonds
• C-G pairs are stabilized by three hydrogen bonds

These hydrogen bonds contribute to the zipping together of the two DNA strands, ensuring the molecule's stability and its ability to replicate accurately.

Importantly, the specificity of hydrogen bond formation between the base pairs ensures accurate transmission of genetic information during DNA replication and transcription.

Carbohydrates are macromolecules that include sugars, starches, and fibers. A significant class within carbohydrates is polysaccharides, which are long chains of monosaccharide units bonded together.

Hydrogen bonds are prominent in polysaccharides and contribute to their structure and function. For example, in cellulose, which is a structural polysaccharide found in the cell walls of plants, hydrogen bonds form between adjacent chains. This results in a strong, fibrous structure that provides tensile strength.

Similarly, in starch, which is an energy storage polysaccharide in plants, hydrogen bonds help in the formation of helical structures. These helices are compact and efficient for storing energy.

Thus, hydrogen bonds are critical in giving polysaccharides their distinctive properties, whether it's providing structural support or storing energy.