Macromolecules are like massive giga gobstoppers, made up of heaps of atoms (over 10,000 atomic mass units!). They come in different types, each essential to life as we know it - you've got your polysaccharides, your polypeptides, and your nucleic acids, all big hitters in the world of biology.

Macromolecules are put together from smaller units, the monomers (think of them like Lego blocks). When you connect these monomers together in a chain, you get a polymer. It's like creating a super long Lego masterpiece, starting with one block at a time!

When monomers get linked to form a polymer, a magical process called a condensation reaction takes place. Picture this: Two molecules are hanging out, they decide to form a bond and voila, they create a new molecule - water! How? By losing a hydroxyl group (-OH) from one molecule and a hydrogen atom from the other. It's like shaking hands, but you lose a glove in the process.

Constructing these hefty macromolecules isn't a breeze - it requires energy, and that's where ATP (Adenosine Triphosphate) comes in. ATP acts like the battery that powers the construction of polysaccharides, polypeptides, and nucleic acids. Imagine you're building a skyscraper (the macromolecule). You'd need electricity (ATP) to power your tools and machinery!