Living things are made of types of molecules, known as macromolecules.
There are four major classes of biological macromolecules:
carbohydrates
lipids
proteins
nucleic acids
Each of these types of macromolecules performs a wide array of important functions within the cell; a cell cannot perform its role within the body without many different types of these crucial molecules. In combination, these biological macromolecules make up the majority of a cell’s dry mass. (Water molecules make up the majority of a cell’s total mass.) All the molecules both inside and outside of cells are situated in a water-based (i.e., aqueous) environment, and all the reactions of biological systems are occurring in that same environment.
Inside the seed there are is an embryo the baby plan and cotyledons. When the seed begins to grow, one part of the embryo becomes the plant while the other part becomes the root of the plant.
