There is one interesting feature here. In primitive organisms, for example, bacteria, coding regions occupy more than 88% of the genome.
This means that almost the entire bacterial genome has functions.
In vertebrates, including humans, the situation is different.
The non-coding part of human DNA is about 98%, that is, the ratio of non-coding regions is much higher than the number of genes encoding proteins.
Different organisms, but their hereditary apparatus unites them.
The non-coding DNA of eukaryotes can vary widely, even between closely related sequences.
Most of the differences are due to a decrease or increase in repetitive DNA, not the number of genes. Therefore, some researchers have suggested that repetitive DNA is junk DNA.
There is no need for such sequences in the simplest organisms, since they are represented by one cell, and it is wasteful for them to have a large genome.
A necessary condition for life is energy.
Every organism, every living thing adapts as best it can, finding different sources of energy: be it its own resources or something else. Energy gives life.
For example, plants use the energy of the sun. During photosynthesis, complex substances are formed from inorganic substances (carbon dioxide and water) due to visible light.
As a result of photosynthesis, glucose is formed, which then participates in complex biochemical processes with the formation of macroergic molecules.
Microorganisms by the source of nutrition are phototrophs that use the energy of sunlight for biosynthetic reactions and chemotrophs that obtain energy by oxidizing inorganic substances and organic compounds.
It is clear that energy is needed for the vital activity of each individual cell.
How a living eukaryotic cell provides itself with the energy it needs is still unknown to the end.
Of course is important, the role of macroergic and other molecules that can store energy in various reactions.
For example, deoxyribonucleoside triphosphates (ATP, ATP, GTP, CTF) are a source of energy in such an important process as DNA replication. Other molecules also perform similar functions. But this is a small particle for a living cell, for its existence.