Single-celled organisms need the following to survive

A single cell needs several elements to live, like carbon, hydrogen, oxygen, nitrogen, which are found almost everywhere. But not every cell can collect all these elements or build all of the molecules it needs to live.

Depending on their ability to produce energy and biomolecules, organisms an be divided into primary nutritional groups. They tell us which sources of energy, electrons and matter a cell uses. I advise you to read this Wikipédia article, which explains it well. I will try to summarize it for you.

If the source of energy (i.e. the electron donor in the respiration chain) is an inorganic compound, the organism is lithotroph. When it is organic, he organism is called organotroph. Also, when the organism :

Needs light (energy) and organic carbon (matter) → Photoheterotroph

Needs light and inorganic carbon → Photoautotroph (example : algae can photosynthetize to produce energy and attach carbon dioxide to biomolecules)

Oxydates molécules (also energy) and needs organic carbon → Chemoheterotroph (the unicellular eukaryote paramecium eats bacteria as a food and energy source) Oxydates molecules to produce energy and needs inorganic carbon → Chemoautotroph (some bacteria, apparently ^^)

The bacteria Nitrobacter, which lives in the soil, uses nitrites as an elecron donor, decomposes dead organic matter as a source of energy, and attaches carbon dioxide within its Calvin cycle. It is a chemolithoautotrophe.

On top of that, proteins are built out of around 20 amino acids, and depending on its DNA and its metabolism, not every cell can synthetize all of them, but each one does need them !

I hope this helped you :)