All life is chemistry. ~ Belgian chemist Jan van Helmon
Organic chemistry is the chemistry of carbon compounds. Biochemistry is the study of carbon compounds that crawl. ~ Mike Adam
Life sustains itself by chemical energy. Transformative sustenance transpires in water.
Clean water is vital for all known life. Mars may have never evolved life because the salinity of its water has long exceeded levels by which life could arise, survive, or thrive.
Humans are 65–90% water, scaffolded by carbon-containing organic molecules. 99% of human body mass comprises 6 elements: oxygen (65%), carbon (18%), hydrogen (10%), nitrogen (3%), calcium (1.4%), and phosphorous (1.1%). By contrast, aluminum and silicon are abundant in Earth’s crust but rare in life forms.
Carbon’s unsurpassed flexibility lends itself to complexity. Sturdy nitrogen provides stability. Oxygen and hydrogen readily react, and so make excellent elements for cellular activity. Being readily reactive, calcium ions play a central role in many cellular functions, and in intercellular communication. As a store of energy, phosphorous is vital to metabolism. 2 more elements are noteworthy for their organic roles: potassium and sulfur. Potassium (0.4%) assists in homeostasis and cellular communication. Through its surfeit of electrons which willingly shuffle, sulfur (0.3%) helps catalyze reactions.
All told, cells make a living using just 30 different monomers (molecule types).
The characteristics of a cell rest on the structure of its molecular components. ~ French biologist François Jacob
The molecular components of organisms are remarkably uniform in the nature of the components, as well as in the ways in which they are assembled and used. ~ Spanish American biologist Francisco Ayala