# What nonmetals are essential to life?

Sep 20, 2015

The essential nonmetallic elements are $\text{H}$, $\text{B}$, $\text{C}$, $\text{N}$, $\text{O}$, $\text{Si}$, $\text{P}$, $\text{S}$, $\text{Cl}$, $\text{Se}$, $\text{Br}$, and $\text{I}$ (and possibly $\text{As}$).

#### Explanation:

The 28 elements deemed essential to life include at least 12 nonmetals.

Living organisms are made of organic compounds, so carbon and hydrogen are included.

Carbohydrates contain oxygen, and where would we be without the phosphorus in phospholipids and ATP.

We couldn't have amino acids and proteins without nitrogen.

And these must include the sulfur in methionine and cysteine.

Selenium is a constituent of more than two dozen proteins that play critical roles in reproduction, thyroid hormone metabolism, and DNA synthesis.

Chlorine as chloride ion is an essential component of most bodily fluids.

Iodine is essential to life. It is part of the thyroxine molecule, a thyroid gland hormone that controls growth.

Boron is required for the maintenance of bone and normal blood levels of estrogen and testosterone.

Silicon is necessary for molecules that are involved in bone formation, cartilage composition, and cartilage calcification.

Bromine as is the most recent addition to the list of essential nonmetals. The bromide ion is a cofactor that enables an enzyme involved in the formation of collagen.

Arsenic is close to qualifying as an essential element. It appears to be involved in the metabolism of methionine, but its importance in humans has not yet been proved.