Elements of Life
Introduced| English |
|---|
| elements/ˈelɪmənts/ |
| carbon/ˈkɑːbən/ |
| trace elements/treɪs ˈelɪmənts/ |
Life from a short list
- Everything alive is built from just a handful of the periodic table's elements.
- The same few elements appear in a bacterium, an oak tree, and you.
- A tiny set does almost all the work — and one element leads them all.
- Understanding which elements matter explains what living molecules are made of.
The big four: CHON
- About 96% of a living body is just four elements 元素: carbon, hydrogen, oxygen, nitrogen.
- Oxygen and hydrogen are mostly locked up in water.
- Nitrogen appears in every protein and every nucleic acid.
- Remember them as CHON — the core of life's chemistry.
Four elements make up about 96% of a living body. Which are they?
Carbon, hydrogen, oxygen and nitrogen (CHON) make up about 96% of living matter.
Carbon is the star
- Carbon 碳 has four outer electrons, so it forms four strong covalent bonds.
- That lets carbon link into long chains, branches, and rings.
- These carbon skeletons are the frames of every large biological molecule.
- No other common element is so versatile at building structure.
How many covalent bonds can one carbon atom form?
Carbon has four outer electrons, so it forms four bonds — letting it build long chains, branches and rings.
Phosphorus and sulfur are added to CHON to make "CHNOPS". Where is phosphorus especially important?
Phosphorus forms the phosphate groups in DNA, RNA and the energy carrier ATP.
P, S, and the trace elements
- Add phosphorus and sulfur to CHON and you get CHNOPS — the six main elements.
- Phosphorus builds the phosphate groups in DNA, RNA, and ATP.
- Sulfur helps hold many proteins in shape.
- A handful of trace elements 微量元素 (iron, iodine, calcium…) are needed in tiny amounts but are still essential.
Major or trace element?
Sort elements by how much of a living body they make up. A few elements dominate; others are vital in tiny amounts.
A trace element is unimportant because the body needs so little of it.
Trace elements are needed in tiny amounts but are still essential — iron carries oxygen, iodine makes thyroid hormones.
Select all true statements about the elements of life.
Life is built from light elements — mainly CHNOPS — not precious metals.
"Trace" does not mean unimportant. A trace element is needed in a tiny quantity, yet life fails without it — too little iron and blood cannot carry oxygen; too little iodine and the thyroid cannot work.
Iron: a tiny amount, a huge job.
- Iron makes up a vanishingly small fraction of your body mass.
- Yet every haemoglobin molecule needs iron to grip oxygen.
- Without that trace of iron, your blood could not carry oxygen to your cells.
Living things are built mostly from a few light elements — carbon, hydrogen, oxygen, and nitrogen (CHON), plus phosphorus and sulfur (CHNOPS). Carbon's four bonds let it build large molecules. A few trace elements are needed in tiny amounts but are still essential.