Atomic Life Reading Worksheet
Biology Core • Unit: Properties of Living Things Informational Reading
Atomic Life: Chemistry of Living Matter
How microscopic atoms and essential elements construct living systems
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1
Matter, Mass, and the Living World
Everything around you—from towering redwoods to single-celled bacteria and human tissue—is composed of matter, which is anything that has mass and takes up space. While living organisms perform unique functions like metabolism, growth, and reproduction, they do not possess special mystical materials. Living systems are constructed entirely from the exact same chemical elements that make up soil, oceans, and stars. Life is ordinary matter arranged in extraordinarily organized ways.
2
The Atom: Nature's Structural Unit
An atom is the smallest fundamental particle of an element that preserves its unique chemical properties. Atoms consist of three primary subatomic particles:
Proton (p⁺) +1 Charge
Found in nucleus. The number of protons defines elemental identity (atomic number).
Neutron (n⁰) 0 Charge
Found in nucleus alongside protons. Provides atomic mass and nuclear stability.
Electron (e⁻) -1 Charge
Orbits nucleus in energy shells. Governs chemical bonds, reactions, and energy transfer.
3
The CHNOPS Elements: Life’s Core Recipe
98%+ of Living Mass
Although the Periodic Table contains 118 elements, living things utilize just a small subset. Over 98% of human body mass is formed from six essential elements summarized by the acronym CHNOPS:
| Element | Symbol | % Mass | Primary Role in Organisms |
|---|
| Oxygen | O | ~65% | Major component of cellular water (H₂O); required for aerobic cellular respiration. |
| Carbon | C | ~18.5% | Forms 4 covalent bonds; forms the backbone of carbs, lipids, proteins, and DNA. |
| Hydrogen | H | ~9.5% | Present in water and all organic molecules; proton gradients generate ATP energy. |
| Nitrogen | N | ~3.2% | Key building block of amino acids (proteins) and nucleotide bases in DNA/RNA. |
| Phosphorus | P | ~1.0% | Forms cell membrane phospholipids, DNA sugar-phosphate backbones, and ATP. |
| Sulfur | S | ~0.3% | Forms disulfide bonds in amino acids (e.g., cysteine) to stabilize protein folding. |
4
Emergent Properties: From Inanimate to Alive
A single carbon atom is not alive. Neither is a molecule of water or a strand of protein. Life is an emergent property: new qualities arise as chemical components combine into increasingly complex levels of organization:
Atoms Molecules Organelles Cells (Life Emerges) Organism
Unit: Properties of Living Things • Introduction to Biochemistry Page 1 of 2 • Turn over for worksheet
Student Assessment & Practice Worksheet
Atomic Life: Analysis & Application
Use the informational reading on Page 1 to complete all questions below.
Score: / 25 pts
1 Part 1: Atomic Concepts & Structure
7 Points
1. Which subatomic particle is directly involved in forming chemical bonds, and why are these bonds essential for living organisms?
2. Why is carbon uniquely qualified to act as the primary "backbone" for life's complex macromolecules (carbohydrates, lipids, proteins, nucleic acids)?
2 Part 2: CHNOPS Data & Biological Roles
8 Points
3. Data Mystery: Oxygen makes up ~65% of human body mass, while carbon makes up only ~18.5%. Explain why oxygen accounts for so much more mass than carbon in living organisms.
4. Identify the specific CHNOPS element required for each biological structure:
Cell membrane phospholipids & ATP: Element:
Stabilizing disulfide bonds in folded proteins: Element:
3 Part 3: Application to the Properties of Life
10 Points
5. Emergent Properties: An isolated carbon or nitrogen atom is completely non-living. Explain how non-living atoms combine to produce living properties at the cellular level.
6. Astrobiology Connection: NASA planetary rovers testing Martian soil search for CHNOPS elements rather than directly seeking complex organisms. Why is this strategy scientifically sound?
Unit: Properties of Living Things • Introduction to Biochemistry Page 2 of 2 • Student Worksheet
