Chemical Level of Organisation

🃏 Card 1 – Hierarchical Overview (Big Picture)

❓ Q: What is the structural hierarchy of the human body from smallest to largest?

✅ A:

Atom → Molecule → Cell → Tissue → Organ → Organ System → Organism

🃏 Card 2 – Define Matter

❓ Q: What is matter?

✅ A:

Anything that:

  • Has mass

  • Takes up space

Everything in the human body is made of matter.

🃏 Card 3 – What is an Atom?

❓ Q: Define an atom.

✅ A:

The smallest stable unit of matter.

It consists of:

  • Protons (+)

  • Neutrons (0)

  • Electrons (–)

🃏 Card 4 – Structure of an Atom

❓ Q: Where are the subatomic particles located?

✅ A:

  • Protons → nucleus

  • Neutrons → nucleus

  • Electrons → orbit around nucleus

🃏 Card 5 – Why Are Electrons So Important?

❓ Q: Why are electrons critical in chemistry?

✅ A:

  • They determine chemical reactivity

  • They form chemical bonds

  • They can be shared, gained, or lost

  • They allow formation of molecules & ions

Electrons drive ALL chemical reactions in the body.

🃏 Card 6 – Define Element

❓ Q: What is an element?

✅ A:

A substance made of only one type of atom.

Example:

  • Hydrogen (H)

  • Oxygen (O)

🃏 Card 7 – What Determines an Element?

❓ Q: What determines which element an atom is?

✅ A:

The number of protons in the nucleus
→ This is called the atomic number

🃏 Card 8 – The 5 Fundamental Organic Elements

❓ Q: What are the five fundamental elements that make up biomolecules?

✅ A:

  • Carbon (C)

  • Hydrogen (H)

  • Oxygen (O)

  • Nitrogen (N)

  • Phosphorus (P)

Together they make up ~99% of body mass.

🃏 Card 9 – Most Abundant Element in the Body

❓ Q: What is the most abundant element in the human body?

✅ A:

Oxygen (~65% of body weight)

Followed by:

  • Carbon

  • Hydrogen

  • Nitrogen

  • Calcium

  • Phosphorus

🃏 Card 10 – Define Molecule

❓ Q: What is a molecule?

✅ A:

Two or more atoms bonded together.

They may be:

  • Same element (O₂)

  • Different elements (CO₂)

🃏 Card 11 – Define Compound

❓ Q: What is a compound?

✅ A:

A molecule made of two or more different elements bonded together.

⚠ Key rule:

  • All compounds are molecules

  • Not all molecules are compounds

🃏 Card 12 – Molecule vs Compound (Visual Comparison)

❓ Q: What is the difference between a molecule of an element and a compound?

✅ A:

  • Molecule of element → same atoms bonded (O₂)

  • Compound → different atoms bonded (CO₂)

🃏 Card 13 – What is a Mixture?

❓ Q: What is a mixture?

✅ A:

A combination of:

  • Atoms

  • Molecules

  • Compounds

Not chemically bonded together.

The human body is chemically a complex mixture.

🃏 Card 14 – What is an Ion?

❓ Q: How is an ion formed?

✅ A:

When an atom:

  • Gains electrons → negative ion

  • Loses electrons → positive ion

Ions are critical in:

  • Nerve impulses

  • Muscle contraction

🃏 Card 15 – Application Card (Exam Style)

❓ Q: If an atom has 8 protons, what determines its chemical behaviour?

✅ A:

Its electrons, particularly:

  • Number of outer shell electrons

  • Whether they are shared, gained, or lost

Protons determine identity.
Electrons determine behaviour.