Home / AP Biology : 1.1 Structure of Water and Hydrogen Bonding – Study Notes

AP Biology : 1.1 Structure of Water and Hydrogen Bonding – Study Notes

A. Elements

➢ All life forms made up of matter

    • All matter made up of elements
              ■ Elements
                          ● Substances that cannot be broken down into smaller substances by chemical means

B. Essential Elements of Life

➢ 96% of the mass of all living things made up of 4 elements:

  •  $\text{Oxygen (O)}$
  • $\text{Carbon (C)}$
  • $\text{Hydrogen (H)}$
  • $\text{Nitrogen (N)}$

➢ Other elements (collectively 4% of biomass)

  • $\text{Calcium (Ca)}$
  • $\text{Phosphorus (P)}$
  • $\text{Potassium (K)}$
  • $\text{Sulfur (S)}$
  • $\text{Sodium (Na)}$
  • $\text{Chlorine (Cl)}$
  • $\text{Magnesium (Mg)}$

➢ Trace elements

  • $\text{Iron (Fe)}$
  • $\text{Iodine (I)}$
  • $\text{Copper (Cu)}$
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