Biological moelcules

3.1 - Biological elements

• Covalent bond forms between a shared pir of electrons
• The electrons used to form covalent bonds are unpaired and present in the outer orbitals of the element
• Inonic bonds form when one atom donates an electron and the other atom recieves it
• This forms opositely charged ions (as electrons ahve a negative charge) which are bonded by electrostatic attraction
• Ions in solutions are called electrolytes
• Uses of Cations:

Ca²⁺ for nerve impulse transmission and muscle contraction

Na²⁺ for nerve impulse…