Inorganic Ions
- Understand the role in plants of:
- Nitrate ions - to make DNA and amino acids
- Calcium ions - to form calcium pectate for the middle lamellae
- Magnesium ions - to produce chlorophyll
- Phosphate ions - to make ADP and ATP
Ionic Bonding:
The atoms involved in the reaction donate or receive electrons. The atom, or part of the molecule, gains one or more electrons and becomes a negative ion (anion). The other atom, or part of the molecule, loses one or more electrons and becomes a positive ion (cation). Strong forces of attraction called ionic bonds hold the oppositely charged ions together.
Covalent Bonding:
The atoms involved in the reaction share electrons. Covalent bonds are very strong and the molecules formed are usually neutral. However, in some covalent compounds the molecules are slightly polarised. The electrons in the covalent bonds are not quite evenly shared. This means the molecule has a part that is slightly negative and a part that is slightly positive. This separation of charge is called a dipole, and the tiny charges are represented as x+ and x-. The molecule is described as a polar molecule. This polarity is particularly common if one or more hydrogen atoms are involved in the bond.
Inorganic Ions
Cells are 60% - 70% water , and so in living organisms, most ionic substances, exist as positive and negative ions. Many of these ions play specialised roles in individual cells and ion the function of entire organisms.
Anions
Nitrate Ions NO₃− Needed in plants for the formation of amino acids and therefore proteins from the products of photosynthesis, and also for the formation of DNA
Phosphate Ions PO4^3- Needed in all living organisms including plants and animals in the formation of ATP, ADP, DNA and RNA
Chloride Ions Cl- Needed in nerve impulses,sweating and many secretory systems
Hydrogen Carbonate ions HCO₃− Needed for buffering the blood to prevent it from becoming too acidic
Cations
Sodium Ions Na+ Needed in nerve impulses. sweating and many secretory systems
Calcium Ions Ca^2+ Needed for the formation of calcium pectate for the middle lamella between two cell walls in plants, and for bone formation and muscle contraction in animals
Hydrogen Ions H^+ Needed in cellular respiration and photosynthesis, and in numerous pumps and system in organisms as well as pH balance
Magnesium Ions Mg^2+ Needed for production of chlorophyll in plants
Anions
Nitrate Ions NO₃− Needed in plants for the formation of amino acids and therefore proteins from the products of photosynthesis, and also for the formation of DNA
Phosphate Ions PO4^3- Needed in all living organisms including plants and animals in the formation of ATP, ADP, DNA and RNA
Chloride Ions Cl- Needed in nerve impulses,sweating and many secretory systems
Hydrogen Carbonate ions HCO₃− Needed for buffering the blood to prevent it from becoming too acidic
Cations
Sodium Ions Na+ Needed in nerve impulses. sweating and many secretory systems
Calcium Ions Ca^2+ Needed for the formation of calcium pectate for the middle lamella between two cell walls in plants, and for bone formation and muscle contraction in animals
Hydrogen Ions H^+ Needed in cellular respiration and photosynthesis, and in numerous pumps and system in organisms as well as pH balance
Magnesium Ions Mg^2+ Needed for production of chlorophyll in plants