Chemistry For Life Flashcards
What is ionic bonding?
When atoms donate or receive electrons
What is an anion?
Has gained electrons therefore is a negative ion
What is a cation?
Has lost electrons therefore is a positive ion
What is covalent bonding?
When the atoms involved in the reaction share electrons
What is a dipole?
When part of a molecule is slightly positive and part is slightly negative resulting in a separation of charge. This molecule is called a polar molecule
Important anions and what they are needed for
Nitrate ions - 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 - needed in all living organisms including plants and animals in the formation of ATP and ADP as well as DNA and RNA
Chloride ions - needed in nerve impulses and many secretory systems
Hydrogen carbonate ions - needed for buffering the blood to prevent it from becoming too acidic
Important cations and what they are needed for
Sodium ions - needed for nerve impulses and many secretory systems
Calcium ions - needed for the formation of calcium pectate for the middle lamella between two cell walls in plants, and for bone formation and muscle contractions in animals
Hydrogen ions - needed in cellular respiration and photosynthesis, and in numerous pumps and systems in organisms as well as pH balance
Magnesium ions - needed for production of chlorophyll in plants
Features of water
-It is a polar solvent (polar molecule) so many ionic substances will dissolve in it
-It is an excellent transport medium so many different substances will dissolve in it
-Ice is less dense than water forming an insulating layer
-Slow to absorb and release heat so has a high specific heat capacity
-Cannot be compressed
-Water molecules are cohesive (stick together)
-Water molecules are adhesive (attracted to different molecules)
-High surface tension
