Chemistry in Living Things

• molecule: a substance composed of 2 or more non-metal atoms that are covalently bonded together
• organic molecule: a carbon-containing molecule in which carbon atoms are nearly always bonded to each other and to hydrogen
• intramolecular: occurring between atoms within a molecule
• intermolecular: occurring between atoms of different molecules
• hydrogen bond: a weak association between an atom with partial negative charge and a hydrogen atom with partial positive charge 
• hydrophobic: referring to non-polar molecules that do not have attractive interactions with water molecules
• hydrophilic: referring to polar molecules that have attractive interactions with water molecules
• ion: an atom or group of atoms that has gained or lost one or more electrons, giving it a positive or negative charge
• functional group: an atom or group of atoms attached to a molecule that gives the molecule particular chemical and physical properties
• There are 6 main chemical foundation for the diversity of life: carbon, nitrogen, oxygen, hydrogen, phosphorus and sulfur
• Element: a pure substance with specific properties
• Atom: the smallest particles of elements that still retain the element’s properties.
• A polar covalent bond is stronger than an ionic bond
• Hydrophobic effect is the natural clumping together of non-polar molecules in water.
• • Cancerous tissues in the body are characterized by a much higher level of activity than healthy tissues so that cancerous cells take in more glucose than healthy cells. Doctors can inject radioactive glucose into a patient and trace its movement to diagnose a cancerous tumor which breaks down the injected glucose at a faster rate than normal cells do. 
• Intramolecular force is much stronger than intermolecular one.
• hydroxyl group

  
• carbonyl group

  
• carboxyl group

  
• amino group

  
• phosphate group

  
• sulfhydryl group

  
• hydrogen bond is weaker than ionic or covalent bond
• Hydrogen bonds between molecules in cells help maintain the proper structure and function of the molecule.
• Water is a universal solvent (easily dissolves ions, gasses like oxygen and carbon dioxide, small molecules).
• Expansion on Freezing: Water freezes from the top down, only pure substance that expands when it becomes a solid so it floats when it freezes. It allows life to exist in cold temperatures, so that living aquatic organisms can survive. 
• Water has a high specific heat capacity, resists temp changes. Our cells do not freeze in the cold. It remains liquid over a wide temperature range and changes temperature gradually when heated and cooled. 
• Water is a polar molecule (a great ability to stick to itself and to stick to other things). It allows for the formation of hydrogen bonds, which allow ions and other polar molecules to dissolve in water.
• Water is important for helping to transport substances into and out of cells. 
• High surface tension: water molecule holding together so tightly that the insects is able to walk on that surface without breaking through
• High heat of vaporization: it takes a lot of heat to evaporate just a little water