Water and Ph

• Water is an essential substance for plant and animal growth


  True
• Without water, there would be no life on earth

  True
• Water is essential to life and is in solvent water that

  the chemical reactions of biological processes

  evolved.

  True
• Although not an organic biomolecule, water is the

  major component of the cell, making around 70 to

  90% of its weight and inert space filler in living

  organism.

  True
• Due to its highly reactive and unusual properties

  and its ionization products H+ and OH-, water is an

  important factor in modifying structures of

  biomolecules such as nucleic acids, carbohydrates,

  proteins, lipids, enzymes, and other cell

  components

  True
• Chemically pure water is colorless, odorless and

  tasteless.

  True
• Water has a higher boiling point, osmotic pressure and high specific heat.
• Water has high latent heat of vaporization and high surface tension
• Water had the capacity to dissipate heat to its

  environment.
• Water is an excellent solvent for ionic compounds

  because of the attraction between the ionic

  components of the molecules and the water dipoles

  is sufficient to overcome the attraction between the

  ions themselves.
• Non-ionic polar compounds are also very soluble in

  water.
• Their polar functional group [OH] readily

  hydrogen bonds with water molecules, dispersing

  the compounds among the water molecules.
• Other substances dispersed by water are those

  hydrophobic group known as amphipathic

  molecules such as salts and fat acids and are called

  micelles.
• Micelle formation is important for an

  understanding of organized biological

  system among amphipathic compounds

  such as proteins, phospholipids and

  nucleic acids.
• Water is an irregular tetrahedron with oxygen at its

  center.
• Two hydrogen are bonded with oxygen forming

  105o a slightly skewed tetrahedron.
• Because of this structure electrical charge is not

  distributed uniformly about the water molecule.
• The oxygen side is partially negative because of the

  relatively rich in electrons and the two hydrogen

  forming a region of local positive charge.
• The unequal distribution of charges with in a

  molecule is term “dipole” such as in water.
• Colligative properties such as freezing point and

  boiling point, vapor pressure and aromatic pressure

  are altered by dissolved solutes.
• Colligative properties depend only in the

  number of solute molecules per unit

  volume of solvent and independent of their

  chemical structure.
• Dissolved solutes disturbed hydrogen

  bonding in water molecules, thus reducing

  its effect as a solvent.
• Though water ionizes slightly forming hydrogen ion

  and hydroxyl ion
• PHYSIOLOGICAL BUFFER SYSTEM - A system that can resist a change in pH upon the addition of either acid or base is called a buffer.
• Solutions of weak acids and their conjugate bases

  and on weak bases and their conjugate acids

  exhibit buffering.
• Functional groups such as carboxyl group, amino

  group and phosphate esters are functional groups

  of are weak acids or bases that many biomolecules

  possess.
• Inorganic ions - Vital to the normal functioning of some enzymes

  and for the maintenance of functional conformation

  of proteins, nucleic acids, and carbohydrates