Properties and functions of water
Properties and functions of water
I mean, water. What more is there to say? It’s water for crying out loud. It does cool tricks.
Take for example alphabet soup.
In the beginning, it’s just a dry a$$ powder, overly salty, overly hard, overly dry, totally inedible and all-round disappointing. But add a bit of hot water and BAM! you have yourself a totally delicious, mind-blowingly satisfying dish.
Same with life. It can’t just be earth. It needs water. It needs a solvent, a containment environment for its chemicals. Many of life’s basic reactions like condensation and hydrolysis rely on water being present.
Water is to solvent as bear is to North Pole . It is polar. Water is a polar solvent. I could have just said it plainly but I had to insert a ludicrous arctic animal joke. So, water is polar. Because the oxygen in water has a negative charge relative to the hydrogens which bear a relative positive charge, ions such as those found in sodium chloride (NaCl) can bind respectively to the oxygen side or to the hydrogen side. Thus, the salt is soluble and dissolves.
The dipole nature of water enables hydrogen bonding which takes place between the hydrogen atoms of one water molecule and the oxygen atom of another.
As such, it is no wonder that water is the main component of cellular cytoplasm. It is present both inside and outside of cells and fulfils the role of transport medium in plants and animals. This includes the cell sap in plants which enables turgor pressure to prevent cells from collapsing onto themselves, and animal fluids such as plasma, serum, tissue fluid, lymph and urine.
Solutes in water include sugars and proteins, as well as electrolytes such as hydrogen ions (H+), potassium ions (K+), sodium ions (Na+), chloride ions (Cl–), hydrogencarbonate ions (HCO3–), magnesium ions (Mg2+) and others.
The exact composition of different fluids varies between individuals, over time, between species, etc. In order to investigate fluid composition, various methods exist. Sugars and proteins can be detected and measured in body fluids as well as plant extracts using reagent test strips and biosensors.
For example, glucose test strips can measure the glucose concentration in a small blood sample.
Basic legacy tests for the presence of reducing sugars and proteins are the Benedict test and Biuret test. These involve adding a reagent to a test sample and observing a simple….