My AP Biology Thoughts  Unit 1 Episode #33

Welcome to My AP Biology Thoughts podcast, my name is Alex and I am your host for episode 33 called Polarity of Water and Hydrogen Bonding. Today we will be discussing the importance of water polarity and hydrogen bonding in biology.

Segment 1: Introduction to Hydrogen Bonds

What is water polarity and what are hydrogen bonds? Water is polar because of its asymmetrical structure and uneven distribution of electrons. The structure of water is asymmetrical because of electron pairs within the oxygen, causing the O-H bonds to be pushed down towards each other. The uneven distribution of electrons is caused by the oxygen having a higher electronegativity, pulling in the bonded electrons more strongly than the hydrogen. This causes a partial negative charge on the oxygen side, and a partial positive charge on the hydrogen side. Hydrogen bonds happen when a positively charged hydrogen of one molecule has a polar covalent bond with a Nitrogen, Oxygen, Fluorine, or Chlorine of another molecule.

Segment 2: Example of Water Properties

An example of these properties are the cohesive property of water. This is caused by the hydrogen bonding in the water, creating an attractive force between the molecules, this allows water molecules to clump together, which gives water its surface tension and adhesion to other molecules. 

Another example of water’s polarity is its high heat of evaporation. The relatively strong hydrogen bonds are able to strongly hold the water molecules together. This makes it take a lot of energy to break the bonds between water molecules, and evaporate the liquid. This is an important property of water as it allows water to present on most of Earth no matter the current temperature or climate.

Segment 3: Making Connections

The polarity of water and hydrogen bonding is an essential part of biology. These two properties are responsible for so many properties of water, which are extremely essential for life to exist. Ice floats because of the hydrogen bonds in water, but if ice sank then many aqueous ecosystems would die in the winter as the ice would freeze the entire lake instead of the surface. Water’s polarity also gives it a very high specific heat capacity, which allows organisms to effectively regulate their body heat through releasing water from their systems. The polar structure of water is essential for all living organisms, especially because many organisms are primarily composed of water. Water’s polarity leads to many more properties, such as being a universal solvent, as well as the universal base and acid, all of which are essential properties to all living things.

 

Thank you for listening to this episode of My AP Biology Thoughts. For more student-ran podcasts and digital content, make sure that you visit www.hvspn.com. See you next time!

Music Credits:

• "Ice Flow" Kevin MacLeod (incompetech.com)
• Licensed under Creative Commons: By Attribution 4.0 License
• http://creativecommons.org/licenses/by/4.0/

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