Chapter 2 Blog: The Chemical Basis of Life I (Siddarth)


In the first section of this page, you will write a daily summary of that day's class.  For example in  your chapter 2 blog, your first entry should be titled 9/3/10.  You should then write a one or two paragraph summary of that day's lecture, outlining the major points.  In the second section, you are required to add two items (link to a website, video, animation, student-created slide show, student-created PowerPoint presentation) and one journal article pertaining to a topic in this chapter.  A one-paragraph summary must accompany each item describing the main idea and how it applies to the lecture topic.  Please see the PBWorks help guide for assistance embedding video and other items directly in the page.  I will also produce a how-to video on using tables to wrap text around items and other useful tips.  Please see the syllabus for organization and grading details.

 

A.  Daily Blog

September 8, 2010: In today's lecture we discussed about Hydrogen Bonds and how they are involved in connecting water molecules. Hydrogen Bonds are known to be very weak bonds. Hydrogen bonds can be broken easily if you are dealing with a few of them. When you try to break up Hydrogen Bonds in huge quantities, they stand strong together and are not easily broken as a single Hydrogen bond. We also discussed the "Special Properties of Water". One property that I probably will not be able to forget are the Hydrogen Bonds that it contains. These bonds help water maintain its liquid form over a wide range of temperatures. Another property of water is Surface Tension. This is caused by a cohesive force that is found on some bugs that help them walk across water. Cohesion is also found in stems of plants. This helps them keep stiff and bring up the water against the force of gravity.

     Another special property is the Absorption of Heat. Water has the ability to take in heat without evaporating immediately. This is found helpful in areas near large bodies of water. During hot days, the water helps take in the heat and create a comfortable living area. During the nights, the heat that is trapped inside the water is released. One of the most important properties of water is its ability to be a solvent for many chemical reactions. Chemical reactions require a aqueous environment and water happens to be one of the most used solvent in nature as well as our own body. We also briefly talked about cation's and anion's. Cation's are positively charged ions and anion's are negatively charged ions. Then we talked about hydrophobic and hydrophilic molecules. An example of hydrophilic molecules is sugar. Sugar has OH- ions which create an attraction the slightly positively charged hydrogen ions part of the water molecules. Triglycerides are hydrophobic  because they have a neutral charge. The reason for this is because the hydrogen atoms are part of a covalent bond and equally share the electrons. Therefore making them a hydrophobic molecule. Towards the end of class, we briefly talked about hydrolysis (the addition of a water molecule to break up a covalent bond) and also mentioned the pH of certain substances. I have to say that when I first saw the equation for getting the pH, I was confused. Then I went home and decided to try it out on my calculator and it worked out fine! Calculator's can really help sometimes : ) 

 

B.  Useful Materials

 

 

 Useful Material
Article 

 

Hydrogen-Bonded Synthetic Mimics of Protein Secondary Structure as Disruptors of Protein-Protein Interactions: 

http://www.ncbi.nlm.nih.gov/pubmed/20827522

This is article is what I found on PubMed. It is a very short article, but just shows the theory of how Hydrogen-Bonds can be strong at one point. In this article, it talks about proteins and their interactions that involve Hydrogen Bond. In our lecture we discussed how Hydrogen Bonds are weak, however they stand strong when they are in numerous amounts. We stated an example was DNA. Another example would be the secondary structure of proteins, where Hydrogen Bonds are being formed constantly in order to strengthen and maintain the structure. 
Link/Video YouTube plugin error   The following video is a very basic tutorial video describing ionic bonds, covalent bonds and metallic bonds. I understand that we have not gone over metallic bonds yet, but this video gives a very straight-forward idea of how ionic and covalent bonds are formed. I have found difficulty understanding the "balancing of the valence shell" and how "atoms share electrons" which form bonds in past years. However, this video shows you step by step what happens to different atoms when they meet and happen to bond. 
Link/Video YouTube plugin error This is a video on the basic properties of water. There is no audio explanation, however it does go through the properties that we have gone over in class. It goes over everything from the basic property of hydrogen bonds connecting individual water molecules to the cohesion of water. Towards the end of the video, there is a simple experiment done to test how electrolytes can conduct water where as non-electrolytes are not able to.