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

Page history last edited by KimberleyHausheer 13 years, 2 months ago

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


9/3/10- The class started with the texting poll which had first been introduced on Wednesday during lab but seeing it used in class was really cool. It is a great way to wake everyone up and get us thinking. The lecture opened up at first by talking about cancer cells. How cancer is caused by cell reproduction gone south. Then we talked about radioactive isotopes and how their nucleus decays, giving off particles and energy. Glycolysis needs a lot of energy because the cells divide so fast and frequently. Therefore there are higher amounts of radioactive isotopes in cancerous area. PET scans then can detect where the radioactive isotopes are and shows what cells are "hungrier" than the rest.

      Then we discussed atoms which was mostly a review but definitely necessary for me because I forget things very easily. There are three main parts to an atom; protons, electrons and neutrons. Protons are positively charged. They provide the character of the atom. The amount of protons determines what element it is. Electrons are the tiniest part. They orbit around the nucleus of the atom extremely fast. So fast that you can not pinpoint at any time where an electron might be.They are negatively charged.  The orbital is the most likely position where an electron would be at any given point in time. They provide molecular shape. Neutrons have no charge and are a part of the nucleus. They contribute to the atom's mass.

     We also discussed shells briefly. The first shell fits two electrons and then the ones following that fit eight. The amount of electron in the valence shell, or outermost shell of an atom determines it reactivity with other atoms.

     Finally we discussed bonds which ties in with an atom's reactivity and valence shells. There are three types of bonds hydrogen, covalent and ionic. Hydrogen bonds are weak. Covalent bonds are the strongest in physiological conditions. Covalent bonds are when electrons are shared. However often they are not shared equally due to the number of protons and the electron density this is called a polar covalent bond. Nonpolar is when the electrons are equally shared. Ionic bonds are between ions which are charged atoms, caused by an unequal number of protons and electrons. In ionic bonds the electron is taken away.


9/8/10 The class started with the question "why does ice float on water?" The answer being because water is denser than ice. This puzzled me at first and still tricks me sometimes if I don't think about it because I think of ice as being hard therefore it is dense. But that is incorrect thinking. We finished discussing bonds by reviewing hydrogen bonds.  In water the molecules are constantly bumping into each other and creating and breaking hydrogen bonds. In ice on the other hand, there is less energy and the molecules do not break there bonds as much and are more separated. I think of them as creating diamond shapes. Hydrogen bonds are the weakest bonds, however, when there are a lot of them together like in ice and DNA they can be strong. They are also what holds water molecules together. The main topic of the lecture was the special properties of water. Two of the main properties were that is the number one solvent and that it is usually in a liquid state. We went into a little detail of why water is such a good solvent and molarity of a solution. We also went into depth about how it is so difficult for water to change from a liquid to either a gas or a solid and how that property is an advantage. At the end of class we briefly went over concentration and how to find the pH. I was a bit confused with the equation to find the pH and how it tied in with everything.


B.  Useful Materials

1) New Look For Chemical Bonds (submitted 9/12/10)-  Single double and triple elements are well known to moset elements. In the 1960s chemists discovered that you can create a quadruple bond.This is an article found at physiscworld.com that explains that they discovered that uranium can form molecules with five covalent bonds.


2) YouTube plugin error

This video first goes over ionic bonds and then covalent bonds. It shows that in an ionic bond between sodium and chlorine, chlorine takes sodium electron from its valence shell. This causes the sodium to become a positively charged sodium ion. The chlorine becomes a negatively charged chloride ion. Covalent bonding occurs when neither atom has sufficient strength to completely remove the other atoms electrons. It shows a covalent bond between oxygen and hydrogen.


3) This website talks about bonds and goes over a lot of the same information the book does but in simpler terms. If you didn't quite understand covalent bonds or you just want to review them then you should check out the link. I have not explored the entire website but there are a lot of other pages of information on other specific topics we are learning about. IN the column on the left there is a blurb titles Very Cool! If you follow the GO THERE! button it brings you to more information and animations of bonds. 



Comments (3)

Derek Weber said

at 2:24 am on Sep 9, 2010

9/3: No update.

Derek Weber said

at 2:05 am on Sep 11, 2010

9/8: Updated. Please see my podcast on pH for the answer to your last question. Thanks for posting.

Derek Weber said

at 4:22 am on Sep 16, 2010

9/15: Two comments -
1. The spacing of your description of the video is a bit off. Please fix.
2. The journal article you cited is just a summary. The actual article is : (L Gagliardi and B Roos 2005 Nature 433 848). Please try to find the article or at least an abstract and link to it directly. It is fine to show a summary article like Scientific American but I also want you to locate the article itself.

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