/
FN 225: Nutrition
Tamberly Powell, M.S., R.D.
Health Professions Division
Lane Community College
Eugene, Oregon

LECTURE 3A: Chapter 4- part 1
Covalent Bonds
(NOT on Exam 1)


Test this week (Week 3)
I would recommend creating an index card, with anything you choose written on it, to use for the test.  Since it is an exam that you are taking online, and it won't be proctored, you can use your notes.  However, it is a 49 question test and you will only have 90 minutes to take it.  You will not have unlimited time to look for answers in your notes.  Therefore I would suggest creating an index card to use as a study tool. 

Be certain to take and then study the results of the online review quiz in Week 2.  There is also a study guide wiki you can help fill out and view. 

Remember if you don't take the test by Thursday of Week 3 (and have not made previous arrangements) you will have to go to the LCC instructional testing services to make up the test.  You will NOT be able to take it from home.  The instructional testing services does not have an open note policy, but you can use a 3x5 notecard. It is located in the center building where the bookstore use to be, room 311.
 

Supplementary Videos in Moodle:

This week you will have an introduction to atoms, elements, covalent bonding, photosynthesis, and cellular respiration.  These topics can be confusing for students, especially those who do not have a science background.  I will be posting some supplementary videos in moodle to help explain these concepts.  They do go into more depth than your required to know, so when it comes to studying for the exam, stick to your lecture outline.  

 

Forum this Week

Lecture 3B will list the forum questions for this week. As always you can use the forums to ask questions. 

Also, feel free to start your own conversation!  If you have a topic you would like to discuss, post a new discussion topic in the forums.

  



Now For the Lecture...

The first part of lecture 4-1 and the study questions for this week (#1-12) will focus on introducing you to atoms, electrons, bonds, and molecules. I have a few different resources to help explain these abstract concepts below.


The first part of the lecture is a series of slides that was created back in the late nineties by Beth Naylor. "The Path to Inner Peace" will help you fill out both lecture outline 4-1 and the Study Questions (#1-12).  
 

Why is this information important?  Throughout this course we will be looking at the chemical structure of nutrients. The purpose of these resources is to introduce you to chemical structures, and explain what elements, electrons, and covalent bonds are. "The Path to Inner Peace" explains these concepts in a very simple, visually appealing way.



Below are the elements that make up ethyl alcohol. Notice they do not have full outer shells. Therefore, they will go hunting to bond with other elements to complete their outer shell.

Can you see that one of the 6 hydrogen atoms in the picture above has now moved down to combine with a carbon atom? This hydrogen would now have a full outer shell (2 electrons). The carbon still does not have a full outer shell with only 5 electrons. Remember carbon needs 8 electrons in its outer shell to be full and stable.

Now 5 of the 6 hydrogen atoms in this picture have moved down to combine with carbon atoms.

Once all the carbon, hydrogen and oxygen bond...

Inner peace because all the atoms have full outer shells. Hydrogen-2, oxygen- 8 and carbon-8. There is energy in these covalent bonds, and we can utilize this energy when we break these bonds in cells. More to come on that in lecture 3B.
 

 

 

The youtube video below is another resource to introduce you to atoms, electrons, and molecules.  This video will give you slightly more detail and will contain more animation.

 

Here is a link to the above video:  http://youtu.be/eESpP5okA1I

The video mentions fat and carbohydrates being the energy providing nutrients.  From week 1 you also know that protein is an energy-yielding nutrient, but it is not the main role of protein (perhaps that is why it is not mentioned).  In addition to Carbon, Hydrogen, and Oxygen, proteins also contain Nitrogen.

The above video discusses atoms needing 8 electrons to fill their outer shell, like carbon and oxygen.  What is not mentioned is that Hydrogen only has one valence shell, so it only needs 2 electrons to have a full outer shell and be stable.

In the lecture outline you will see the following images.  The first image is representing Hydrogen, which only has 1 valence shell, and only has 1 electron, so it is looking to bond with another atom to complete its outer shell with 2 electrons. 

Oxygen has two shells, the first one already being full, and the second one only having 6 electrons, so oxygen needs 2 more electrons to have a full outer shell of 8.

 

When these atoms come together to make the molecule, water (H2O), as seen below, they both are happy and stable, with hydrogen now having a full outer shell of 2 electrons (through the sharing of electrons, or covalent bonding), and oxygen having a full outer shell with 8.