Zoology - Cellular Respiration

Zoology - Cellular Respiration

Cellular Respiration is generally one topic that students identify as the most challenging. This is because it is a lengthy process. People who tend to fair better at memorizing often struggle with the process, and there are a lot of new terms. So, people who are better with concepts and processes tend to struggle a lot with recalling every detail. This is a topic that really requires a lot of effort to study the terms and to understand the processes. There are 3 main stages to Cellular Respiration: Glycolysis, Kreb's / Citric Acid Cycle, and the Electron Transport Chain. On the WIU Science Teaching Center website, under Zoology 200, there are links for overview type resources that contain more than one stage of the process, and below that, there is a list of resources separated out by stage.  


 
Illustration below: The 3 stages of cellular respiration: Glycolysis, Citric Acid Cycle, and Electron Transport Chain. Photo courtesy of Creative Commons Attribution ShareAlike 3.0.

Helpful Hints for This Blog

Here are a few helpful hints for using this blog (I will update this, adding more to it as I think of more helpful hints).

1. I try to be specific in blog titles, including the subject to which the blog contents best relates. 
2. Over time, as I collect more resources, they will be added to the blog.
1. Resources unrelated to prior posts will be pout into a new blog post.
2. Resources that pertain to prior posts will be added by updating the prior post rather than making a new entry on the same information. This will help reduce space and keep things better organized.
3. At the top of every blog post, you will notices that there is an application for "translate." This application allows you to select your preferred language if it is other than American English.
4. These blogs often appear in a narro strip down the center of the viewing page. To view the blog contents in a more magnified viewing frame on a PC, pus the "Ctrl" key in the lower left of your keyboard and then press the "+" key (next to "Backspace") as many times as needed until the page is comfortable large for viewing.
5. Throughout the blog posts, you will come across a burnt orange / deep reddish colored and bolded words or phrases.  (like what you see here, this links to google)
1. When you bring your cursor over them, you will notice an underline will be displayed under the phrase. 
2. This means that these link out to something else. 
3. These links will open in a new page.
4. If the word or phrase links out to youtube videos or other sites, there will be a description of the site or video.
5. If there is no real description of the word, it is an important vocabulary word that is linked to a site that will further elaborate on the meaning of the word, like an interactive glossary. 
6. On the right hand side of the blog, you will see a "blog archive" where you can view blogs in chronological order by when they were posted to this blog.
7. Also to the right side of the blog, you can utilize the "search this blog" application, which conducts a search for topics, words, etc that might be contained within posts to the blog you have currently open. 
1. To search more blogs, click on the year under blog archive. This will display all blogs posted within that year on your viewing screen and will apply the search to those blogs. 
8. This blog is supplemental to the WIU Science Teaching Center (5-14). This is a site containing a collection of resources for science students and teachers from grades 5-14 assembled by faculty and pre-service science teachers at Western Illinois University.   
1. Please check this site out for resources even beyond what have been collected here.

Biochemistry - Oxidation and Reduction

Oxidation and Reduction are two often very confused processes in science. Both of these processes involve a molecule that can gain or lose electrons.

One common biological molecule that undergoes these two processes is Nicotinamide adenine dinucleotide, more commonly known as NAD+ / NADH. This molecule is especially important in Cellular Respiration.

Before trying to understand the processes, understanding why they can be confused is important. The word reduction typically makes us think "less." Thus, by looking at the chemical formulas NAD+ and NADH, which one seems to have less? - NAD+! In these reactions, however, we are not looking at the number of molecules, but the charge. 

Think about the parts of an atom. 
 Photo 1:
 

• Neutrons are neutral with no net charge
• A proton has a single positive charge
• An electron has a single negative charge

A neutrally charged molecule then, would have the same number of protons and electrons - the positives and negatives cancel out, like the equations below where each number represents a charge, p is protons, and e is electrons. For the sake of this lesson, I am not including neutrons in the equation, due to them having no charge.

1. -2e + 2p = 0
2. 5p - 5e = 0
3. 10p - 10e = 0

However, especially in biological molecules, ions often exist. Basically, an ion is an atom with a charge. In redox reactions (reduction + oxidation), that charge is typically (but not always) a positive charge on the oxidized molecule.   

Compare the atom in Photo 2 below with the atom in the Photo 1 above. What is the same? What has changed?
Photo 2:



In Photo 1, there are:

• 3 Protons (red) = 3 positive charges
• 3 Neutrons (yellow) = no charge
• 3 Electrons (black) = 3 negative charges

Therefore, the molecule in Photo 1 has no net charge because 3 - 3 = 0.

 In Photo 2, there are:

• 3 Protons (red) = 3 positive charges
• 3 Neutrons (yellow) = no charge
• 2 Electrons (black) = 2 negative charges

Now, there is a difference in math. For photo 2, the equation is actually 3 - 2 which means there is a + 1 charge on that molecule. Therefore, this molecule is an ion, just like the NAD+ molecule!
  So then, what is actually being reduced in the reduction portion of the redox reaction? Answer: the charge.

In our example, NAD+ (a +1 positive molecule) is reduced to NADH (a neutral molecule). How is that, though? - Through the addition of an electron. That is reduction.

Oxidation, then, is the opposite. To be oxidized, a molecule loses electrons, usually becoming positive. 

Using what you learned: In the animation below, you can see that one molecule is being reduced, while the other is being oxidized. Notice, here, unlike the previous example, both molecules start off with neutral charges. After the reaction occurs, the sodium molecule (Na) becomes positive and the fluoride (F) atom becomes negative.  The blue dots represent the electrons currently associated with the sodium molecule and the red dots represent the electrons currently associated with the fluoride molecule. Notice, a blue coded electron moves from the sodium molecule to the fluoride molecule.

So, which molecule is being reduced?
(animation courtesy of wikipedia, NaF.gif)

Below are the equations for these reactions. Redox Reaction equation courtesy of wikipedia, Redox Halves

 


Answer to the using what you have learned question: Think about which molecule has a charge that is being reduced. To reduce the charge, an electron (a negative charge) has to be added. Look at the equation above. In the animation, the fluoride atom gains an electron, which takes it from a neutral charge to a - 1 charge. Therefore, it is the fluoride that is being reduced. Oppositely, the sodium ion loses and electron (or a negative charge), becoming a + 1 charge. Thus, the sodium molecule is oxidized. 


 

Introduction

Introduction

Hello science enthusiasts! My name is Stephanie Stenger. I am a teaching candidate for Western Illinois University currently studying for my master's in biology and my education certification in 6-12 science. As part of my master's project, I am in the process of collecting and developing resources for teachers and students to use to better understand especially challenging topics in the Life Sciences. 

Currently, the focus of my resource gathering is in animal sciences (zoology), with my target population being Zoology 200 students at WIU. Despite this being the target population, nearly all of the resources will be made available for a robust set of individuals. Essentially, the purpose of my master's project is promote interest in learning Life Science and providing students with the tools and supplemental resources that may be necessary for success during their science studies. 

This blog is designed so that I can post a lot more "data" heavy information like images and video. The primary database for the resource collection I work on for Zoology 200 can be found at the WIU Science Teaching Center (Grades 5-14) web page under Zoology 200 WIU.  You may find that, over time - as the site becomes more developed - other topics on the
WIU Science Teaching Center (Grades 5-14) site will be very useful as well. 

With this blog and the resource collection, I hope to put together a large collection of resources that are available and accessible to students, teachers, and learners with a wide variety of needs. If there are any resources that you are particularly interested in or any modifications that you might require, please email me at my gmail account (smstenger), and I will try my best to address your needs. 

For every topic I gather resources for, I will try to ensure that there are audio, visual, and text components. Additionally, my goal is to include a variety of approaches to introducing the information with varying levels of difficulty for each topic. 

Please note, this is in infancy, but will continue to grow over the coming months. Additionally, not all resources will be included in these blogs, but all of the resources in these blogs and the other resources collected WILL be included on the WIU Science Teaching Center (Grades 5-14) web page.

Finally, for WIU Zoology 200 students, I also offer tutoring, if 1-on-1 and small group studying works for you. Please refer to your professor and the western online web page for the course for my hours and location.  

Always remember, as Albert Einstein said: "The important thing is not to stop questioning, not to stop research!" My wish is that this project helps you find the answers you seek to your life science questions.

Happy Learning,

Stephanie M. Stenger