Cellular Respiration 2

Compare and contrast Anaerobic cellular respiration and Aerobic cellular respiration. In your answer, address glycolysis, the citric acid cycle, oxidative phosphorylation, lactic acid fermentation, alcohol fermentation, NADH, FADH2 and ATP.  At the most basic level, the difference between Anaerobic and Aerobic respiration is that Aerobic respiration uses O2 and Anaerobic doesn’t. Aerobic also produces much more ATP than Anaerobic does (28-38 vs. 6ish). Both types of respiration include glycolysis in the cytosol and produce 2ATP and NADH. Only aerobic respiration has the citric acid cycle (produces 2 ATP and FADH2) and oxidative phosphorylation (produces 26-28 ATP) both of which occur in the mitochondria. Lactic acid and alcohol fermentation are both used in anaerobic respiration. In lactic acid fermentation, pyruvate reduced by NADH, forms lactate. No  CO2 is released (2 ATP produced). With alcohol fermentation, pyruvate is reduced to ethanol in 2 steps; 1. CO2 released from pyruvate and 2. acetaldehyde reduced to ethanol.


Explain why the disruption of chemiosmosis and the proton motive force can be detrimental to eukaryotic organisms. Provide a real life example. When is chemiosmosis (energy coupling mechanism that uses energy stored in the form of a H+ gradient across a membrane)  and the proton motive force (the gradient of hydrogen ions) are disrupted a eukaryotic organism can not produce ATP and you would see mass cell death and ultimately the death of the organism because no energy is being produced. A real life example is cyanide poisoning. Cyanide damaged the mitochondria and prohibited the production of APT and killed people.


Compare and contrast obligate and facultative anaerobes. Obligate anaerobes and facultative anaerobes carry out fermentation. But only obligate anaerobes carry out anaerobic respiration, but cannot survive in the presence of O2. On the other hand, facultative anaerobes can carry out cellular respiration.

In the following redox reaction, identify which molecules have been oxidized and reduced. Also identify the reducing agents and the oxidizing agents.

C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy

Carbon is oxidized due to the conversion from C6 → 6CO2 (looses electrons) this makes carbon the reducing agent.

Oxygen is reduced by taking electrons from the less electronegative Carbon (O6 → 6CO2), making oxygen the oxidizing agent.


Free Energy

From a young age we are taught that nothing in this word is free. This week Mr. Dunn told us otherwise. This week we learned about free energy and its purpose. What free energy is exactly is still a little fuzzy in my brain. The three main things we get from free energy are organization, growth, and reproduction. All energy comes from the sun (or environment). Without this available free energy from the sun our lives would probably not exist today. We utilize this free energy through metabolism (sum of all the chemical reactions in our body). Glycolysis is a series of reactions that happens in our bodies and its cool because we can jump into it at any point in the process depending on the nutrients or energy we are given (its the breakdown of glucose into pyruvate). How energy get to us from the sun is because plants take it in and create sugars and oxygen through photosynthesis. The energy is pasted on through consumption; we eat plants or other things eat plats and then we eat them. Excess free energy goes into storage. Disruptions in free energy can lead to death in an individual and can change a population or ecosystem. To maintain life we need order which requires a constant supply of energy. We also learned about the two laws of thermodynamics. The first one states that energy can never be created or destroyed just changed. The second law is that every time we convert energy, there is more entropy in the universe, or more disorder. This only applies to a closed system. When we create more order, it makes the universe more DISordered. This works because it is an open system not a closed system. This week connected to Big Idea 2.a. Big Idea 2.a talk about free energy and how every living thing needs it and utilizes it to live.

The lab that went along with this week confused me. We made little yeast balls and then put them in hydrogen peroxide and timed how long it took them to go from the bottom of the beaker to the top. Then we tested the yeast balls in different temps. of hydrogen peroxide. We went to 55˚ C and 10˚ C. When it was hotter it went faster and when it was colder it went slower. Full discloser I’m not completely sure why we did this lab or what it taught us. I don’t know how it connected to free energy or metabolism. If someone can explain, please do.

I don’t know how to get rid of this:

All in all I found this week to be a 7 on the toughness scale (1-10, 1 being the easiest). Maybe something that made the week hard was that I don’t quite understand what free energy mean. I sorta understood the idea but I don’t feel strong enough on the unit to take the test. This has been a very hard and confusing unit for me. I don’t understand a lot of chemical reactions or bonds and things like that. It’s hard for me to understand when I can’t physically see it. That’s what made this week so hard. I can’t visualize whats happening in glycolysis and within the body. I also don’t fully understand what’s happening when the universe is becoming disordered. I understand that order in our body is the cells becoming more defined and things like that and evolution is ordered but then what is disorder? We don’t un-evolve. That’s my main questions from the week. The main take away from the week, however, is that yeast balls are super cute.