Weekly Response Sem 2 week 1

1. 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. 2. Explain why the disruption of chemiosmosis and the proton motive force can be detrimental to eukaryotic organisms. Provide a real life example. 3. Compare and contrast obligate and facultative anaerobes. 4. 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

It has been a while since the last blog and we are now trying a new blog where we have questions to answer as well as describe what we did.

This week we did quite a bit of work on cellular respiration as well as some work on photosynthesis. Cellular respiration and photosynthesis are pretty much the reverse of each other, we learned about that in freshman Bio. Respiration takes in oxygen and releases carbon dioxide, while photosynthesis takes in carbon dioxide and releases oxygen. Now of course it isn’t really that simple, that is just the easiest and most condensed way to remember it.

In our cells, we use cellular respiration for the main purpose of energy. Without cellular respiration, we as people would die. We have two types of cellular respiration, Aerobic and Anaerobic. Aerobic requires oxygen while Anaerobic doesn’t. Aerobic respiration is the one that I think of when it comes to cellular respiration, simply because we breathe. Without oxygen, Aerobic respiration could never occur and we would die. The bodies energy comes from cellular respiration, specifically the mitochondria, which break down glucose using oxygen. Glycolysis is the first step of cellular respiration, it occurs outside of the mitochondria in the cytoplasm of the cell. It is caused by the breakdown of glucose, it creates 2 ATP as well as pyruvate and NADH (which are used in the next step). The next step is the Krebs cycle or the citric acid cycle (really just preference) In the Krebs cycle, the 3 carbon molecule is broken down, releasing 2 co2 as the waste. 2 ATP released While this is occurring, electrons are being added to NADH and FADH for the next step. The next and final step is the electron transport chain, which pretty much takes all of the electrons from the original glucose to be used in the body. The electrons are used to pump the protons (hydrogen molecules) into the membrane space and they are added to the oxygen we breathe (aerobic respiration) as well as the other protons to make water (H2O). This step can produce 32 ATP alone. From all of the steps of Aerobic respiration combined, 36 ATP can be created. Now for Anaerobic respiration, this is normally used during exercise such as running or swimming. The problem that we run into with Aerobic respiration is that in glycolysis, the electrons used go to NAD+ turning it into NADH and the problem is that eventually, we run out of NAD+. Anaerobic respiration solves this problem, but all athletes will know the consequence. Pyruvate can change into lactate, which will accept the extra electrons and allow the cycle to continue. The issue with Lactic acid fermentation is that the acid begins to wear on your muscles, it makes you sore and breathe more heavily. This is because the lactic acid needs to be broken down as carbon dioxide and released when you exhale.

2. Chemiosmosis is the movement of ions across a semipermeable membrane, down their electrochemical gradient. Why this is important to us is because in cellular respiration, hydrogen ions need to be able to move across the membrane in order to generate ATP. If there was an issue with this is that if it were to have an issue, the body would stop getting the majority of it’s ATP and die. A real life example could be a disease that doesn’t allow chemiosmosis to occur, and the patient would die unless it was fixed.

3. A facultative anerobe is an organism that makes ATP by aerobic respiration if oxygen is present, and can switch to fermentation or anaerobic respiration if there isn’t oxygen. An obligate anaerobe can’t make ATP in the with oxygen, and die in the presence of oxygen.

4. Oxidation and reduction both have to do with electrons, one is gaining while the other is losing. The Best way to remember this is OIL RIG (Oxidation is losing, Reduction is gaining) In cellular respiration, NAD is being reduced, making it the oxidizing agent. NADH is being oxidized, making it the reducing agent.

Wow that was probably the longest blog that I have ever written and it actually helped me to get a better understanding of Cellular respiration, so although it wasted over an hour of my time, it was beneficial in the long run.


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