Today is my first big exam of the semester. I’ve studied a lot, but I’m nervous. I have all of the conceptual stuff down, but there are so many scientific microbial names that just don’t want to cement in my head. I have until 5 pm, which is good and bad. I perform better earlier in the day and I want to get it over and done. But I also could use some extra time to review. My plan is to review this afternoon until a couple of hours before the test. I have found it’s not a good thing for me to look at my notes right before an exam because I inevitably find one little detail I didn’t remember and then I start to doubt myself. Maybe I’ll catch up on all of your blogs for the hour or two before my exam. I am very behind!
Since I am in the science mindset after days of studying, I thought it would be a good day to do another entry into my “Lessons Learned” series. Again, for those of you in the field of science you probably already know this, but for the rest of us, I think these little tidbits are fascinating! I love learning about how the body works! This is straight out of biology 101….
Most of us are pretty active (since we read healthy living blogs), and most of us have heard of lactic acid. But what is it reallly? It all boils down to fermentation! Nice thought, huh?! When I think of fermentation, I think of making cheese, beer, wine…. The list is endless! But I never really thought about what that means in my body. What is fermentation, and why does it occur? Well, here are the nuts and bolts…
Cellular respiration and fermentation are two ways that the cells of an organism harvest energy from food. Both processes begin with another process called Glycolysis. Glycolysis occurs in the cytoplasm of the cells in all organisms and does not require oxygen to be present. When the process of Glycolysis is complete, glucose has been converted to 2 molecules of ATP (a quick source of energy), 2 molecules of NADH, and two 3-Carbon molecules called pyruvate.
If oxygen is present at the end of glycolysis, cellular respiration takes place in the mitochondria of the cells, producing a great deal more ATP (energy). However, if oxygen is not present, an anaerobic process occurs in the cytoplasm to metabolize the pyruvate created through glycolysis, and to harvest more ATP (energy). This anerobic process is called fermentation.
There are two types of fermentation. Lactic acid fermentation occurs in some fungi, some bacteria, as well as in the muscle cells of humans. When intense exercise results in a lack of oxygen, for example, cellular respiration is not possible. Consequently, in order for the muscles to continue working, energy must be produced through lactic acid fermentation, in which the pyruvate (produced during glycolysis) is converted into lactic acid and NAD+. This process produces only a small fraction of the ATP that is produced during cellular respiration…but despite its inefficiency, it it is necessary to produce a quick burst of energy when oxygen runs out or is not present at all.
Alcoholic fermentation is the second type of fermentation. In alcohol fermentation, which occurs in some bacteria and in yeast, the pyruvate, produced during glycolysis, is converted into 2 molecules of ATP, as well as ethanol, NAD+, and CO2. We see the CO2 biproduct in the rising of bread!
Interestingly, the products of both types of fermentation are toxic to the organism. In lactic acid fermentation, the lactic acid can change the pH in the blood. Therefore, it is necessary for the body to rid itself of the build up of lactic acid by shuttling it to the liver where it is converted back into pyruvate. The same is true in alcoholic fermentation. The alcohol produced as a waste product can actually kill the yeast itself. Therefore, when the amount of alcohol produced surpasses the level that the yeast can tolerate, the yeast will die and fermentation will halt.
Of course, there is a lot more detail involved in all of this, but I think it is just fascinating to think about how our bodies are programmed to keep us going even under stress. When we are working out hard and there is not enough oxygen, our body knows it needs to get energy in another way. We pay with a bit of muscle soreness, but our body also knows how to fluch away the lactic acid. Hopefully, we are smart enough to know when we have reached are limit and need to slow down to increase our oxygen intake. Our cells prefer to perform cellular respiration because it produces more energy, but in a pinch, our body know just what to do!
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Hopefully I haven’t put you all back to sleep. That may be a little to much if you haven’t had your morning coffee yet! So I will leave you with my dinner from last night, which should be less taxing than learning about fermentation!
I love leftovers and last night I got to finish up my eggplant lasagna. It was just as good the second time and I paired it with a monster salad. Spinach, broccoli slaw, blueberries, egg white, tomato, red pepper, artichoke, cucumber…. If it was in my fridge, it was in this salad!
Just a reminder that my first giveaway ends on Friday! You don’thave to be gluten-free to enjoy these treats. They’re delicious!
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