Writing in Biology

The activity of regulatory enzymes is controlled by internal signals that reflect the conditions in a particular cell. Internal signals include substrate availability, cofactor availability, activators/inhibitors, and feedback inhibition. On the other hand, the activity of regulatory enzymes are also controlled by external signals that provide information about conditions in the organism. External signals include activators/inhibitors and hormones, which usually mediate the phosphorylation or dephosphorylation of pathway components. Hormones are chemical signals produced in response to specific conditions and distributed throughout an organism via the bloodstream. They are the primary method of regulation used to control metabolic reactions. Hormones interact with target cell receptors in order to alter the behavior of the cell. Only cells with receptors for a hormone response, and receptor proteins are specific, interacting with one or a few hormones. The same hormone can cause different responses in different cells, even if it interacts with the same receptor. Hormones binding to cell membrane receptor proteins function via a amplification mechanism.

When marine mammals dive into deep, high pressurized waters, they experience an increase in dissolved nitrogen gas in their bloodstreams. The dissolved gas poses a threat because if the divers ascend too fast, they experience a phenomenon known as the “bends,” whereby gas bubbles form inside the body and increase the risk of contracting decompression sickness. Fortunately, marine mammals have a special lung architecture that creates two different pulmonary regions to combat high-pressure depths. They have a compressible chest that limits the amount of nitrogen gas that can be absorbed. The authors of the review article suggest that the physiology of diving mammals is poorly understood, and that there are other cardiorespiratory mechanisms that provide a better explanation for their ability to dive deeply. The results of the paper showed that many marine mammals can withstand high levels of nitrogen gas that would normally cause decompression sickness 50% of the time. The authors also hypothesized that parasympathetic stimulation helps limit lung perfusion, which is a necessary for diving to great depths. They propose that high amounts of stress can interfere with this process and might explain the failure of a normal dive response. Overall, these findings are significant because they offer a new perspective on the physiological and respiratory adaptations that enable cetaceans to dive at great depths. 

When marine mammals dive into deep, high pressured waters, they experience an increase in dissolved nitrogen gas in their bloodstreams. The dissolved gas poses a threat because if divers ascend too fast, it can lead to a phenomenon known as the “bends,” whereby gas bubbles form inside the body and can potentially cause decompression sickness. Fortunately, marine mammals have special lung architecture that creates two different pulmonary regions to combat high-pressure depths. They have a compressible chest that limits the amount of nitrogen gas that can be absorbed. The authors of the review article suggest that the physiology of diving mammals is poorly understand, and that there are more cardiorespiratory mechanisms that provide a better explanation for their ability to dive deeply. The results of the paper showed that many marine mammals can withstand levels of nitrogen gas that would normally cause decompression sickness 50% of the time. The authors also hypothesized that parasympathetic stimulation helps limit lung perfusion, which is a necessary for diving to great depths. They propose that stress can interfere with this process which might explain failure of a normal dive response. Overall, these findings are significant because they offer a new perspective on the physiological and respiratory adaptations that enable cetaceans to dive at great depths. 

I am doing a project for my outbreak class and I chose to look at tuberculosis or more commonly known as TB. What I didn’t know is that TB is a top 10 global cause of death and it has been for quite some time. TB is also becoming more of an issue, not because more people are getting it, it is because TB is becoming resistant to the majority of the drug that treat it. This has become a huge problem around the globe. One example that I looked into was the spread of drug resistant TB in Russia. It has become a huge problem because of Russian prisons. People are kept in poor conditions and in close quarters. Then when people contract TB they aren’t treated properly or given drugs for the full amount of time. This allows the TB to build resistance to the common and most available drugs to treat it with. Now the TB once it is has become resistant to drugs takes a lot longer to treat and a lot more of a strict regimen of taking drugs. This is not followed frequently in prisons due to lack of higher level drugs and lack of coordination from within the prison system.

There are various reports that mentions the response of stomatal conductance to CO2 levels but not many for mesophyll conductance. Since there are limited understanding for mesophyll conductance, Mizokami has been studying this subject from different prospective. From his past case study, he has found that mesophyll conductance is independent from stomatal conductance however, this did not support the influence of ABA and intercellular CO2 levels on the mesophyll conductances (Mizokami et al., 2017). Therefore, to answer the question whether or not decrease in the intercellular CO2 concentration decreases the mesophyll conductance, the first experiment was done (Mizokami et al., 2017). It was examined by comparing the mesophyll conductance responding to instant increase in the intercellular CO2.  Three pots of A. thaliana plant, the wildtype Col-0, mutant ost1, and mutant slac1-2 were placed into a chamber that has an ambient CO2 of 390μmol  . After the plant adjusts to this condition, then the ambient CO2  was switched to 780μmol . The measurements for mesophyll conductance was taken every thirty minutes for two hours and plotted on a graph (Mizokami et al., 2017).

Acyl-CoA is formed in the cytoplasm by acyl-CoA synthetase. Once acyl-CoA has been formed and transported into the mitochondria by carnitine acyltransferase it cannot be transported out of the matrix. Acyl-CoA is then used to carry out the next step of fatty acid oxidation which is beta oxidation. Beta oxidation consists of sequential cycles of four reactions in which electrons are transferred to FAD and NAD+. These four reactions are catalyzed by various different enzymes as carbons are removed as acetyl-CoA. Unsaturated even chain fatty acids are those that require additional enzymes to oxdize as they contain double bonds. These unsaturated even chains vary based on the postion of double bonds and have a small decrease in energy yield for each of the double bonds. There is a reduction in energy yield because fatty acids with double bonds are less reduced or more oxidized than saturated fatty acids therefore yield fewer ATP per carbon molecule. The end result of beta oxidation is the formation of acetyl-CoA. Acetyl-CoA is then used in the citric acid cycle. 

In this lab, isopentyl alcohol and acetic acid were reacted using the process of esterification to produce an ester, isopentyl acetate. The starting materials were reacted using conditions specific to the reaction being performed and some of the target product was obtained in 25.6% yield. The method in which this reaction took place was esterification, where water was removed to force the reaction to move toward its products, an ester and water. The products were analyzed by observing the odor and infrared spectroscopy (IR). The odor of the product appeared to be banana-like, closely resembling the smell of the candy banana Runtsⓡ. This smell is indicative of an ester, specifically isopentyl acetate.

Fatty acids are central molecules in lipid metabolism and are the structures that contain most of the energy in a tracylglycerol. The oxidation of these molecules more energy than a molecule of glucose. This is because the C-H bonds that make up fatty acids are highly reduced while in the glucose molecule most of the carbons are bonded to oxygen. These C-O bonds are already oxidized meaning that these bonds dont have energy to be released. Fatty acid oxidation consists of five processes that generally start in the cytoplasm and are carried out in the mitochondria. The first step is acyl-CoA formation. Acyl-CoA formation is a susbtrate of beta oxidation(which is the third step) and is formed in the cytoplasm by acyl-CoA synthetase. This process requires two ATP(adenosine triphosphate). Once acyl-CoA has been formed it can then be transported into the mitochondrial matrix for oxidation. This transport is carried out by carnitine acyltransferase. 

     You see it everywhere. An actor that had to struggle for two years on ramen and slept in their car. The medical student who had to work so hard, staying up every night until 4AM learning just to make sure they can pass their courses and fulfill their dream of becoming a neurosurgeon. The high school students who play 4 different sports, play in 2 different bands, and keep their studies up by getting inadequate sleep everyday until the end of high school. These people are glorified for their unhealthy lifestyles, because they’re sacrificing their life in order to pursue something they really want. It makes sense, but the glorification can be overdone to the point where people with bad study habits, still think they’re doing great because they follow this example yet still perform poorly. This can be seen a lot of the times, when the problem isn’t that they’re so swamped with work they’re forced to study until the early hours of the morning, but instead they develop bad study habits and yet they reward themselves for having these habits. They think “I tried really hard”, when the reality is they didn’t, but just managed their time poorly.

    The way a student looks at the material of a course compared to the teacher is very different. The way a teacher teaches the material, is that the teacher will teach the fundamentals and the scaffolding that’s required in order to understand the material at a deeper level. That makes sense, and that method of teaching shows that if it is understood by the students, the students will remember and understand the material better. Albeit, while some students see the material under this light, and desire to understand how the material works, there are students who view the problems and see them as “obstacles” that need to be overcome, by any means possible. This means these kinds of students see problems, and instead of thinking about “why it works”,  they think “how can I solve it the easiest way possible”? For some material this method of thinking is more beneficial if a student knows the material they are learning is not a measure of their capabilities of actually understanding the material, but rather a measure of their intrinsic motivation to learn the material for an A. This method of “dodging” the content but still passing the course with an A is a flaw of the current education system, due to the fact that the system weighs two individuals who understand and retain the material at different levels, as equals.