Writing in Biology

Titration curves have always confused me. I was introduced to them as a freshman in college. I didn’t really understand the whole concept of conjugate base and an acid and how they related. I didn’t understand what pKa or Ka meant but now I think after taking upper level courses the relationship between pKa, pH, acids, and conjugate bases all finally makes sense. On a titration curve there are inflection points, this point represents the amount of base required to react one half of the desired acid. At this point the acid becomes half deprotonated and half protonated. Next is the equivalence point, the point that represents the amount of base to react with all of the desired acid. This now makes sense to me why the acid is noted as HA and the conjugate base is noted as A-. The acid (HA) is neutral and when it becomes deprotonated taking on its conjugate base form (A-) it loses a proton and now has a net negative charge. This is how I started to understand the relationship between pKa and pH. Again, at the inflection point the amount of conjugate base is equal to the amount of acid. When you plug this ratio into the Henderson-Hasselbalch equation you get pH=pKa+log(1), log(1)=0. So that means that pH=pKa. Which now makes sense why stronger acids have a lower pKa. It essentially means that they are more will to give up a proton at a lower pH.

In my lab, I am researching how reactivation of specific memories during sleep can be modulated using external stimulation. We will be releasing an odor into a subject's nose while they sleep and see if affects their ability to remember and recall certain information. So far we have not found anything significant however, there has not been a lot of work done. We believe that this odor could affect the ability to remember things because there is a lot of evidence that points to the idea that it could. Usually, recent memories are replayed during sleep. Since we will be showing our subjects images right before they go to sleep that they were supposed to memorize, this idea can apply to our study. This study has been performed in animals before. It’s important to note too that it has been observed that matching a sensory stimulus with information and an odor facilitates things such as coordination of sleep spindles.

Proteins have complex structures that determine the many functions proteins will perform in the body, and these structures are a result of the endless combinations of the 20 biological amino acids. There are four levels of protein structure. The primary structure of a protein is simply its amino acid sequence. Covalent peptide bonds between the amino and carboxyl groups of amino acids form, building a polypeptide chain. The secondary structure is the structure of the polypeptide backbone, excluding the R groups of the amino acids. It involves hydrogen bonds that stabilize alpha-helices and beta-sheets formed. The tertiary structure factors in the chemistry of the R groups, finalizing the overall structure of the protein, which can be globular or fibrous in form. R groups can be nonpolar, polar and uncharged, positively charged, or negatively charged. Depending on the proximity of these groups, different structures can result from the non-covalent electrostatic interactions. Finally, the quaternary structure is only relevant to proteins that are composed of multiple polypeptides. It involves the various electrostatic interactions between the different subunits within the overall protein.

Cells receive an array of signals that tell them what to do. Cells receive signals to survive, grow, divide, or differentiate, and if a cell receives no signals, it will undergo apoptosis and die. Cancer cells dont need survival signals, and this is why they continue to survive even when no signals are being received. Signals are typically small molecules or proteins. Hydrophobic signals, such as hormones, will enter the cell across the membrane and attach to receptors in the cell. On the other hand, hydrophilic signals cannot get inside of the cell and will bind to receptors on the cell surface. The same signal can be received by the same receptor, but depending on the cell type, the signal may cause different outcomes in the cell. For example, acetylcholine is a common signal, but when it binds to the same receptor on a different cell, different downstream proteins result. Signals usually set off signal cascades in which the message is amplified. Any time there are enzymes and multiple steps incolced in the transduction cascade, the signal can be amplified. This amplification of signals makes crosstalk more plausible. Crosstalk is when pathways intersect, affecting one another. The more steps in the pathway, the more opportunities for crosstalk. And the only way to completely stop the communication of a signal is to eliminate the last step of the pathway. 

Throughout genetic history, there have been many concepts of heredity, both incorrect and correct. Scientists once believed that genetic information would travel from various parts of the body and then collect in the reproductive organs of the human. Another bizarre concept is the idea that a miniature organism live in sex cells throughout life and that all the traits are inherited from one parent when an offspring is born. Lastly, the idea that genes in the body mix together to form into the genetics material is false. The correct concepts include the germ-plasm theory where all cells have a complete set of genetic material. The cell theory of all cells arising from only cells is also proven to be true concept of heredity.

Infrared waves were discovered in the 1800s by William Herschel and have longer wavelengths than visible light as well as ultraviolet. Infrared is something that is heard of often this is because infrared is often used for a variety of technology that the military uses such as night vision goggles. Infrared energy can be seen using appropriate equipments and it shows the different temperatures of what is around.Advancing in military technology is essential in fighting in wars and coming out victorious which makes infrared important. Infrared can also detect many things in the universe that visible light cannot detect, objects such as stars, nebulas, as well as planets can be seen. The James Webb Space telescope uses infrared energy to reveal objects hidden in the universe. Keeping infrared helps reveal the mysteries of the universe and plays a major role in astronomy. Infrared therapy is also common, the absorption of infrared rays expels the carbon dioxide found in the body and also helps with decreasing inflammation found in the body. Infrared improves the immune system which is helpful for people who get sick often. Infrared rays can help diagnose and treat illnesses. This allows for humans to get treatments for diseases and illnesses without having to undergo surgery.  The radiation that infrared emits is what satellites use to study the changes in land and sea surface temperatures. This is important for others to tell what is going on in earth. It heats up the earth and allows for humans to be able to survive on earth by keeping it at the perfect temperature which allows for humans to live. Infrared data also helps distinguish from a fire and just a hot place, meaning it allows for fires that are not easily detected to be put out. Helping the habitats of animals to not be destroyed. The negative aspect of infrared is radiation which can in turn damage the eyes of a person, taking the appropriate precautions will allow for a person to not have any more severe damaging effects.

Euthanasia is the painless killing of a patient who is suffering usually from a disease, there are two types of euthanasia that are often debated on, active and passive. Active euthanasia involves actually killing a patient, for example this can be done by lethal injection. Passive euthanasia means letting the patient die by not trying to cure the disease or whatever is bringing the patient pain. A patient who is dying of cancer would stop chemotherapy and stop taking the medication required that keeps them alive until they eventually pass away. Often it is argued that active euthanasia is worse than passive euthanasia because active euthanasia means that someone is actually doing the killing. James Rachel however, in “Active and Passive Euthanasia,”  argues that this is not true and that both forms of euthanasia are equal and both are morally the same. Winston Nesbitt takes Rachel’s article and argues against it stating that active euthanasia and the act of actually killing a person if far worse than passive euthanasia.

The effect of Ulva on Gigartina is best described as facilitation. This is because in the presence of Ulva, Gigartina is able to survive and grow. Ulva is making it more suitable for later species with its presence. When Ulva is removed the number of Gigartina recruits is close to 0. Which further backs up the idea that it is Ulva that creates the suitable environment. In figure 3 the control groups shows that the mortality for aspen and fir trees are about the same time with aspen having a slight higher mortality in comparison. When the aspen trees are thinned in early aspen successional stages the mortality for aspen stays around the same. However the firs experience an increase in mortality percentage by more than doubling their mortality. This means that there is a link between having thinner aspen and having less fir.The mechanism controlling these interactions is facilitation. Looking at Figure 1 it can be seen that aspen is the first colonizer after aspen is able to thrive fir then starts taking it’s place almost eliminating the fir. In figure 3 it can be confirmed that fir needs aspen in order to thrive. Thinning out the aspen creates higher mortality in the fir trees. This is facilitation because one of the species benefits with the introduction of another species and without that species fir is unable to grow.

Different proteins need to be in different areas on the cell, and the different areas of the cell are sectioned off as organelles with walls and membranes that block the way. This is why protein trafficking is a very important area of regulation in a cell. Proteins start from genes contained within the DNA of a cell, and this DNA is strictly kept inside of the nucleus. This DNA is transcribed inside of the nucleus into mRNA, which is what is able to leave the nucleus and give rise to proteins that need to circulate to the rest of the cell. This mRNA codes for signal sequences within its transcript that indicate where the coded protein needs to be transported, where it needs to be translated into a protein. These signal sequences can signal for the resulting protein to be imported into the endoplasmic reticulum, to be retained in the endoplasmic reticulum, to be imported into the mitochondria, and so on. The signal sequence is usually an area where a transport protein can bind and move the mRNA to an organelle while being translated. The protein that is translated usually remains unfolded until iside its organelle, except for proteins going to the nucleus. Fully folded proteins are able to go inside of the nucleus through a regulated pore. The signal sequence for nuclear import is called the Nuclear Localization Sequence (NLS). A protein called Importin binds to the NLS and binds to the Nuclear Pore Complex (NPC) of the nuclear membrane. This allows the Importin and protein to enter. Once inside, the protein Ran bound to GTP binds to Importin, causing a change in conformation that releases the protein into the nucleus. This GTP-Ran-Importin complex exits the nucleus. 

    In our society, there exists multiple cultural ideas that stemmed purely from commercial greed. For example, the idea that men must propose using a diamond ring, came about from western commercialism and the need to sell diamonds. Suddenly, diamonds are very expensive because of this tradition, even though most diamonds are actually surprisingly cheap. They’re constantly sold for thousands of times their actual worth; when in reality, even the most fancy diamonds are only worth three to four hundred dollars. The same thing goes for milk. Although it is true that milk contains a lot of calcium and vitamin D, it actually isn’t that healthy to drink. Yet through commercials and advertising, marketing companies were able to put a spin on the idea that milk is actually great for you. The reality is that milk is only good for you if your body is able to readily digest it, and that only goes for a very slight portion of the actual human population. For the most part, everybody is lactose intolerant to a certain degree, east asians especially. It’s incredibly to think that some of these traditions and ideas are not even a hundred years old yet, yet most people do not even think about it, and eventually believe that it’s been a cultural aspect of our society for centuries.