Writing in Biology

The three phases of digestion are cephalic, gastric, and intestinal. During the cephalic phase, food has not entered the body, but the smell of food stimulates the central nervous system to start preparing for the injestion of food. The salivatory glands begin to salivate and stomach enzymes are secreted. During the gastric phase, food begins to enter the stomach. A strech in the stomach triggers hormonal and neural signals. Mechanical and chemical digestion begin to take place in the stomach. An increase in pH stimulates G cells to release gastrin, which stimulates stomach and small intesting. The intestinal phase begins when food passes through the pyloric sphincter and into the small intestine. The intestinal phase is regulated by mechanical, endocrine, and neural control factors. 

    Beauty products are used by many people as a way to maintain self care such as make up, masks and face washes. Many of the beauty products have a darker side to them. Parabens is a chemical compound that is used in beauty products as preservatives. It was found that parabens cause and increase in estrogen. A study was conducted where 143 women were tested with a urine test. Even with a small exposure to parabens had an effect on hormone levels. The effect on the body is a gradual effect due to the long time for the chemical compounds to take an effect on the body.

A negative effect of the chemical compounds is the higher risk of developing breast cancer. The gradual increase in estrogen levels has a negative effect on the body. Yet there is not enough research being done to fully understand the nature of the situation.

          Acetic acid (0.774 mL, 13 mmol) and 3-methyl-1-butanol (1.2 mL, 11 mmol) were placed into a 5 mL round-bottomed (rb) flask.  The odor of each compound was noted. Four drops of concentrated sulfuric acid were added to the rb flask and the contents were mixed thoroughly. Boiling chips were added and the flask was placed within a reflux apparatus above the hot plate. The contents of the rb flask were heated to a gentle boil such that vapors condensed about one third of the way up the reflux condenser. This resulted in two phases of liquid collecting in the side arm, which were an upper organic phase and a lower water phase. After the reaction refluxed for fifteen minutes, the apparatus was removed from the heat and tipped back so that most of the upper phase in the side arm went back into the reaction flask, and then lowered back into the hot plate. This process was repeated twice more, so that the mixture refluxed for forty-five minutes total. At the end of the third and final reflux period, the apparatus was cooled completely for fifteen minutes. Once cooled, the entire contents of the side-arm were emptied into the rb flask.

Fatty acids are central molecules in lipid metabolism. They carry most of the energy in a triacylglycerol and oxidation of them releases energy. The oxidation of a fatty acid is a five-part process that starts in the cytoplasm and ends in the mitochondria: (1) acyl-CoA formation, (2) acyl-CoA transport, (3) beta-oxidation, (4) citric acid cycle, and (5) oxidative phosphorylation. While the last citric acid cycle and oxidative phosphorylation steps are the same as in slow respiration, the other three steps are unique to fatty acid oxidation. Acyl-CoA is formed in the cytoplasm by acyl-CoA synthesis, which requires two ATP. The acyl-CoA is then transported into the mitochondrial matrix for oxidation. This transportation is carried out by the carnitine acyltransferase, and once inside, the acyl-CoA cannot be transported out. Beta-oxidation involved sequential cycles of four reactions where electrons are transferred to FAD and NAD+ and carbons are removed as acetyl-CoA, a two-carbon molecule. These four reactions continue to cycle until the whole fatty acid chain is oxidized, two carbons at a time. One thing to note is that the oxidation of unsaturated fatty acids requires additional enzymes and varies based on the position of the double bonds. Fatty acids with double bonds are less reduced than saturated fatty acids and therefore yield fewer ATP per carbon.

If I had a friend that seems to have depression symptoms I could recommend trying behavior therapy. Behavior therapy works to increase the number of positive reinforcers in a person's life. This therapy often goes in hand with the behavior theory which is the idea that life stressors decrease positive reinforcers in someone's life. For example, I could suggest that my friend gets out of the house and hangs out with her friends. This may be a positive reinforcement and may help her "get out of bed in the morning." Although, in the grand scheme of things this may not seem like a permanent or extremely helpful solution, as a friend it is something that I would feel comfortable suggesting.

Trypanosomiasis, human African sleeping sickness generally occurs in 36 sub-Saharan African countries. This disease is a vector-borne parasitic disease and is caused by an infection with protozoan parasites and transmitted to humans by the tsetse fly. This disease not only causes severe disruption in sleep patterns, but changes in behavior, confusion and without treatment the disease can ultimately lead to death. Health officials have reported about 1447 cases of African trypanosomiasis, but many believe that the true number of cases is believed to be much higher that what is reported. Treatments of the human African trypanosomiasis include drugs named eflornithine and nifurtimox, both treatments involve a complicated set of procedures including fusions and pills that are administered in a hospital. Many of the countries where most of the cases occur; put these treatments out of reach for many patients because of its complexity. The new drug, fexindazole, is a much simpler treatment in which it can be taken as a once-a-day pill for 10 days without having to be hospitalized. After the DNDi (Drugs for Neglected Diseases Initiative), a nonprofit organization, teamed up with drug maker Sanofi, they could test the drug on patients and apply for an EMA recommendation for the drug itself. The EMA has just recently approved of the drug and have expressed a “positive opinion” for the fexindazole, opening opportunities for patients to receive treatment earlier and help slow the spread of the disease as well. 

Golden rice is a genetically modified form of rice containing large amounts of orange plant pigment, betacarotene. Betacarotene is an essential pigment that is converted into Vitamin A. Vitamin A is not only important for both our vision and immune system, but vitamin A is essential in keeping many of our organs working properly. This vitamin acts as an antioxidant fighting off cell damage to keep many of our systems working. Golden rice is an example of a GMO food as it has been genetically modified to contain this pigment in order to assist countries with high vitamin A deficiency diseases. Countries with high vitamin A deficiency  include; India, Vietnam, Bangladesh, and the Philippines. Although many people have a negative outlook on the use of GMOs on food, researchers have been able to create this rice to help those individuals with intake of this vitamin. 

The reason why the liver must process the material is because triacylglycerol’s hydrophobic nature makes it difficult to transport and store in the body. Animals attempt to solubilize these molecules through the biosynthesis and distribution of lipoproteins. Lipoproteins come in different types that vary in the percent and type of lipids and proteins that compose it. Lipoproteins have a phospholipid membrane with cholesterol and proteins embedded in it, and inside, they carry cholesterol esters and/or triacylglycerols. Triacylglycerols are then stored in adipose cells, or adipocytes, which are the location of fat storage in animals. Triacylglycerol synthesis is known as lipogenesis and is the creation of triacylglycerol from glycerol and three fatty acids. It occurs in the liver and adipose cells. On the other hand, triacylglycerol degradation is known as lipolysis and is the breakdown of triacylglycerol to glycerol and three fatty acids. It occurs only in adipose cells and involves three enzymes in the process. The fatty acid products then exit the cells and bind to albumin in the blood.

Magnetic fields feel forces when a charge is present. When the charges are moving, the magnetic field exerts a force. The direction of the magnetic force is determined by the direction which the charge is moving and will always be perpendicular to the plane formed by v and B, and is proportional to q, v, and B. Magnetic fields consist of both magnitude and direction like vectors. This can be seen by the right-hand rule when a wire carrying a current is the model. If we rap our hands around the wire, the curled fingers show the direction of the field while the thumb shows the direction of the current. The magnitude then measured by probes.