Writing in Biology

In this lab the number of organic compounds in two unknown analgesics and three known analgesics was measured by thin layer chromatography.  The two unknown analgesics were identified by comparing their elements to the elements in the known analgesics. During the first part of the lab, Aspirin, Acetaminophen, Caffeine, Unknown 1 and Unknown 2 were dotted onto a silica plate using capillaries.  The silica plate was then developed in about 4 mL of ethyl acetate. In order to stop the small samples of analgesics from being washed away it was important to ensure that the ethyl acetate level stayed below the dots. It was also important to keep the silica plate vertical so that the solvent did not move up the silica plate at a diagonal. Once the solvent reached about a centimeter away from the top the plates were dried and observed under UV light and in Iodine crystals.  The distance traveled by the solvent and spots was then measured and the Rfs calculated. The average Rf of Aspirin was found to be .3305, Acetaminophen to be .337, Caffeine to be .347, seemingly corresponding compounds in Unknown 1 to be .085 and .3565, and finally Unknown 2 to be .2625. After reading into research, it was discovered that caffeine should have a much lower Rf than was found. Therefore, the organic compounds that are in Unknown 1 appear to be the same organic compounds found in Caffeine and Aspirin. The organic compounds found in unknown 2 appear to be the same unknown compounds found in Acetaminophen and Aspirin. These results were found by comparing the Rfs of the known compounds to the unknown compounds.   

     For the second part of the lab, the effect of solvent polarity on Rfs was tested.  In order to accomplish this, two identical plates were prepared with Anthracene, Benzil, and Triphenylmethanol.  The difference between the two plates was their development solvent. One was developed in Ethyl acetate (the same solvent used in the first part of the experiment) and the other was developed in 95% hexane and 5% t-butyl methyl ether (a nonpolar solvent).  Since Ethyl Acetate is so polar, the Rfs of all three compounds dotted onto the silicone were close to one. This means that the distance traveled by the compounds was almost as much as the distance traveled by the solvent. This is due to the tendency of the compounds being more drawn to the polar solvent than the less polar silicone plate.  The Rfs of the compounds developed in hexane were much smaller meaning the compounds were more drawn to the polar silicone plate than the nonpolar solvent.

Cells are able to replicate themselves identically so that they can proliferate and increase in number and decrease in size. They do this cyclically, with different stages preceding the division and then the final separation. This is known as the cell cycle. The cycle is composed of the G1, S, G2, and M-phase. These stages are when the cell is going to divide, there is another phase, where the cell is not going to divide. G0 is also known as the cell being in quiescence. The G1 phase stands for gap or growth phase. This is the start where the cell checks for nutrients, energy and DNA damage to make sure it is ready to replicate the genome and then split the cell. It preps for replication by making nucleotides and proteins required for DNA replication. The S phase is the synthesis phase where DNA replication occurs. G2 phase is another gap phase where the cell grows some more, checks that the cell completed DNA replication, and checks the DNA for damage. The M-Phase is where there is chromosome segregation and spindle assembly. This is the phase that houses the steps of mitosis and includes cytokinesis. Cytokinesis occurs at the end of M-phase, after the stages of mitosis are complete, and cleaves the two halves the cell so that they are separated and now two different cells.

Isometric contractions are contractions in which that generate force without altering the length of the muscle. These muscles are common in body parts that are responsible for grips, such as your hands and forearms. These muscles are also prominent in maintaining posture. You experience isometric contractions when you are trying to lift items that are too heavy for you, leading to the object not being lifted. In this case, the maximum force a muscle can generate has been reached. In contrast, isotonic contractions do involve shortening. Force is generated by isotonic contractions by the change of length of muscles. These isotonic contractions can either be eccentric (the muscle lengthens) or concentric (the muscle shortens). With isotonic contractions, you are able to lift the object that you are attempting to lift, unlike isometric contractions. 

As a result of climate change, globally there are rising water levels everywhere and melting ice caps, leading to an increase in these sea levels. In the Mediterranean, a sea level increase of more than 2 feet is expected by the end of the century. However, a sea level increase of 1.7 feet would be enough to flood the beaches of Alexandria and displace 8 million people throughout Alexandria and the surrounding delta. Since 1964, a strong positive increase in sea level can be seen in Figure 1. This graph shows the sea level trends at Alexandria Harbour Station from 1944 to 2006. The area in gray was data collected prior to the building of the dam, so the increase here can likely be attributed to sediment build up and therefore disregarded. The completion of the dam between 1963 and 1964 is indicated by the change in color and this positive relationship is likely attributed to climate change. There is a clear indication of sea levels rising in Alexandria, which have lead to salt water infiltrating soil and irrigation as well as leading to increased flooding.

In our example, the population is increasing. When lambda is 1 the population remains stable. When it is below 1 the population is decreasing, and when lambda is above 1 the population is increasing. The table shows that the population is increasing. Looking at Figure 10.8 B we see that the population size is increasing. From year 1 to year 5 the population increased by 1037.3 individuals. Our lambda increased by .21 from year 2 to year 5. From year 2 to the next year was the biggest increase in lambda. After the first initial jump lambda continued to increase just by smaller increments every year. If we continued the table, we would notice that lambda would eventually reach a constant assuming our survival and fecundity rates remain constant.

At the end of the day, all domestic breeds of dogs are going to die except for one. This one special breed should be the Australian Shepherd not only because of its temperament, beauty, and workaholic mentality, but because it has such a rich tradition and culture that follows it. Native American tribes revered Australian Shepherds for their stunning beauty and pale blue eyes thus spurring legends and tales of the “Ghost Eye” dog. Australian Shepherds are held sacred by many people along with the Native American Tribes. Ever since their introduction in the 1840’s these dogs have been seen in film, rodeos, lore, and legend and thus have deep roots in the lives of many people. To lose such a marvelous breed of dog would directly impact the lives and cultures of people all around the globe. In conclusion, when it comes time to choose that one lucky breed that survives this pandemic, that breed should be none other than the Australian Shepherd.

Amoeba is a single cell organism that likes to live in warm places, they were first discovered in Australia but this brain eating Amoeba is believed to have evolved in the U.S. Only this past month a man in Texas died because of a brain infection called Primary Amebic Meningoencephalitis. According to the Centers for Disease Control and Prevention (CDC), Amoeba is a microorganism that can be found in lakes, ponds, and pools. The infection occurs, when the contaminated water enters the body through the nasal cavity. It is by this route that the parasite reaches the brain and destroys the brain tissue. It is estimated that only a dozen people in the world have survived the infection. Usually, an anti-parasitic drug called Miltefosine is given to treat the patients and in 2013 this medication saved two lives. The only recommendation is to keep the water out of your nose, when swimming in fresh water by covering your nose with your hands. 

Amoeba is a single cell organism that likes to live in warm places, lately this organism has been causing the death of people around the world. This past month a man in the U.S died because of a brain infection called primary amebic meningoencephalitis. How can we avoid this parasite?

According to the CDC, Amoeba is a microorganism that lives in sweet water that can be found in lakes, ponds and pools. The infection occurs, when the contaminated water enters the body through the nasal cavity.

Synthesis of Cyclohexane via Dehydration of Cyclohexanol

Purpose:

The purpose of this lab is to synthesize cyclohexene via an acid-catalyzed dehydration of cyclohexanol with phosphoric acid, in addition to purification of product through fractional distillation and analysis using chemical tests and gas chromatography.

Reaction Scheme:

Experimental Procedure:

The hotplate was turned on upon arrival to around 400℃. Two g of cyclohexanol and .8 mL of 85% phosphoric Acid were placed into a round bottom(rb) flask along with boiling chips.  A fraction distillation apparatus with aluminum foil wrapped around the cylinder containing copper mesh. The mixture was then heated over the aluminum block to fractionally distill at a rate of one drop per second with drops collected in a collection vial.  Once there is a about a 10% of the mixture left in the rb flask, distillation was stopped. After the distillation stopped the contents of the collection vial were moved to a test tube. In the test tube two layer were observed and both layers were mixed using the pipette, then using water to wash. Using the pipette, the lower aqueous layer was removed and placed in waste. Then 1mL of 1M sodium hydroxide was added to the tube and again through washing the liquids were thoroughly mixed and the bottom layer was removed to waste. Then 2 mL of brine were added and the contents of the tube were mixed well via washing and the bottom layer was removed to waste.  

Using a clean pipette, the organic layer was transferred from the test tube to a new clean

collection vial.  Several spheres of CaCl₂ were added in the new collection vial and the contents were gently swirled until the spheres were no longer clumped together, then the vial was left capped and to dry for 5 minutes. The product was then transferred to a preweighed vial using the pipette, leaving the CaCl₂ spheres. Chemical test where then performed on the cyclohexene, then 3 drops of potassium permanganate was added to each tube. After swirling, the cyclohexane remained purple in color, while the cyclohexene formed a pinkish color that turned colorless.  A few drops of the product were left in the vial for the gas chromatography test and IR spectroscopy.