Writing in Biology

The aim of this experiment was to observe biofilms microscopically by growing them on a slide using a process called slide culture. Using a technique called flow through Gram stain, the biofilms on the slides were kept wet to maintain their complex arrangement. Keeping biofilms wet is essential to preserving their structure, and allows them to be seen under a microscope. The inoculum for these slide cultures was obtained from two different sources. The first slide culture sample was taken from a pure culture of Pseudomonas aeruginosa. This Gram negative, rod shaped bacteria is an excellent at forming biofilms, which contribute to its virulence in humans and animals. It was expected that P. aeruginosa would produce a thick, slimy, dense biofilm on the slide culture. It was also expected that extracellular polymer substance (EPS) would be able to be seen under the microscope.

After the extraction, the product yield was 0.622 g which was a 59.35% yield from the mass of the nutmeg that used. The extraction is the first step to isolating the trimyristin from nutmeg and the product from the extraction was recrystallized to purify it. The percent yield after the first recrystallization was 25.08%. The melting point for this product was between 54 and 56 °C. The literature gives a melting point range of 56-57 °C for trimyristin. The range matches closely and the crude product upper limit is the same as the given lower limit for trimyristin. The first recrystallization product can therefore be confirmed to be trimyristin and the slightly lower level in melting point suggests it is not yet a pure sample. After the recrystallization, a melting point between 55-56 °C is achieved for the product. Some of the material was used for the hydrolysis, but what was used to recrystallize gave a 72.91% yield. The melting point range decreased by 1 °C and moved closer to the literature range for trimyristin. As the second recrystallization was of the crude trimyristin product of the first recrystallization, not changes should have occurred, and the product can be identified as trimyristin. The 0.062 g taken from the first recrystallized product was used in the hydrolysis and acid addition part of the experiment and gave a product that after drying weighed 0.049 g which gave a 79.03% yield in product. The dried sample also had the melting point taken and was recorded at 54 °C. The literature gives a melting point value of 54.4 °C for myristic acid, so the product of hydrolysis and acid addition can be identified as such.

SIGNIFICANCE  

    The findings of this study will be very beneficial for multiple reasons.  The data we collect will give us insight into the behavior and lives of the small cellar spiders that live in basements and homes right alongside humans.  Not much is known about the effects of LEDS on spiders and specifically on creating a web in the presence of LEDs. Today and going forward, LED lights are the new light bulb, they are more efficient, cheaper, easier to install and use, etc.. This means that the LED light will began to have a much larger presence in the outdoors as street lamps, lights in the park, etc..  With LEDs becoming more and more prominent and mixed into our surroundings, this study will show some of the effects LED lights can have on spiders creating their webs, eating, sleeping, and just their overall behavior. This study, in part with others, can then be used to decide where to put LEDs up, how intense to have them, and the schedule for the LEDs. This study could also bring insight into the most effective ways to repel spiders from living and coming into houses and other places.

Biome 2 doesn’t have a direct match to an earth biome however it does follow a similar seasonal pattern to a tropical rainforest. Rainforests have little seasonal variation and therefore have pretty consistent precipitation and temperature patterns throughout the year. Because the data on biome 2 shows little seasonal variation it can be expected that this biome is located near the equator. The closer to the equator you get, the less of an effect the axis has on climate, so there is little variation. I would predict this biome to be equatorial because of the lack of seasonal variation. I would not consider it to be a tropical rainforest however because it has much less average precipitation and a much lower average temperature. The lack of precipitation would not allow for the abundance of species found in a rainforest. You might expect to see similar plants, as in ones that are not acclimated to seasonal change. They would not lose their leaves in the winter. You would expect to see a lot of vegetation year round because their is still substantial rainfall and there is never a period of freezing temperatures that would prevent the growth of many plants.

Biome 1 is most similar to a temperate deciduous forest based on both temperature and precipitation. Temperate deciduous forests vary seasonally in terms of both temperature and precipitation. The winters are typically cold and dry and the summers are warmer and typically see more rainfall. The peak of both precipitation and temperature occurs some point in time over the summer. The graph for biome 1 shows seasonal variation, with the winters having below freezing temperatures and the summers ranging in temperatures between 20-30 degrees celsius.  The biome on this new planet has slightly warmer summers than this earth biome but follows a similar pattern. This biome also has more rainfall on average than earth but again, has a similar seasonal pattern. You would expect this biome to be located around 30-50 degrees latitude. On earth, this type of biome is found mostly in the northern hemisphere because the southern hemisphere lacks the landmass needed, however, since we don’t know of any land differences between the northern and southern hemisphere of this planet, it can be expected in both hemispheres. You would also expect to find plants with deciduous leaves, so they loose their leaves in the sub freezing winters. Because there is such variety seasonally, the plants would likely be well adapted to seasonal change. On earth, you find maple, birch and many other types of trees so you might find similar trees in this new biome. There is more rainfall as well so it might be expected to contain larger trees.

To determine the relationship between spider weight and spider web thickness, 3 different species of spiders of different sizes will be collected from various sites around campus. We will collect 2 spiders in each species. The spiders will be weighed on analytical scales and will be sorted based on weight. They will then be placed in separate containers  and will be allowed to spin out spider silk.The spiders will be left in their containers to make a web for 5 days. We will feed them 1 fruit fly each day. We will remove the web with tweezers and place onto a microscope slide. The silk will be fixed onto microscope slides using distilled water as a buffer. The silk will be observed under a microscope at 40x magnification and be characterized based on size, using a stage micrometer, and web type. The webs will be sorted based on type, and then subgroups will be made based on size. The data will be analyzed based on the spider species and then the web size will be compared to spider weight to determine if any correlation exists.

Results:

Figure 1:

TLC plates no pictures, actual plates

Table 1:

Table 2 TLC analysis for the plates:

TLC Plate 1:

TLC Plate 2:

Discussion:

In this experiment, benzoin was reduced with sodium borohydride and recrystallized to 1,2-diphenylethane-1,2-diol(0.239 g) with a recovery of 39.05 %.  The product, (1,2-diphenylethane-1,2-diol), was determined through TLC analysis and melting point. The TLC analysis showed the presence of two different compounds (seen in Figure 1).  The starting material (spot A) traveled the same distance on both the TLC plates with Rf values of .77-.79 which are very close. This is different than the recrystallized product and the crude product (spot B) in plates 1 and 2, respectively.  The recrystallized product and the crude product travel a shorter distance and therefore have a lower Rf value that are very similar to each other, .54 and .57 respectively. The co spots (spots C) show that there are two compounds presence since both contain two spots with two different Rf values.  

This means that a starting material other than the starting material has formed in both the crude and the recrystallized product.  Additionally spot B on both plates contain only one spot and neither matches the starting material spot so therefore Benzoin (starting material) must not be present in the crude and recrystallized product.  

The TLC plate is a silica gel plate that is polar, which means polar compounds interact more with the plate and don’t travel as far as relatively less polar compounds.  Benzoin was expected to travel further than 1,2-diphenylethane-1,2-diol because it is less polar. This was supported by the TLC plate and observations made. The melting point also supported that the recrystallized product (1,2-diphenylethane-1,2-diol) was relatively pure as it’s MP range was 135-137 ℃, which is two degrees, signifying purity.  The melting points for this lab is very important because it tells us how pure the substance is and in some cases is able to determine the isotope of a certain compound.

To improve purity a different substance other than HCl could be used to cause a slower reaction, which in turn would increase the purity of the product.  Yield could be increased by raising the temperature slightly when mixing in this lab as it takes a long time for the solids to dissolve which could mean some is being left out or not completely dissolved.  The warming would allow for all the starting material and materials involved to be used to their fullest.

Post Lab question:

This would mean that there would be 3 different compounds in the mixture.  

The spot with the same Rf as the starting material is the starting material, and the other two spots with different Rf values are most likely the expected product, the secondary alcohol.  The difference between the last two non starting material spots could be because they are different isomers of the same compound.

            When creating a poster, it is important to keep in mind that you must visually attract someone to it and draw them in. As seen from the examples, this can be done with bright colors, pictures, and diagrams. From the posters I looked at, most of them were laid out in such a way that my eyes were able to flow from one section to the other without being bogged down by too many words and too much information. Positioning of data is important while constructing a poster. If the data is too cluttered, the reader might get overwhelmed and lose interest in what is being presented. While having enough data on the poster is crucial, leaving some negative space is just as important so that the eye is not constantly bombarded with information and can relax between sections. I also observed the limited amount of lines per section. The authors of several posters seemed to limit themselves to just a few lines of text so that it seemed easy to read and comprehend. These factors are important to keep in mind as they would prove beneficial when constructing a poster of my own.

            Conversely, I noticed some details on the example posters that should not be replicated. For example, several posters were very drab and unappealing. They were only designed in black and white and lacked any sort of visual aid. Bogging down the poster with only text and data tables can make the poster a little intimidating to those who don’t quite understand what you are talking about. It also gives the appearance that the information on the poster will be difficult to grasp as you’d have to constantly bounce between tables and text so you can grasp the information being presented. I also noticed that some posters write in paragraphs rather than short two to three sentence blurbs. To be honest, I didn’t even read the paragraphs while looking at the poster because I thought it would take up too much time. Paragraphs can be daunting to an outside reader due to the high concentration of information and the amount of time it takes to read through it all. Lastly, I noticed that several posters had their titles the same size and font as the text in the body of the poster. Without the title being any different than the rest of the poster, there is no visual context as to what is being presented. Instead, it is easy to glaze over the title and move on to something else that come across as more appealing and interesting based on the title alone. Such factors like the ones discussed above should be avoided as they would not contribute to the presentation of a well-laid out poster.

Conversely, I noticed some details on the example posters that should not be replicated. For example, several posters were very drab and unappealing. They were only designed in black and white and lacked any sort of visual aid. Bogging down the poster with only text and data tables can make the poster a little intimidating to those who don’t quite understand what you are talking about. It also gives the appearance that the information on the poster will be difficult to grasp as you’d have to constantly bounce between tables and text in order to grasp the present information. I also noticed that some posters write in paragraphs rather than short two to three sentence blurbs. To be honest, I didn’t even read the paragraphs while looking at the poster because I thought it would take up too much time. Paragraphs can be daunting to an outside reader due to the high concentration of information and the amount of time it takes to read through it all. Lastly, I noticed that several posters had their titles the same size and font as the text in the body of the poster. Without the title being any different than the rest of the poster, there is no visual context as to what is being presented. Instead, it is easy to glaze over the title and move on to something else that come across as more appealing and interesting based on the title alone. Such factors like the ones discussed above should be avoided as they would not contribute to the presentation of a well-laid out poster.

When creating a poster, it is important to keep in mind that you must visually attract someone to it and draw them in. As seen from the examples, this can be done with bright colors, pictures, and diagrams. From the posters I looked at, most of them were laid out in such a way that my eyes were able to flow from one section to the other without being bogged down by too many words and too much information. Positioning of data is important while constructing a poster. If the data is too cluttered, the reader might get overwhelmed and lose interest in what is being presented. While having enough data on the poster is crucial, leaving some negative space is just as important so that the eye is not constantly bombarded with information and can relax between sections. I also observed the limited amount of lines per section. The authors of several posters seemed to limit themselves to just a few lines of text so that it seemed easy to read and comprehend. These factors are important to keep in mind as they would prove beneficial when constructing a poster of my own.