Writing in Biology

Lithium aluminum hydride (LiAlH4) was not used as a reducing agent because it reacts too violently with the benzoin. For this experiment, changing the reducing agent from NaBH4 to LiAlH4 would not have caused an increase in the amount of conserved product. The use of NaBH4 showed that benzoin was completely reduced. Spot (C) on the TLC plates shows that there is a separation between the starting material and the product, therefore the starting material is not the same as the product. A more polar product is shown due to the differences in the Rf values, which confirms that the product is 1,2-diphenylethane-1,2 diol because the mechanism shows that the starting material is less polar than the product. After the benzoin is reduced, the hydrochloric acid protonated the oxygen ion. Adding more hydrochloric acid to the solution could make it so that the oxygen ion is more efficiently pronated, which would yield a higher product yield.

Gram stains are a very basic yet useful technique in determining types of bacterial cells. Gram negative cells have a thin outer membrane that can be easily broken down and dissolved. Gram positive have have the opposite, they have a thick outer coating. Gram stains rely on these two defining traits. The procedure for Gram staining is straightforward. First bacterial cells are placed on a microscope slide. If the cells are being drawn from a liquid solution they can be easily spread on the slide, if the cells are being used from a solid colony water must first be applied to the slide. Once the slide dries it will get heated fixed by passing it through a flame two times. This process ensures that the cells stick to the slide during the stain. The first stain of the bacterial cells is with crystal violet, this will turn the cells a purple color. Once the crystal violet is washed away with water the crystal violet is adhered to the cell after Gram’s iodine is applied. The Gram’s iodine will also be washed away with water. Next, the cells will be treated with ethanol. The ethanol will wash away the outer lining of Gram negative cells but not Gram positive cells. The cells will then be stained with pink safranin. This will turn Gram negative cells pink but will not affect the purple color of Gram positive cells because purple is darker than pink.  

Losses from invasive species arise when there is a decrease in agricultural yield, loss of biodiversity, and an increased spending on herbicides and pesticides used to control the invasive species. Identifying the extent to which agricultural yield, loss of biodiversity, and the amount of labour or money used to control the plants identifies where the threat is coming from. With knowledge on the invader's impact, we will potentially pinpoint the source of greatest loss and manage the problem accordingly. This would potentially protect our food sources, our local environment, as well as reduce our spending on maintaining the environment.

Gram stains are a very basic technique that can be used in the lab to help identify a type of bacterial cell. The process is very easy. First you want to streak a little bit of your sample on to a microscope slide. If the sample is liquid this is fine but if the sample is solid you must first add a drop of water to the slide to make sure that you can spread your sample out on the slide. Once this smear dries you can then heat fix it by passing the slide through a flame very briefly two times. You then apply a few drops of crystal violet to the slide and let them sit there for one minute. After the minute is up wash off the crystal violet with water. Next you repeat this process with Iodine. Next you place a few drops of ethanol on the slide and let them sit for 10 seconds. This washes away any previous stain done. Next you add safranin which is a differential part of the stain. Any gram negative cells will appear as pink, the color of safranin and any gram positive cells will appear as purple because they retained the purple color from the first round of stains.  

Aneuploidy usually alters the phenotype drastically. In most animals and many plants, aneuploidies are lethal. Because aneuploidy affects the number of gene copies, but not their nucleotide sequences, the effects of aneuploidy are most likely due to abnormal gene dosage. Aneuploidy alters the dosage for some, but not all, genes, disrupting the relative concentrations of gene products and often interfering with normal development.  A major exception to the relation between gene number and gene dosage pertains to genes on the mammalian X chromosome. In mammals, X-chromosome inactivation ensures that males (who have a single X chromosome) and females (who have two X chromosomes) receive the same functional dosage for X-linked genes for further discussion of X-chromosome inactivation).

Once pyruvate is formed from glucose it can be used in multiple pathways. Gluconeogenesis is the anabolic synthesis of glucose from pyruvate, but it is not the exact reverse of glycolysis. Pyruvate can also participate in two different catabolic processes: fermentation and slow cellular respiration. Fermentation happens when oxygen is low or energy is needed quickly, and there are two kinds: homolactic fermentation, which occurs in muscle cells, red blood cells, and some bacteria, and alcoholic fermentation, which occurs in yeast and some bacteria. The purpose of this fast anaerobic respiration is to regenerate NAD+ so that glycolysis can continue, and it does not generate additional ATP. Slow cellular respiration occurs when there is enough oxygen and the need for energy is not urgent. In slow respiration, pyruvate is used to synthesize acetyl-CoA to be further oxidized. Acetyl-CoA is an acetyl group attached to coenzyme A and is the central molecule in metabolism of fuel molecules. Formation of acetyl-CoA from pyruvate by a pyruvate dehydrogenase complex is the “point of no return” in carbohydrate metabolism. It cannot be converted back to pyruvate.

Digestion of a cheeseburger starts in the mouth. Saliva contains enzymes, amylase and lipase, that begin to break down the food. Amylase starts to break down carbohydrates, and lipase begins to breakdown fats. The saliva moistens the food and begins to liquify it. The cheeseburger then travels down the esophagus through peristalsis, coordinated movement of food along the digestive tract. Once the cheeseburger enters the stomach, food is broken down by enzymes secreted by cheif and parietal cells and mixed around by segmentation. Cheif cells in the stomach secrete pepsiogen, which once it enters the stomach becomes pepsin. Pepsin breaks larger proteins into smaller pieces. Parietal cells secrete hydrochloric acid which denatures proteins. The cheeseburger them travels into the small intestine where chemical digestion continues until completion. When the cheeseburger enters the large intestine, it hase been completely broken down; the main function of the large intestine is compaction of waste and absorption of water. Once through the large intestine, the nutrients from the cheeseburger have been completely absorbed, and the waste travels to the anus for defecation. 

The metabolism includes both anabolic and catabolic processes. Catabolic processes are exergonic and spontaneous while anabolic processes are endergonic and non-spontaneous; however, metabolic coupling between biochemical pathways allows endergonic reactions to still occur. In metabolic coupling, energy released from an exergonic reaction is used to provide energy needed for an endergonic reaction. This energy is often exchanged through phosphate groups. Molecules with phosphate groups tend to have high free energies, so the removal of a phosphate group by hydrolysis results in a largely negative change is free energy. Phosphorylation, on the other hand, requires energy input. The magnitude of free energy available in the bond is the phosphoryl group transfer potential, and molecules with larger phosphoryl group transfer potentials can phosphorylate molecules with lower potential. In other words, energy released through the hydrolysis of a phosphoryl group is used to power the phosphorylation of another mloecule. An example is the coupling that occurs to power muscle contractions. Creatine phosphate is hydrolyzed to form creatine, and this energy is used to phosphorylate ADP to ATP. ATP is the main energy currency molecule in nearly all cells.

Overall ojective: to identify the diveristy of volunteer plants that grow with the same host species that is grown in two different environments: an individualy potted and group potted. Specific Aim 1. Identify the number of different volunteer species growing with the host plant in an individual and group potted environment. Groups will take pictures and count the number of different volunteer species growing with a host planted in an individual pot in the Morrill Greenhouse and in a group pot in the Durfee Greenhouse. This aim will provide data for analysis in aim 2. Specific Aim 2. Identify the species of volunteer plants growing with the host species in an individual and group potted environment. Groups will use Greenhouse weeds in the Botanical Garden of Pas in Warsaw-Powsi to identify the species of volunteer plants growing with their host species in the individual and group pots (Halin and Halin 1999).