Writing in Biology

In the 19^th century, there was debate about the brain and how it functions. There were two different theories of how the brain worked. Camilo Golgi, best known for creating the Golgi stain, had theorized that the brain was circulatory network such as the heart and that neurons were all connected. Another scientist Santiago Ramon y Cajal believed that the brain worked via contact rather than connection. He theorized that neurites of different neurons are not continuous with each other and communicate by contact. The theory that was proposed by Ramon y Cajal would be known as the Neuron Doctrine. However, his theory was not accepted until proven much later by the electron microscope, and is now universally accepted. 

This is where the two paths diverge. With the discovery of nuclear fission both countries started nuclear programs, but the amount of resources dedicated to them varied greatly. In the US, the program started slowly. At the start of the program the idea of a nuclear weapon was a distant thought. In a letter written to Winston Churchill by Bohr in 1944, he recalls that a few years prior the idea of a complete and functioning bomb was a “fantastic dream” (Bohr Letter). Allied British scientists thought that the bomb wouldn’t be a weapon of this war, but one for the future due to the vast amount of resources needed to produce it. The American’s estimated the costs of the project to be much lower than they actually were when the project was complete. This misplaced optimism may have played a part in their decision to put what is now equivalent to $30 billion dollars into the creation of these weapons. This project was never guaranteed to pay off, and putting this enormous of an effort into something during wartime is a big risk. The German nuclear project was run differently. Instead of focusing only on a nuclear weapon, the Germans set out to harness all facets of nuclear power, including nuclear energy. This meant that the already limited resources of a country at war were to be spread even thinner, making the bomb even less of a priority for Germany (Walker 24-25).

Autopolyploidy causes the offspring to be reproductively isolated from its parent species. After the formation of the tetraploid offspring the gametes that they would form would be 2n of 6 chromosomes. The parent species forms gametes with n of 3 chromosomes. The parent species and offspring species can produce an offspring with 3n, although they would be sterile because gametes would not be able to form since a chromosome would be left unmatched during meiosis. This is an example of post-zygotic reproductive isolation because the offspring would be sterile but would have been viable. 

Using Bloom’s taxonomy from Lesson 1, I believe that on the pyramid this question would be apply. I believe this because you are taking information we have been given and applying it to the question. In this problem you have been given beforehand which amino acids have been in each category, although, in this problem we are not asked to determine the amino acid shown in the picture, but to determine the category of the picture and then pick one of the listed that is also in the correct category.  In order to answer the question correctly, demonstrate your knowledge of the classifications of amino acids.                                              

Defensin genes in snakes are expressed in the pancreas and are used to fight infections, in humans, pigs and mice they are also used to fight infections. Gene is the process of generating new genetic material by copying the gene sequence. Regulatory mutations are presences of enhancer or silencers in a region of DNA that can control transcription. Coding sequence mutations are changes in the DNA sequence which leads to different proteins being synthesized. These three mechanisms helped evolve defensin genes into venomous crotamine. Gene duplication helped evolve crotamine by creating copied of defensin genes to attack different pathogens. A regulatory mutation which changed where a protein was produced was duplicated in snakes, the new protein location allowed snakes to release the defensing into the bite wounds of the prey. More mutations of the duplicated gene caused for the evolving of the defensin from attacking pathogens to attacking the prey’s muscles. Different venoms evolved from different genes from either the heart or brain. These genes went through regulatory mutations that were duplicated over and over. More mutations fine-tuned them into the venoms today.  Venom genes were seen to be in a common ancestor of all snakes. 

Metamorphosis, Greek for transformation or change in shape, describes what takes place once a caterpillar forms a chrysalis.  There are four stages to a complete metamorphosis in insects; the first being the egg, larva, pupa, and finally adult form.  When a female monarch butterfly lays her eggs she chooses a healthy leaf to do so, as the leaf then becomes food for the delevoping larva.  Monarchs, in particular, choose the milkweed plant on which to to lay their eggs, as the toxic sap from the plant translates into the caterpillars’ bodies, making them toxic as well.  The toxicity keeps predators away as the caterpillars continue to eat until body size has increased one hundred fold.  During this growth process the caterpillars also molt about four to five times to make room for more growth.  After 9 to 14 days from hatching, a caterpillar will be about 2" long and fully-grown.  The goal for a caterpillar at this stage is to be sufficiently nourished for the later formation of a chrysalis.  

In understanding the importance of the discovery of the structure of the ribosome, it is imperative to understand the groundbreaking experiments that led up to it. Prior to Avery, Macleod and McCarty’s experiment showing DNA as the transforming principle, it was widely assumed that proteins carried the hereditary information that encoded life. This was due to the fundamental understand of protein and DNA at the time. Chargaff had discovered that the composition of DNA varied from species to species, however containing only four alternating bases, DNA was seen as too simple to carry the complex information that encodes all of the information across life. Proteins on the other hand, were known as incredibly complex and variable in an infinite way. The Avery-Macleod-McCarty experiment, later repeated and verified by Hershey and Chase as well as X-ray crystallography experiments performed by Rosalind Franklin provided the clues needed for Watson and Crick to hypothesize about the structure of DNA, which was only later proven by Meselson and Stahl, who’s experiment showed the semi-conservative replication of DNA that provided a model for the successful replication and thus hereditability of DNA. In the early 1960’s, Nirenberg and Matthei were the first to crack the genetic code, using synthetic poly-uracil RNA, which showed that RNA controlled the production of specific types of proteins. Roughly 50 years later, the detailed mapping of the structure of the ribosome provided the last link to the puzzle.

Providing the structure of the large and small subunit of the ribosome allowed for the development of a whole new class and specificity of drug targeting. The ribosome has been a target for antibiotics, however bacteria have become increasingly resistant to these developed antibiotics. The specific mapping of the ribosome can now be used to develop new antibiotics targeting different and new mechanisms in the ribosome, previously not known.

Overall, this laboratory exercise demonstrated the major elements that effect imaging in fluorescence microscopy. The net local concentration and degree of overlap of fluorophores and amount of the fluorescent dying in certain areas greatly effects the ability to achieve a bright and clear fluorescent microscopic image. Additionally, important microscope parameters such as the neutral density filters, and shutter/exposure time of the sample can greatly affect the brightness of an image and the rate at which fluorescent light decays over time, which is important to control in order to uphold the integrity of a sample.  

I traveled to the Durfee Conservtory located behind the Morrill buildings to find a plant to photograph. After walking through the first room of plants from the front of the greenhouse and into the second room, I circled the room to assess for the plant that stood out to me the most. On the far left against the wall, I found a flowering plant with two different flower color-combinations. One was white and pink, and the other was a light orange and pink. The plant was in a pot sitting on some pebbles with a plant of either side. It had big, sturdy green leaves and thick stems with white covering. I took several photographs of the flower, both up close and at a distance. The tag sticking in the soil read, "Cattleya 'War Paint'". I then left and created a figure with Inkscape.