Drafts

Gnathostomes are a group of organisms which have true jaw structures, rather than a simple mouth. It is believed that these jaw structures developed from modified gill arches in fish. The first arch, the premandibular arch, is thought to have moved upward, forming the beginnings of the braincase as a plate underneath the brain itself. The second gill arch, the Mandibular arch, bends forward into two seperate sections. The top, which would eventually form the upper jaw, is called palatoquadrate cartilage. The bottom, forming the lower jaw, is mandibular cartilage. Eventually these cartilaginous structures would ossify in some organisms, giving them boney jaws. The third gill arch, the hyoid arch, forms a structure which supports the jaws themselves, providing a foundation to rest or directly connecting to the jaws. This also serves the purpose of anchoring the jaw to the braincase. Of course this anchoring method differs, or is entirely absent depending on the form of jaw suspension that develops in a particular organism.

A radioimmunoassay is a technique used to detect levels of different substances, usually antigens or hormones in the blood, by using antibodies and forming an antibody-antigen/hormone complex. For example. a radioimmunoassay could measure insulin levels of a particular patient. An antibody-insulin complex would be created (they will bind to each other), but the insulin used will be radioactive labeled insulin. A bunch of these antibody-insulin complexes would be created on a slide, and then the sample of the patients serum will be added in with the slide. If insulin is present in the serum, it will replace some of the radioactively labeled insulin in the previously formed antibody-insulin complexes on the slide. If it is high, it will replace more of them, so there will be more antibodies attached to non-radioactive insulin, and more free radioactive insulin that has been displaced. The antigen-insulin complexes will be precipitated out by the use of a second antibody that attaches to the complex. Then, the radioactivity of the supernatant, which contains all of the free insulin, will be measured. The level of radioactivity quantifies the amount of radioactive insulin that was displaced, which quantifies the level of insulin in the patient.

The purpose of this project is to generate a multipanel scientific figure of a local spider web. In order to do so, three pictures were taken; one of the web, one of the surrounding environment, and one of its location on a detailed map. These pictures were taken with a great deal of thought as later on, a peer will be tasked with replicating the figure based on my methods. When selecting a web to photograph, it was important to choose an area that my peers would have regular access too so that they would be able to replicate the figure as best as possible. For example, the spider webs in my basement werent photographed because not everyne would have access to my basement. The figure presented was set up in order to provide a smooth flow between photographs so that it would be easy for the reader to visualize the location, size, and environment which you can find said spider web. A lot of thought and detail was put into the project so that it would be relatively easy to replicate the figure.

    The two photographs were taken on the front-right side of the Student Union building at the University of Massachusetts Amherst at approximately 3 PM. A bike rack with an overhang was in the close proximity. Between the building and bike rack, an air filtration unit could be seen. On the right side of that was a small metal box with the words “Elect IN rm. 208” written on it in marker. The web was located under that box, and it extended to the right.

The web was large and relatively flat, so I decided to only focus on the right most potion. To take the photo, the camera was held about eight inches above it and pointed directly downwards. A quarter, held between the pointer finger and middle finger of my left hand, was held at the level of the web and positioned so that it would show up in the bottom left corner of the image. Flash was turned on. Once a satisfactory photo was taken, I moved back towards the bike rack. I then positioned myself between the windows of the Student Union and the second pillar of the bike rack structure. The camera was pointed directly at the location of the web. The shot was framed so that the air filtration unit was at the center. Finally, the second photo was captured.

Northern Blotting Analysis is a procedure used to detect a specific RNA molecule/specific group of RNA molecules within a larger group of RNA molecules. It is commonly used in research to study gene expression. It is similar to the Southern blotting Analysis, but detects RNA rather than DNA. First, RNA molecules are extracted, usually from cells. The RNA molecules are then separated by gel electrophoresis, which separates them based on their size. RNA molecules have a negative charge, so they travel towards the positive side. The smaller molecules will travel faster and thus, the molecules will end up in an order than ranges from big to small, from negative to positive. The gel that is used is a formaldehyde gel which denatures the RNA so that it is single-stranded rather than double stranded, so that it can be effectively probed later on. Next, a blotting procedure is used to transfer the RNA from the gel to a membrane, in which the RNA can be probed. The last major step is the probing/hybridization, where a DNA molecule (usually cDNA) with a sequence that is complementary to the desired RNA strand, is used to probe the RNA. Then the excess probes are washed off so that the results can be visualized in an autoradiograph.

Polymorphisms can occur due to many reasons. The main type of polymorphism is RFLP (or restriction fragment length polymorphism). RFLP's are a result of a change of length fragments. They can occur due to SNPs (single nucleotide polymorphism) mutations, Indels (insertion and/or deletions) mutations, or VNTR mutations (variable number of tandem repeats). 

This figure comes from “The Journal of AIDS Research and Human Retroviruses” under the section  “Short Communication Decresed Incidence of Dual Infections in South African Subtype C-Infected Women Compared to Chorts Ten Years Earlier.” I found this figure to be particularly fascinating because of the way it arranged the four groups of data to use space efficiently while still being easy to look at and follow. This figure does a great job of flowing through the panels and getting the information presented in a clear and concise manor. The legend below also does a good job of explaining the details put forth and walking the reader through the datawithout overwhelming them with information.

One of the key aspects of chemistry and in turn the fields that employ chemistry, such as biology, environmental science and medicine, is the idea behind the structure of a compound giving that compound its properties. The structure of a molecule can be done in multiple ways. It can describe the molecular formula, the relative sizes of atoms in the molecule and their shapes, any functional groups that molecule may have, or the spatial relations between the atoms such as chirality. All these characteristics of structure can then relate to the molecules properties. These properties can be chemical, physical or bilogical.

Chemical properties explains steric effects, polar effects and electrostatic effects. These properties deal with reaction rates and position of equilibrium. Chemical properties involve the interaction of the molecule with another. Physical properties involve just the molecule at hand. These properties include the boiling and melting points and solubility. Biological properties are a subset of chemical properties, but they involve interacting with a biological chemical such as an enzyme. Since different molecule have different structures, they fit in biological receptors differently and cause different neural responses. These properties include color, odor, taste, and toxicity.

Chondrichtyes are a class of cartilaginous fish and contains two subclasses; the Holocephali and the Elasmobronchii. There are about 40 extant species of Holocephali, one example being the ratfish. The main defining feature of the Holocephali is that they have a holostylic jaw suspension. This means that the upper jaw is fused with the braincase. Holocephali are also oviparous and will lay 1-2 eggs at a time. Males will have claspers as well as a frontal tenaculum.

Elasmobrochii includes fish such as sharks, rays and skates. The defining characteristics of Elasmobrochii are their plated gills. These may be on the side of their heads as with sharks, or located ventrally in the rays and skates. This distinction seperates rays and skates into a subgroup called Batoids. Elasmobrachi have placoid scales, that are similar to teeth like structures. In fact, they have a pulp cavity, an enamel like substance that coats them and are even made of dentin, as teeth are. Furthermore, rather than teeth plates, these have polyphydont dentitions.

A neuron is a specialized cells that transmits nerve signals. The nervous system has two parts, the central nervous system and the peripheral nervous system. The central nervous system is what acts as the integrating signal. The peripheral nervous system then is further broken down into two parts, the sensory division which sends signals to the CNS through afferent neurons. The other part is the efferent nervous system which takes the signals from the CNS to the target cells via efferent signals. Efferent signals are what leave. Afferent is responsible for the input of signals to the CNS from somatic, special, and visceral signals. Efferent is responsable for the output from the CNS. Efferent signals then go to either somatic or autonomic controls, autonomic are the things in which you cannot control. 

The neuron itself is made up of a couple different parts. The dendrites are what recieve the signals, they either recieve nuerontransmitters or hormones. The dendrites extend from the cell body, which is where everything is made. The nucleus is found in the cell body. The signals are integrated in the axon hillock, which is near the edge of the cell body and this is where the action potential is generated. The action potentials are propagated in the axon and the neurontransmitters are released in the presynaptic terminal. This is the basic structure of a neuron.