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Some reptiles such as lizards and snake determine their offspring’s sex by chromosomes. However other reptiles like turtles crocodiles and alligators determine their sex based on the environment around them at the time of the egg fertilization. Different environmental temperatures will result in different sexes. A slight change in temperature can result in dramatic differences in determining the offspring. In a given reptile one temperature rang can result in up to 100% reproduction of one sex. In-between temperatures typically result in a mix of sexes. Hormones have a large effect on the temperature sex determination as well. This is due to the enzyme Aromatase which is responsible for converting testosterone into Estrogen. In European pond turtles aromatase activity is low during low temperatures and high during high temperatures. This correlates which the turtles offspring being mainly male during low temperatures and females during high temperatures.

Enzymes work to speed up the rates of reaction. This is done by lowering the activation energy, or the energy needed to reach the transitition state. Activator increased the acitivity of enzymes while inhibitors decrease the activity of enzymes. Inhibitors can be classified as reversible or irreversible. Reversible inhibitors are changes to the enzyme that are not permanet. They include: competitive, uncompetitive, mixed, and noncompetitive (which are a type of mixed). Competitive inhibitor binds to the same place as the substrate, the active site. Inhibition can be overcome at high substrate concentrations. Vmax is not effected but Km increases. Uncompetitive inhibitors bind to the enzyme-substrate complex and cannot be overcome at high substrate concentration. Vmax and Km both decrease. Mixed and noncompetitive inhibitors can bind to the enzyme or the enzyme-substrate. They decrease the Vmax and do not change the Km. Irreversible inhibitors cannot be removed from the enzyme, instead the whole protein would have to be denatured to undo the changes made. 

Vaccines are only as effective as their delivery system. Many vaccines employ the use of adjuvants or additives that help to present the antigen (pathogen that triggers an immune response) to the host’s immune system. Adjuvants are used in vaccines today primarily because of the way that vaccines are produced. In the past vaccines were made by using killed or weakened whole cells, now they are made with parts of the antigen that produce strong immune responses. The part of the antigens that are used in vaccines are most commonly protein components of the pathogen. These vaccines in most cases are safer and are produced more efficiently. Because only parts of the antigen are being used the parts must be presented to the immune system in a different way. This is why adjuvants are used, to help present just part of an antigen to the host’s immune system. Most modern vaccines contain 25% or less of the active ingredient, parts of the antigen, and the rest is adjuvants to help present the antigen to the immune system. If you are curious about what adjuvants are in the vaccines you are receiving you can visit the the CDC website for a full list of ingredients as this information must legally be disclosed.

https://www.niaid.nih.gov/research/what-vaccine-adjuvant

The Saiga antelope of the Eurasian steppe is perhaps one of the strangest looking ungulates on the planet. Characterized by very distinct bulbous downward facing nostrils along with long pointed horns, the saiga looks like a cross between an elephant and a regular antelope. Unfortunately, as of February 2018, this weird but beautiful mammal remains critically engendered and continues to decline in population. Saiga face an unfortunate gauntlet of factors that are leading to its rapid decline, but arguably the most impactful has been habitat loss due to human agricultural development and climate change coupled with illegal hunting. Recent efforts in Russia and other countries within the saiga's range have decreased poaching rates but climate change and human encroachment continue to decrease available feeding grounds. The rate of decline of this species rivals that of any other animal in terms of the size and speed at which the population fell. In the 1980s there were over a million Saiga on the Eurasian steppe, but in just 30-40 years that number has fallen to under 50,000 with an estimate of the population of S. t. mongolica, a subspecies found only in the Mongolian high plains, being under 750 mature adults worldwide.

The aim of this experiment is to test whether or not two species of the same niche can occupy the same space and coexist. This experiment tests whether or not one of two species would outcompete the other when they both rely on the same resources. By using two floating aquatic plants, Lemna minor and Salvina molesta, two species of the same niche are brought together for the experiment. In nature, when two species of the same niche are brought together, possible outcomes include dominance by one of the species, partitioning of the environment and resources, or co-evolution, in which the species diverge from usage of the same resource. With limited time for the experiment, it is unlikely to observe evolution of the two selected species. It is therefore possible that the species may cohabitate and partition the resources so that they both thrive, or one will out-compete the other. In this experiment, we predict that one of the species will outcompete the other due to useage of the same resources.

          The debate over evolution is divided into two main sides, with detractors of evolutionary theory promoting intelligent design as a counterargument to the Darwinian theory advanced by scientists. Intelligent design is the belief that life, or the universe, did not originate by chance, but rather was designed and created by some intelligent entity, with many of the proponents expressing the belief that the designer is the Christian deity. Intelligent design advocates assert that natural selection could not create the complex biological systems observed in living organisms, because such elaborate and interdependent anatomy must be the deliberate product of an engineer, not random variation and cumulative natural selection as Darwin theorized. In contrast, the biological evolutionary theory describes a gradual change in allele frequency within a population through natural selection and various other mechanisms. In this scientific theory, random mutation results in new variation, the environmental pressures on organisms select for those with the most advantageous traits by allowing them to better survive and reproduce, and this natural selection works alongside other mechanisms to cumulatively cause change in species over time. The key distinction between this and intelligent design is that biological evolution is random and operates blindly, with no foresight or end goal. Meanwhile, intelligent design is entirely based on the idea that an organism’s form follows a deliberate blueprint sketched out by a provident entity who is responsible for the creation of all life.

The article (https://neurosciencenews.com/dopamine-cognitive-ability-10788/) mentions that the right amount of dopamine in the brain will improve cognitive function. Tyrosine is a precursor for dopamine. Tyrosine is a polar amino acid.  An experiment was conducted where participants were given tyrosine juice or a placebo. Then the participants were given a memory task where they viewed a bunch of slides and took note of if there were any replicates. The participants who had an increase in dopamine levels with the tyrosine juice performed at a "faster rate with fewer mistakes". In class I learned that dopamine is responsible for attention and motivation. Participants who had the extra dopamine would have a higher level of attention and would pick up on more details. Also their motivation to complete the task would be higher too. Therefore, the level of dopamine in our system to function at a higher level is not always met. My question is if there is an optimal level of dopamine for the brain to function at that level, why is the brain not constantly producing dopamine to reach that level?

The purpose of this experiment is to assess the effect of caffeine on the development of sea urchins. The gametes of sea urchins were collected and added to different concentrations of caffeine. The rate of development was measured by the fraction of eggs fertilized and cleaved under a microscope over the span of 40 minutes at intervals of 10, 25, and 40 minutes. Results show that sea urchins treated with 0.25 mg of caffeine have faster development than the control. On the other hand, sea urchins treated with 0.5 mg of caffeine have slower development than the control. These results indicate that small amounts of caffeine increase the rate of development, however, excessive amounts of caffeine lower the rate of development.

Amyotrophic Lateral Sclerosis is a neurodegenerative disease that affects nerve cells in both the brain and spinal cord. These neurons are interconnected from the brain to the spinal cord and the spinal cord to our muscles. As these motor neurons progressively die, the ability of our brain to control muscle movement is diminished. With voluntary muscle movement being affected, many patients lose the ability to control simple everyday actions. Scientists around the world have been completing studies towards discovering various treatments for this disease. ALS affects both patients neurologically and physically and that is where my interest in the disease stems from. As I have been completing research regarding muscle function and muscle fatigue, I would love nothing more than to develop a better understanding of ALS and gain first-hand experience in the clinical research and care of the disease in relation to muscle function.