Drafts

 I took Statistics 240 course with Joanna Jeneralczuk during the fall 2017 semester. Throughout this course I learned about the basics of probability, binomial and normal distributions, Central Limit Theorem, simple linear regression, sampling distribution of the population mean and proportion, how to use the Z and T table, and etc. At the end of this course the core objective was to learn how to analyze data and draw inferences. In addition, to know how to present data graphically and interpret them. As well as recognize whether reported results correlate with the study and analysis conducted. From this course, a key component that was helpful in my other courses was probability since it also became useful in my genetics course. It is a key idea because probability is a component that comes up a lot throughout the biology courses I have taken. It is a topic that is also relevant in our lives. For genetics we had to determine the probability that out of three children one will come out with blue eyes given the parents genotype. 

Our primary focus was to study and survey students attending a four-year college or university. Our sample was random, and we compared majors as well. We asked what kind of major they take, how many credits are required to graduate, and a minimum cost of money that goes into one semester only. The date we collected was illustrated in a histogram give a visual representation of our results and what they mean. A scatterplot was also created to demonstrate whether there is a relationship between the two variables and how they affect one another. It helped us interpret and visually see if college expenses increase as an individual enrolls in more credits in one semester. 

In class we have learned about four different types of operant conditioning.  Operant conditioning works to modify voluntary behavior as a result of consequences and two types were used to train the bees in this experiment.  The first is positive reinforcement, which was used to train the bees to associate extending their proboscis in expectation of a reward.  The researchers conditioned the bees to extend their proboscis only when they smelled sugar water or sugar water mixed with a scent to train them in recognizing the correct scent.  The other type of operant conditioning used in this experiment was punishment, which was used to train bees to associate extending their proboscis to salt water or salt water mixed with a scent with a negative experience.  The bees that extended their proboscis towards salt water would receive a drop of saltwater in the mouth, which was a negative experience.  These two types of conditioning allowed the scientists to train bees to extend their proboscis to sugar water and not to salt water.

            I took introduction to statistics my freshman year here, in this class we learned about probability, random variables, binomials/normal distributions, central limit theorem, hypothesis testing and linear regression. I don’t remember a whole lot since it has been a couple years since I touched this material, however I do remember probability and binomial/normal distribution. Probability comes into play in our everyday lives and has crawled into some of the classes I have taken recently. One being physics, I remember learning about probability in physics in the end of 131 with the probability a certain energy will be located within certain pods in a device or container. We used the same equations as in statistics to figure out the probability of the locations of these energy pockets. Binomial/normal distribution I remember the bell curve which was symmetrical and would give distribution that naturally occurs in situations. With the symmetrical bell shape, this would say the majority of the situations would gather near the middle and fewer of the situation would land in both extremes of the curve. Portions of this curve were divided into standard deviations, and would travel left or right from the center by one standard deviation at a time from the mean.

Depression is becoming more and more common throughout society. This increase in presence has lead to a influx of studies that have lead to many advancements in the treatments of the disease. One specific study has found the beneficial side effects acupuncture has on depression. The study used multiple trials of low and high risk patients in order to test the effects. The study that when paired with medication overall acupuncture ahd a positive effect on relieving stress in the individual. This lowered stress level in turn lead to a decerease in the severity of the depression. 

Protein is one of those fascinating nutrients that allow extremely good for you there is a maximum healthy limit. There has been numerous studies that have proven this but the exact amount of protein that is in fact to much seems to vary study to study. This specific study goes on to discuss the differences in how the body takes in fast-digesting versus slow-digesting protein. In respect to fast-digesting proteins a young adult can take in 20-25g of protein while still maintaing a lean-tissue building process. This is because the fast-digesting proteins lack the surplus of other macronutrients that could hinder the digestion process. Conversely slow-digesting proteins are more likely to contain other macronutrients that can slow down the digestion process meaning a young adult would be able to consume more because of the delay in amino acid uptake. The study concluded in saying that based on the results a human would most benefit from a 1.6 gram of protein per kilogram of body weight per day diet in order to maximize the lean-muscle building process.

Another example of modern convergent evolution is human adaptation to tropical rainforests. Tropical rainforests are harsh environments for humans. They are marked with high pathogen activity, high temperatures and abundant rainfall, as well as ferocious animals. This type of unforgiving environment likely resulted in human adaptations in response to selective pressures. Researchers studied 660,918 SNP’s looking for outliers in populations living in a tropical rainforest and genetically related populations living outside of the tropical rainforest in Africa, North America and South America. “The most significant positive selection signals were found in genes related to lipid metabolism, the immune system, body development, and RNA Polymerase III transcription initiation. The results are discussed in the light of putative tropical forest selective pressures, namely food scarcity, high prevalence of pathogens, difficulty to move, and inefficient thermoregulation (Carlos Amorim et al., 2015).” Researchers identified seven clusters in five separate chromosomes that show positive selection for potential rain forest adaptations. Two of the clusters only showed evidence of positive selection in North America and South America. Two other clusters only showed evidence of positive selection in Africa. The other three clusters were found in both continents. This is clear evidence of convergent evolution in modern human history.

Stem cell research, specifically embryonic stem cell research, poses a moral dilemma to the respect and value of human life, the topic of debate is whether or not the embryo being used has the status of a human person. Many see the embryo as a person or having the potentiality of becoming a person, but this argument is further deconstructed as to what defines personhood, is it defined through mental capabilities or is it a physical state of being. Those who argue in support of this view, state that the development of a fertilized egg into to baby is a continuous process and that any attempt to pinpoint when and where personhood begins is unnecessary. Once the sperm and egg meet the an embryo must be protected.

The question that I chose was “Why does this graph level off?” This question appears in Lecture 10, on slide 12. It also has a diagram of a graph with [substrates] as the x axis and initial velocity as the y axis. The concept that is being tested by this question is the students ability to interpret enzyme activity graphs. In order to to answer this question correctly, you need to understand how to interpret what a changing substrate concentration does to an enzymes Vmax. Understanding what initial velocity means is important. You also need to understand what Vmax means, because knowing that will eliminate some of the incorrect answers. Understanding what would cause an enzyme's rate to slow down would enable you to answer this question.

For this question, the correct answer is B, enzyme active sites are filled. This is correct because the enzyme reaches Vmax when the graph is starting to level off. Vmax is reached when the enzymes in the system are all working at maximum rate, which is when all of the enzymes are filled. Answer A, “the substrate is used up,” is incorrect because where the graph levels off, the substrate concentration is not zero. In addition to that, the y axis is initial velocity, which means there would be no time for the substrate to have been used up. Answer C, “the reaction reaches equilibrium,” is incorrect because the graph makes no mention of the reverse reaction, and thus no mention of equilibrium. The graph only illustrates the rate of the enzymes which are performing the forward reaction. Answer D, “the rate of the reverse reaction becomes significant” is incorrect because that would indicate that the graph illustrates a system over time. The y axis shows that the dots mean initial velocity, which means that the reverse reaction would not have time to become significant.

One of the strengths of this article was the testing of both scent detection and scent discrimination.  Olfactory cues are more complex in nature than what can normally be reconstructed in a lab.  Therefore, the authors’ decided to drive home the hypothesis of olfactory lateralization by testing bees on two different aspects of olfaction. 

One weakness of this study was that during the comparison of olfactory receptor cells each of the 10 pairs of antennae should have come from 10 individuals.  Instead, only 7 pairs came from 7 individuals and the other three from three individuals.  This could cause some data discrepancies because all antennae were not collected in the same manner.  Also, 10 pairs of antennae is not a high number considering they added this information to their paper.  The authors might want to gather more data with more pairs of antennae in order to be entirely sure of the correlations.