Drafts

Molecules encounter strain when their chemical structure experiences some stress which leads to an increase in its internal energy. A strained molecule therefore has a greater amount of internal energy than an unstrained molecule, and only the bonds holding the molecule together prevent the release of this potential energy. Two types of strain are steric strain and torsional strain. Steric strain (also known as Van der Waals strain) occurs when atoms are forced closer together than is allowed by their Van der Waals radii allow. The size of the groups that interact determines the amount of steric strain on the molecule. Torsional strain is dependent on conformation, and occurs when atoms that are separated by three bonds are put in an eclipsed conformation instead of a staggered conformation. This brings the atoms into close proximity and increases their potential energy, which makes the conformation unstable. Torsional strain can resist bond rotation.

Altruism is the principle or practice of selfless concern for the well-being of others. The paper The Evolution of Eusociality argues that the kin selection theory, which refers to the evolutionary strategy that favors the reproductive success of an organism's relatives, even at a cost to the organism's own survival and reproduction, is an unnecessary explanation for the evolution of altruistic behavior, or “eusociality”, and proposes alternative hypotheses based on a two-part mathematical analysis. Kin selection is based on inclusive fitness, which states that organisms can accrue reproductive benefits by helping their relatives. In doing so, they help shared genes to survive and be inherited by the next generation. Thus eusociality can evolve. However, the authors of this paper argue that inclusive fitness is unnecessary to explain eusociality. They observed ants to calculate which of two behaviours, defection or cooperation, would become more prevalent in a population through standard natural selection. They determined that inclusive fitness delivers the same result only in a limited, unrealistic solutions. When the inclusive fitness theory worked, it had no greater success than that derived from standard natural selection. The second mathematical analysis, investigated the manner in which eusociality could evolve through standard natural selection. The authors observed that whether or not eusociality evolves is dependent on the size of the ant colony and how this affects the mortality and fertility of the queen. The authors concluded that eusociality could evolve with some difficulty but is “very stable once established.”

Euthanasia refers to the practice of intentionally ending a life in the event of intolerable pain and suffering caused by an illness. This broad definition leaves room for different categories of euthanasia. It can be physician assisted or patient administered, it can be actively or passively administered on the patient, and it can involve direct or indirect assistance. This argument will focus specifically on the the morality of physician assisted suicide or voluntary euthanasia. When euthanasia is voluntary, the patient requests for the termination of their own life. When euthanasia is physician assisted, a physician carries out a procedure that terminates the suffering patient’s life.

Both physician assisted suicide and voluntary euthanasia are controversial from a moral standpoint. In order to assume a stance, one must consider and rank the importance of certain values such as the worth of preserving life, the degree of patient autonomy, and the external conditions that would justify death. There are many controversial questions that arise such as: Do patients have a right to die, and conversely do physicians have the right to kill their patients? Is it fair for patients to live against their will? Is preserving a patient’s life more important then their choice to live or die?

Nissl stained neurons viewed under 100x magnification in the ventral horn of a mouse. The general shape and cellular pattern is visible, along with some glial cells as well. Image provided by Flickr, uploaded by Berkshire Community College.  

Figure 1. Juvenile penguins. Feathers exhibit dull color patterns. The front is grey and the backside of the penguins is white. There is black on the outside of the head and on the beak. 

Available at: https://farm5.staticflickr.com/4014/4696423445_4705431d8f_z_d.jpg by Ron Hopkins

I am currently taking a biochemistry course. And I am just learning that there is way more to amino acids than I previously thought. I took cellular and molecular biology and we talked about how there were polar and nonpolar, hydrophobic and hydrophilic amino acids, etc. But I never knew how many different properties could go into changing amino acid structure and how that would ultimately change a protein's structure and function. When amino acids are in an acidic environment both alpha groups (amino and carboxyl) are deprotonated. When they are at a physiological pH of approximately 7 then only the amino group is protonated while the carboxyl group is still deprotonated. Then when amino acids are in a very basic environment both the amino and carboxyl groups are protonated. This will affect how these amino acids interact with one another and how they come together to form a structure. When these structures or chains of amino acids come together and fold up and join other folded up chains they function as proteins. But whether or not the protein is in a basic or an acidic environment affects how it’s monomers, the amino acids, are behaving. This is part of the reason why it is so crucial for your body to maintain a constant pH as to not interrupt or disturb the function of many different proteins.

The main function of the nervous and endocrine system is communication between tissues. The two systems work to complete that function in different ways. The nervous system acts fast to make localized responses, while the endocrine system is slow and makes global responses. The nervous system typicially responds to one area of the body. For example, skeletal muscle will react to a stimuli and imediately illicit a responses. The endocrine system releases hormones into the blood stream. They circulate the body and activate cells with receptors for that horomone. 

Probability is the chance of an event occuring. In genetics, probability plays a significant role during crosses to predict outcomes. In class, students looked at an example where a female gray cat mates with a gray male cat. The black coat color is dominant over the gray coat color in the cross. The parents produce a gray female kitten in a litter of six kittens, what is the probability that there are three blacks kittens and three gray kittens? We know that the mother is black and she must be heterozygous because they produce a kitten that is gray. In order to find the probability of three black kittens and three gray kittens, we have to use the binomial expansion for n=6 and then the equation 20p3q3. Once all the values are plugged into the equation, the chi-square will calculate the goodness of fit. The null hypothesis can then be accepted or rejected based on the probability outcome.

There are 8 different types of blood. These types of blood are classifed by the receptors found on their plasma membranes. Red blood cells can have 3 different receptors: A, B, and/or Rh. Different blood types are very specific in reconizing "self" from foriegn substances. Blood types that do not contain a specific type of receptor have antibodies against those receptors. If another type of blood was transfused, the antibodies would attack the foriegn blood. Blood type O- is the universal donor because it lacks all receptors, while blood type AB+ can only donate to AB+ blood. However, AB+ blood can recieve blood from all other types of blood because it does not have any antibodies.  Blood types that have antibodies against a certain type of receptor cannot recive blood from a blood type with that receptor. Likewise, blood that has certain receptors cannot donate to blood that has antibodies against that type of receptor. 

The interspecific interaction I will be documenting is between humans and grass.  Despite the fact that there are an abundance of paved sidewalks on campus, students still feel the need to walk over the grass in very specific patterns.  This leads to the grass being matted down and even uprooted, leaving distinct dirt paths cutting through otherwise grassy fields. A good example of this is a position just north of the student union and just east of the parking garage.  Just looking at a map, one can tell that the humans benefit because they save time. However, the grass does seem to have one mechanism of defense. If it is saturated with water, it will be muddy, and humans will be less inclined to trample it because doing so would damage their shoes.