msalvucci's blog

Prosocial behavior is defined that the behavior that creates a positive outcome and can include factors of cooperation, communication and helping. This behavior was studied by scientists after the tragedy in New York of a young woman being stabbed on the street while 30 bystanders stood and watched. Scientists questioned why the bystanders did not try to help the young woman in trouble, to which the bystanders stated that they assumed someone else was calling the police. It was determined that the “diffusion of responsibility” led to these bystanders to fail to help in a large crowd. While this information was interesting to scientists, it was not enough to determine why this woman why stabbed so many times without anyone calling for help. This bystander intervention research gives insight to the factors that affect someone’s ability or probability to help another person in danger. Many experiments were designed to study the diffusion of responsibility and how it is affected by different variables. 

The central nervous system consists of the brain and spinal cord. The two types of tissues that makes up the central nervous systems are grey matter and white matter. The grey matter contains the cell bodies as well as dendrites and unmyelinated axons. This gray matter is the processing region of the brain. It also consists of regions in the brain that deal with motor control and sensory perception. These regions affect the senses such as seeing and hearing, as well as self-control, memory, emotions and decision making. White matter is composed of myelinated axons, and their job is to transmit signals between neurons and connect the gray matter areas to each other. Gray matter is typically found near the surface areas of the brain whereas white matter is found in the brain cortex’s inner layer. 

Glycolysis and gluconeogenesis are two glycolytic pathways involving the synthesis and degradation of pyruvate from glucose. Although these reactions look like the opposite of each other, gluconeogenesis actually bypasses three pathways involved in glycolysis. Three irreversible reactions including the enzymes hexokinase, PFK-1, and pyruvate kinase must be bypassed due to their change in free energy. The changes in free energy for these pathways are -33 kJ/mol, -22.2 kJ/mol and -33.2 kJ/mol respectively. When a reaction has a change in free energy that is 0 or close to 0, it is easy to reverse and therefore is used in the process of gluconeogenesis. Being that the changes in free energy for these three pathways in glycolysis have such high negative values, gluconeogenesis must find a way around these reactions in order to degrade pyruvate. Therefore, the reaction uses different enzymes for these three pathways in order to complete the degradation of pyruvate when necessary.

. After letting the participant observe the second card, he went down the line of 7 staged people and asked them which line on the card matched the original card. They told their answer out loud for the rest of the participants to hear. Each participant said the obviously correct answer, including the newest participant. He then repeated this task 3 times. However, on the third trial, the 7 staged participants said the same obviously incorrect answer. This was to test whether the newest participant would say the correct answer, or follow their peers and say the wrong answer despite it being obviously incorrect. As a result, Asch found that at 75% of the participants said the incorrect answer with the rest of the group at least one time throughout the trials. This experiments proved that people can depend on conformity in group settings, seeing as the participant said the incorrect answer when the rest of the 7 group members said it.  It is interesting to see how someone’s answer can be so greatly affected by their group members even when the correct answer is obvious. When the other participants said the incorrect answer, the participant must have questioned their own thoughts or were too nervous to go against the norm. 

Conformity refers to the idea of humans following the actions or behaviors of a group of people that they familiarize themselves with. This concept is most relevant to young teenagers who are trying to figure out their identity or personality as they may be prone to following the actions of their peers in order to fit in. These conforming actions may disagree with one’s true morals or beliefs due to the fear of being different. Solomon Asch’s experiments with conformity help to determine how powerful the idea of conformity is on personality traits in adolescents. His experiments focused on perceptual conformity, a type of conformity that deals with the perception of senses such as taste, touch, and smell. During one of his experiments he had a volunteer sit down next to 7 other staged participants. He then gave each participant the same card and ask them to remember the length of the line on the given card. After he let the participants observe the first card, he took it away and gave them a new card with three lines of differing lengths. One of the lines on the card was clearly the same length as the line on the previous control card. 

Glycolysis and gluconeogenesis are two glycolytic pathways involving the degradation and synthesis of pyruvate from glucose. While these reactions seem like the opposite of each other, gluconeogenesis actually bypasses three pathways involved in glycolysis. The three irreversible reactions must be bypassed due to their change in free energy. The reactions using the enzymes hexokinase, PFK-1, and pyruvate kinase yield a large negative change in free energy making the reaction impossible to reverse. The changes in free energy for the respective pathways are -33 kJ/mol, -22.2 kJ/mol and -33.2 kJ/mol. When a reaction has a change in free energy that is 0 or close to 0, it is easy to reverse and therefore works in the process of gluconeogenesis. However, if the reverse reaction for glycolysis is necessary, the cell uses another pathways and another enzyme to bypass the irreversible change in free energy. Gluconeogenesis is an anabolic pathway because it creates complex molecules from simple molecules. Prior to coupling, the pathway is endergonic and cannot be reversed. 

Carbohydrates are a major source of energy for the human body. These saccharide structures consist of carbon, hydrogen and oxygen. The chains of sugars are connected by glycolytic bonds and can be branched or unbranched. The branching structure of carbohydrates are dependent on the type of bonds attaching the monomers, either alpha (1,4) or alpha (1,6) bonds. The condensation reaction connects two monosaccharides to form a disaccharide. A few examples of disaccharides are maltose, lactose or sucrose. These are saccharides found in the table sugars that are used in cooking and in dairy products. Oligosaccharides, which have 3-10 connected monomers, are usually attached to other proteins in the cell and are important in cell signaling. Additionally, polysaccharides are chains of 20 or more monomers consisting of different types of glyosidic bonds (1,4 or 1,6) within the same chain or branch. 

Metabolic coupling is the process of using energy that is released from an exergonic pathway to provide energy needed for an endergonic pathway. The main goal of metabolic coupling is to end with a negative change in free energy (delta G). A negative change in free energy indicates a spontaneous reaction. Metabolic coupling can exist in three forms: between biochemical pathways, within biochemical pathways and within chemical reactions. Energy transfer within metabolic pathways involves the removal of phosphate groups through hydrolysis, thus resulting in a large negative free energy value. The amount of free energy available in the bond is called the phosphoryl group transfer potential. Phosphorylation is the reverse reaction of adding phosphate groups through the input of energy (ATP).

The electron carrier’s role in energy transfer is to act as a middleman in the transfer of elections between reactions. A typical example of an electron carrier is Nicotinamide Adenine Dinucleotide (NAD⁺), which has an oxidized and reduced form (NADH). The term oxidation refers to the loss of electrons while reduction is the gain of electrons. For every oxidation, there must be a reduction because there cannot be any free electrons in the cell. The oxidized and reduced forms are called the “conjugate base pairs” within a reaction. Reduction potential, or the affinity for electrons, is determined experimentally using a volt meter to measure electron flow. It is related to the H⁺ ions in a reaction; if a reaction has a positive reduction potential, the oxidized form has a higher affinity for the electrons than H⁺. On the other hand, a negative reduction potential has an oxidized form with a lower affinity for electrons than H⁺. Additionally, a transfer of e^- from molecules of low affinity to high affinity releases energy and is spontaneous. 

Metabolic coupling is the process of using energy released from an exergonic pathway to provide energy needed for an endergonic pathway. The main goal of metabolic coupling is to end up with a negative change in free energy (delta G). A negative change in free energy indicates a spontaneous reaction. Metabolic coupling can exist in three forms: between biochemical pathways, within biochemical pathways and within chemical reactions. Energy transfer within metabolic pathways involves the removal of phosphate groups through hydrolysis, thus resulting in a large negative free energy value. The amount of free energy available in the bond is called the phosphoryl group transfer potential. Phosphorylation is the reverse reaction of adding phosphate groups through the input of energy (ATP).