Chromosomal Disorder

Chromosomal Disorders are errors in the copying DNA in cells, that are then repeated over and over again throughout the body, causing multiple varieties of diseases or disabilities. Often a symptom of these disorders is delayed development and handicapped mental abilities. For example, Down syndrome, which is caused by an extra copy of the 21st chromosome, causes a slight deformity in the face, slower motor skills, and delayed mental development. Down syndrome is caused by a nondisjunction event, when a chromosome fails to separate while the sperm and egg are forming into a zygote. Interestingly, down syndrome is the only trisomy that is compatible with life, whereas babies with trisomy 13 and 18 have a 1% chance of living beyond 1 year (Down Syndrome 2015). Another example of a chromosomal disorder is Cri-du-chat (cry of the cat), whose name refers to the distinctive cry of children afflicted with this disorder (Cri-du-Chat Syndrome 2015). This disorder is different from Down Syndrome in that its caused by a deletion on chromosome 5, rather than a duplicated chromosome (Cri-du-Chat 2015).

The topic of chromosomal disorders is very interesting to me because it seems like an issue that could potentially be solved in the future with advancements in science. While currently a widespread issue that afflicts millions of people across the world, future technologies could potentially eliminate this malady, giving people a chance at a normal life. Although I do not currently know very much about the intricacies of chromosomal disorders, this is a field that I could potentially be interested in researching further and learning more about. What do you think about the future of chromosomal disorders? Will there ever be a way to ensure the health of babies, even shortly after they are conceived? If so, when do you think it will be widely available?

References:

Cri-du-Chat Syndrome. (2015, January 1). Retrieved February 24, 2015, from http://learn.genetics.utah.edu/content/disorders/chromosomal/cdc/

Down Syndrome. (2015, January 1). Retrieved February 25, 2015, from http://learn.genetics.utah.edu/content/disorders/chromosomal/down/

Sleep Cycles and Sleep Deprivation

Throughout our classes mini-presentations, there were several topics that were introduced to us that i had never heard of and were still very interesting to me. but out of all the topics, the one that grabbed my attention the most was the presentation on sleep cycles, perhaps because it was the most relatable and easiest to understand. As a high school student in the middle of junior year, I could fully appreciate the intricacies and importance of maintaining a consistent and healthy sleep schedule. The article I looked at focused on the issues of sleep deprivation in teenagers who are forced to get less and less sleep because of absurd school hours. Furthermore, it went into the issue of adolescents already requiring more sleep than adults, and how the demands of school can turn them into “walking zombies” (Carpenter 2001). Even though we have countless studies showing that adolescents and teens need 8 – 9 hours of sleep per night, very few children actually hit that mark: “According to Wolfson and Carskadon’s 1998 study, 26 percent of high school students routinely sleep less than 6.5 hours on school nights, and only 15 percent sleep 8.5 hours or more” (Carpenter 2001). Also discussed in this article is the characteristic of adolescence to fall asleep at later hours, which was briefly examined in the groups original presentation study conducted in 1997 found that more physically mature teenagers preferred activities later in the day, which indicated a later time of melatonin increases, something that was also touched on by the group that presented this topic (Carpenter 2001). There is clearly a pervasive issue of sleep deprivation and the constant, unyielding, and relentless grind that students are pushed through each day. The topic of sleep cycles along with sleep deprivation continues to interest me as it will be a huge part of my life, for at least the next 5 or 6 years.

References:

Carpenter, S. (2001, October 1). Sleep deprivation may be undermining teen health. Retrieved December 17, 2014, from http://www.apa.org/monitor/oct01/sleepteen.aspx

Reflection Blog: How Gravity Affects Plant Growth

The seeds that we are currently growing in class reminded me of an experiment I did in elementary school for the science fair, where I tested how gravity affected the way a plant grew. The question was, once allowed to sprout, if the sprouts were inverted, how would they continue to grow? Down or up? My hypothesis at the time was that they would continue to grow downwards since I thought that plants didn’t have anyway of sensing which direction they were facing. I set up several seeds in CD cases with wet paper towels, in a set up very similar to the one below, and place several seeds inside the case. Once the seeds sprouted and began to grow, I took the paper towel and flipped over 180 degrees so that the top of the plants now were on the bottom. Then I waited for the plants to grow a noticeable amount so I could visually see where they were growing. To my surprise, after a week or so, the plants had begun to curve back upwards, going either left or right to turn around and grow in the correct direction. Obviously this perplexed me; how could those brainless plants sense which way was up and which way was down?

I did a little research on the topic and this is what I learned:

A plants ability to sense what direction it is growing with respect to gravity is called gravitropism. This is defined as ” the downward growth of the plant root so it can explore the soil better for nutrients and water and the upward growth of the plant shoots to maximize light absorption” (Hund, 2014). While this may seem like a simple response, it actually involves the coordination of several different types of tissues and cells (Hund, 2014). The most popular hypothesis is currently that the cytoskeleton plays a major role in this response, which enables the movement of materials along the plant (Hund, 2014). Even though my initial hypothesis was wrong, I have come a long way since I conducted this experiment and have learned much more. Still, I would like to know more about how a plant senses exactly which way to grow? It it because of different pressures within the cell, i.e. which part of the cell is being pulled down?

Hund, R. (2013, February 4). How plants sense gravity. Retrieved October 28, 2014, from http://www.eurekalert.org/pub_releases/2013-02/ajob-hps020413.php

Coevolution: Bats vs. Moths

As most people know, a very common pairing of predator and prey are bats and insects, specifically, moths. When bats first developed the ability of echolocation, it made it beneficial for insects to have traits that allowed them to stay hidden from the bats echolocation. One trait that moths developed is the ability to detect the frequencies that bats use for echolocation. These organs, called “Tympanal organs”, use a membrane that vibrates in response to sound waves, and convert these vibrations into electrical signals that the moth then perceives as sound (Venema, 2014). Tympanal organs have arisen independently many times in several different lineages, which is not surprising as it provides a very useful ability in survival (Venema, 2014). Another trait that has evolved among moths is the capability of producing a sound that warns bats that it is toxic and unfit for consumption (Venema, 2014). Obviously the pressures of predation have pushed moths to develop many traits that allow them to better survive and pass on their genes. Now it is the bats turn to develop traits to better hunt its prey.

Venema, D. (2013, August 16). Evolution Basics: Coevolution and Predator / Prey “Arms Races” Retrieved October 19, 2014, from http://biologos.org/blog/evolution-basics-coevolution-and-predator-prey-arms-races

Pig extract used to regenerate human muscle

This article describes the results of research completed at University of Pittsburgh School of Medicine, and the experiment that was conducted afterwards. In this experimental procedure, extra cellular matrix derived from a pig bladder was implanted into 5 male participants, all of who had lost at least 25% of their leg muscle volume. These participants underwent physical therapy until their strength plateaued for at least 2 weeks. Then sheets of compressed ECM cells were implanted and designed to fill the injury sites. After around 26 weeks of physical therapy, 3 out of the 5 patients experienced tremendous improvements in strength and function.

Regarding this topic, I had already known that pigs were often used for research in place of humans, because of their similar physiological make-up, and that there was significant research being conducted to find ways to transplant cells or tissues from pigs to humans. However, this topic still interests me greatly because research concerning the recovery of humans will play a significant role in the near future. We have already made great strides in medical technology and have gone a long way towards helping people recover from what were once life-crippling injuries.

Pig extract used to regenerate human muscle, Pitt study shows. (2014, May 5). Retrieved September 14, 2014, from http://www.macroevolution.net/muscle-growth.html#.VBYZPfldXxV