Genes and DNA!

            We are in the midst of creating a science symposium for the Grade 7’s of our school. It involves the performing of a lab, presenting of information, and assessing of skills obtained. My partner and I are doing our project on the subject of Genes and DNA, and performing an experiment that will be extracting the actual DNA from strawberries using the scientific properties of dish soap, rubbing alcohol, and DNA.

We learned many interesting things while doing our research. A human body is made up of 50 000 000 000 000 cells that all function differently in our bodies. Inside cells are a nucleus which contains 99.9% of our genes. Genes are a part of long molecules in our bodies called DNA (Deoxyribonucleic Acid). If you lined up your entire DNA, it would be at least 6 feet in length. DNA is composed of sugar, phosphate, and 4 bases (Adenine, Thymine, Cytosine, and Guanin) which determine your genetic code. Genes determine how a cell functions and what traits it expresses. The molecules of DNA with your genes are organized into chromosomes; all species have different numbers of chromosomes. Interestingly, humans have two sets of 23, chimpanzees have two sets of 24, chickens have two sets of 39, and bananas have two sets of 11. It is also known that humans share 98.5% of their DNA with chimpanzees, and 99.5% with every other human. This made me realize how alike each person actually is, even though people usually focus on the differences. SNP’s are the imperfections in our base pairs of chromosomes that make us different from one another. It is a variation in base pairs, of Single Nucleotide Polymorphism. Sometimes a single base pair gets added, left out, or substituted. When a base pair gets substituted, this is called an SNP. There are around 10 million SNP’s in the human genome which account for the differences between everyone on Earth. They can affect our physical traits, how we acquire diseases, or how we respond to medication. The number of differences between your DNA and your friend’s DNA can tell you how closely you are related.  Our observable traits are called phenotypes, and result from a combination of your genes and your environment. This interaction starts in the womb and continues through your life. Differences, for example, in height, are determined mostly by genes, but nutrition does have some effect. Weight is also determined by both genes, but more by your diet (environmental). It is less understood how genes determine your personality. Scientists are learning how SNP’s help to determine or affect your phenotype.

DNA is not only important to us because it makes us who we are, but it can also be studied by scientists, who can use the DNA in your body to help it function properly, to make new medicines, to genetically modify foods, or to figure out a suspect of a crime. This can be done through a process of DNA extraction. We will then be performing an experiment that will help with further understanding of what DNA actually is. In the experiment, the Grade 7's will be ablt to visibly see clumps of DNA that exist in strawberries and that contain all the genetic material essential to make a strawberry a strawberry. Strawberries from the grocery store will be used because they have 8 copies of each chromosome, so they are a great source of DNA. During this experiment, we are going to break open the cells of the strawberry and then separate out and clump together the DNA from the strawberry cells so that it is visible to the eye. In order to burst open the strawberry cells so that the DNA is released, we are going to be adding an extraction solution containing dishwashing liquid, salt, and water. Because DNA is not soluble in alcohol, the DNA strands will clump together so that we will be able to see it.

http://ucbiotech.org/resources/display/files/dna_extraction_from_strawberrie.pdf.  

Motor Construction

            I recently performed a physics lab in which I constructed an electric motor in order to practically understand the principles of magnetism and electricity that make it work.

I found it to be actually really fun and more interesting that I first thought it would be. I chose to make just a simple motor so that I could relate the right hand rule principles and electromagnetism principles to it more easily. A 20 gauge enamel-coated copper wire was wounded around a D cell battery approximately 30 times. The wire was cut and then each free end of the wire was wrapped around the coil twice. This created the main coil of the electric motor. The ends of the wires were pulled out straight. With the coil perpendicular to the table, a razor knife was used to scrape off the enamel insulation layer on one side of the wire. This was done so that the electrical connection to the coil would be disconnected with every half rotation of the coil. Four small holes were drilled into a piece of wood. This was used to create the base structure for the coil. Pliers were used to shape the heavy gauge steel wire into a two supports for the coil. The selection of the heavy gauge steel wire gave enough flexibility to be able to readily shape the coil supports, but was still stable. In addition, the steel wire is a conductor, which is required for the current to reach the coil. The ends of the supports were stuck into the wooden board and two magnets were stacked in the middle of them. The coil was inserted into the supports and the magnets and supports had to be readjusted until the coil was centered over the magnet at an appropriate distance. Finally, the battery clip for the 9 volt battery was hooked up to the steel wire.

When the battery is attached to the steel conductor wires, the current passes flows from the positive to the negative end of the battery. The electricity goes through the coil which leads to the creation of a magnetic field around the coil wire. This creates for a magnetic field around the wire interacting with the magnetic field of the bar magnets underneath. Because of the way the two fields are oriented together, when the electricity passes through, the force pushes one end of the coil upward. When the coil turns far enough, the circuit is broken because the insulated enamel wire is contacting the metal supports, and only the momentum of the coil keeps it moving. When it turns a complete cycle, the connection is once again established, and the same repulsive force pushes the end of the coil upwards again until it is perpendicular to the magnetic field. This cycle repeats with each turn of the coil and creates a motor. The “axel” of the motor (the wires that extend from each end) thus rotate and could be used to perform some mechanical work. Using right hand rule two, I figured out that when the bare copper wire is in contact with the steel wire, the current around the coil turns in a counter clockwise direction. This means that the north pole of the magnet is coming out of the page. Looking at the direction that the wheel turns, the bottom of the coil was repelled upwards by the north end of the magnet.

There were several challenges in building the model. The specific orientation of the coil relative to the magnet was very particular for the motor to properly function. The stripping of the wire needed to be very thorough for a sufficient connection to occur. As well, the coil was not staying perfectly centered above the magnets, so I added one bead on each side of the coil to keep it in place. Finally, the 20 gauge wire used to make the coil was quite flexible and therefore easy to make a coil, but it made a fairly flimsy axel which requires period reshaping.

This is the website that I used to get the general idea of how to create a motor; it was really helpful! I strongly suggest this website to anyone who is planning to build a simple motor. http://www.sciencebuddies.org/science-fair-projects/project_ideas/Elec_p009.shtml.

Prenatal Pesticide Exposure Leading to Lower IQ?

I recently read an article that talked about a study which was carried out that showed the possibility of pesticides being detrimental to the development of children. This study was done at the University of California, Berkeley’s School of Public Health, and looked at organophosphate pesticides that are commonly used on crops, and their effects on children who had prenatal exposure.

            It was found in the study that ever tenfold increase in the amount of organophosphates detected during a pregnancy was associated with a 5.5 point drop in their overall IQ scores (for 7 year olds). The children with the highest levels of prenatal pesticide exposure scored 7 points lower than children who had the lowest levels of exposure in intelligence tests. This study along with other studies at the Mt. Sinai Medical Center and at Columbia University who also tested the relation between prenatal pesticide exposure and a child’s IQ at age 7, were published in the journal entitled Environmental Health Perspectives. The author of the journal commented on how unusual it is to see this much consistency across populations in terms of the results of their studies. The study also found an association between prenatal pesticide exposure and attention problems in children at age 5.

The study began in 1999, and samples of urine were tested for dialkyl phosphate (DAP) metabolites twice during pregnancy and then regularly after birth from 6 months to 5 years of age. The Wechsler Intelligence Scale for Children was used to assess the cognitive abilities of children at the age of 7, including verbal and perceptual comprehension, memory, and processing speed. Similarly to the overall IQ scores, each of these categories of cognitive development showed a significant decrease in the scores of the children exposed to higher levels of DAPs during the mother’s pregnancy. However, it was also shown that pesticide exposure after birth was not correlated to a child’s IQ; only to the exposure to the fetal brain development.

This is a scary situation because so many people are exposed to pesticides that are used around their homes, schools, and communities. I think it is important for consumers to reduce their use of home pesticides, and realize that these chemicals are not the only option. Fruits and vegetables should also by thoroughly washed, and organic products could be bought as an alternative.

Here is a link to the article that I read, where you can learn more about the study: http://www.sciencedaily.com/releases/2011/04/110421082519.htm.

Reducing Gases in Our Atmosphere: Hybrid Cars

I recently did a chemistry project which was studying air quality and the either positive or negative factors that have an effect on air pollution. I was researching hybrid cars, and found it to be very interesting.

When the automobile was first invented the world began to change, as transportation of products and people finally could occur over much greater distances. However, this invention was not without consequence. Oil is one of the earth’s limited fossil fuels that create harmful emissions when burned, including carbon dioxide, carbon monoxide, and nitrogen oxides. Carbon monoxide exposure is directly linked to heart disease, and nitrogen oxides are thought to be at fault for the increase in acid rain. Though carbon dioxide levels are not regulated by the government, high levels of carbon dioxide are released into the atmosphere with the burning of fuel, and are considered to be a major cause of global warming. These gases released from the burning of fuel are called Greenhouse gases and when they collect up in the atmosphere, they contribute to the Greenhouse effect, as the sun’s rays are able to enter the atmosphere but are not able to escape. While electric-powered cars contribute almost no pollution at all to the atmosphere, they can only travel about 50 km before needing to be recharged. As well, it has not yet been shown that fully electric cars can operate effectively in the Canadian winter. With the introduction of hybrid cars came many advantages in terms of pollution to the atmosphere. Hybrid cars use a sophisticated combination of a powerful electric motor and a small gasoline motor. In this way, they combine the advantages of both gasoline powered and electrically powered vehicles, drastically reducing the harmful carbon emissions which are released into the atmosphere and which contribute to the warming of the earth. The two main benefits of using hybrid cars are that they improve fuel efficiency, as well as reducing harmful emissions. They are able to maintain the power associated with a gasoline engine, while contributing to the environmental benefits associated with an electric engine. By reducing fuel consumption by up to 250 gallons per year, hybrid cars are much more environmentally friendly in terms of air pollutants in the atmosphere. It is estimated that most hybrid cars produce ninety percent less harmful emissions into our atmosphere than traditional vehicles do. Though hybrid cars have several environmental benefits, they are also the cause of other environmental costs, including costs of storage and the factor of pollution of their battery components.

As shown, there is no perfect solution to reducing air pollution. Humans have been known to be at fault for the steady warming of the Earth for quite some time, and many people do not consider all the ways in which they can reduce their carbon footprint. Driving a hybrid car is a very effective and relatively simple way to drastically reduce the amount of air pollution in our atmosphere. Hopefully if everyone works to reduce their individual amount of pollution, the air quality on Earth will slowly improve, because our own pollution does not just affect us, but everyone else around the world.

Thank you. If you are interested in learning about more ways that you can reduce your carbon emissions, you can visit this website: http://www.davidsuzuki.org/what-you-can-do/reduce-your-carbon-footprint/

Keys to Long Life

            I recently read an article about a personality study which was used to predict how a long a person’s life would be. The findings of the study were published in the Hudson Street Press, and it was called, “The Longevity Project: Surprising Discoveries for Health and Long Life from the Landmark Eight-Decade Study”.

            In 1921, over 1500 students, about the age of 10, began the study, and information was gathered by a Stanford University psychologist named Louis Terman. The study followed the children throughout their lives, gathering data on their family, social relationships, hobbies, pets, job, education level, and many other details. This most recent study was led by Howard S. Friedman (a psychology professor), and Leslie R. Martin, an alumna from the University of California. Subsequently known as The Longevity Project, this study discovered that a person’s risk of dying could be predicted from a personality characteristics and relationships that were formed in their childhood. Before this study, many factors were assumed to be at fault for a person’s risk of dying, such as anxiety, lack of exercise, lack of religion, lack of social well-being, pessimism, and Type A behavioral traits. These factors were, for the first time, able to be studied long-term. The study consistently became more and more complex, as it went on decades longer than expected, and gathered in hundreds of graduates and undergraduates who helped to gain information on The Longevity Project participants. One of the most surprising results that was found, was that the participants who were the most optimistic, joyful, and upbeat, lived shorter lives than those who were not; in other words, the most cautious and determined individuals were those who were alive and healthy for the longest time. It was suspected that maybe this discovery was due to the fact that happy-go-lucky children tended to take more risks in regards to their health, and were more careless. Though it is difficult for many to accept, it was found that happiness is not a main cause of good health.

            The study showed, interestingly, that marriage is good for men’s health, but has little to no effect on women’s health; men who were in a stable marriage lived years beyond 70, whereas men who experienced divorce or never married rarely lived past 70. Another misconception disproved by this study was that working and stressing too much worsened health; it was instead found that committed and career-oriented men and women lived much longer than laid-back men and women. As well, it was shown that people who feel respected and loved do not live longer than those who do not; however, it is obvious that there are health benefits to having positive social relationships.

            I found this study very interesting because, often, so many people are misinformed by others who accept ideas that are told to them. This study showed some of the major misconceptions that are generally accepted by society in regards to health and long life. I think it is important to realize that it is never too late to decide to pursue a healthier path, and that this can only be done when less time is spent worrying about worrying, and more time is spent acting. I think that once people learn about the long term healthy and unhealthy lifestyles that they follow, they will be better able to maximize the healthy lifestyle patterns. I think small changes to a person’s lifestyle can eventually lead them onto a path to health and long life.

            If anyone would like to read more about this incredible study, here is the link: http://www.sciencedaily.com/releases/2011/03/110311153541.htm.

            Thank you.

Obesity Stigma

             A recent article in the journal “Social Psychology Quarterly” addresses an important issue of stigma that many people may not fully appreciate. When we think about stigma we often think about the discrimination and prejudice that occurs against based on race, gender, or sexual orientation. This article by Markus Schafer discusses the adverse health effects of stigma based on body weight. Nobody would be surprised with the finding that obesity is associated with poor overall health. However, Shafer and colleagues found that obese people who experienced weight related discrimination had even worse health outcomes over time than obese people who did not experience such discrimination. The study was based on a ten year follow up study of 1500 Americans and found that obese people who experienced weight discrimination had the sharpest decline in health function over time.

              Obesity is a major challenge in contemporary North American society. Obesity is defined based on body mass index (BMI); BMI values of 26 – 29 are considered overweight and BMI values 30 and higher are considered obese. The US Centers for Disease Control and Prevention recently reported that 34% of Americans are overweight and another 34% are obese. In Canada a recent large survey found that 36% of the population is overweight and another 23% is obese. Despite the alarmingly high prevalence of obesity, we are constantly bombarded with media images of people who are uniformly slim, attractive, and beautiful. One might think that with the rising rates of obesity in the US and Canada, that anti-fat prejudices would quickly decline, but this does not appear to be the case. Obesity discrimination is one of the last forms of discrimination that society appears to readily accept. Obese people are pre-judged as being lazy, weak-willed, lacking self-control, or having flawed character. In contrast, scientific evidence finds that the causes of obesity are much more complex and include genetic factors, body metabolism, culture, environment, and socioeconomic status, in addition to behavior.

            Shafer’s study shows that in addition to the adverse health effects of obesity, and the negative psychological effects of experiencing discrimination, obese people suffer a further toll on their health as a result of being discriminated against. So, why do people feel that it is acceptable to discriminate against others based on body weight? Perhaps some feel that fat people could decide to lose weight if only they “put their mind to it” (in other words, they are to blame for their own problems). While this kind of thinking seems intuitive on some levels, it is pretty clear that many many obese people have repeatedly tried and failed to lose weight. Many others have successfully lost weight and are unable to maintain their weight loss. Discrimination against any group of people is fundamentally unfair and causes harm to those who experience the discimination and well as causing harm to the society that condones the violation of the rights of any group of people. Hopefully, increasing awareness of the complex causes of obesity and awareness of the negative impacts on those disciminated against will help reduce this unfortunate social stigma.

            Here is a link to the article: http://www.sciencedaily.com/releases/2011/03/110303065211.htm

            Thanks!

Why Are Innocent Suspects Confessing?

            I recently read an article from Science Daily that I found to be very interesting, called “Why Innocent Suspects May Confess to a Crime”. The article was examining the reasons behind people falsely confessing to a crime that they did not commit.

            According to The Innocence Project, out of the 266 post-conviction DNA exonerations over the last 20 years, 25% of them involved a false confession. A study was done by the Iowa State University which tried to understand the reasons for which someone would confess to a crime despite their innocence. The answer came down to short-term versus long-term consequences.

            The first experiment interviewed 81 psychology undergraduates, men and women, about illegal and immoral behaviour. Their admissions and denials were paired with either short-term or long-term consequences, the short-term consequences being a long set of repetitive questions, and the long-term consequences being having to meet with a police officer in a couple months to discuss their answers in full. It was found as a result of this study that the participants made decisions to avoid the proximal (short-term) repetitive questions.

            The second experiment interviewed 143 men and women from Iowa State University in the same manner, except this time, the proximal and distal consequences were reversed (the proximal consequences being going to meet with an officer directly after the interview, and the distal consequences being returning to the lab in a number of weeks to answer repetitive questions). Surprisingly, the results were found to be similar, as the participants tended to accept the long-term effects in order to avoid any short-term annoyances.

            In both experiments the participants responded in a way which eliminated proximal penalties as opposed to distal ones. The researchers think that these results help to explain why an innocent person would confess to a crime which they did not commit. Since DNA evidence is used to exonerate cases which involve atrocious crimes, the innocent suspects assume that the truth will comes out eventually, and that any possibility of long-term consequences like conviction, prison, or even a death sentence, is very unlikely.

Because of this, I think when the suspect weighs the two consequences (proximal and distal) in his/her mind, their behaviour will be shaped in a way that allows them to avoid consequences happening right now, versus the ones that may happen in the future. I think it is wrong that so many people feel the need to falsely confess to a horrible crime that they did not commit, and something must be wrong with the system that it has such a high percentage of suspects being wrongly accused. I see a need for police interrogation methods to change so that it limits these methods from encouraging suspects to make decisions based on gains in the short term, as opposed to telling the truth about their situations.

If anyone is interested in the article, here is a link: http://www.sciencedaily.com/releases/2011/02/110218111825.htm.

Thank you.