Monday, May 9, 2011

My Knowledge on the Human Body

In 5th grade we learned about the human body, and all of it's different systems. However, I unfortunately do not remember much from that course, which I took about four years a go. There are a few things that still stand out in my mind though. One of the major systems I remember is the journey food goes on when it is broken down. Better known as the digestive system.  The food starts in the stomach where it is broken down by bile. It then travels to the either the large intestine or the small intestine (i'm not sure which comes first) and it is broken down further. In these two places more of the nutritional things that are on the food are taken out and absorbed into cells to travel throughout the body. After it has been completely broken down, and nothing is left but waste, it makes it to the rectum where it waits to be excreted through the anus. The liver, gal bladder, and pancreas do something during that process but I can't remember what they do. I think the gal bladder might release some sort of acid that helps break down the food.



Another system I remember is how the heart works. The heart has two main arteries, which pump oxygenated and deoxygenated blood to their specific places in the body. Deoxygenated blood enters (I think) the left artery and is pumped through to the lungs to be oxygenated. Oxygenated blood is pumped through the right artery and is circulated through the body. There are more parts in each artery, but I can't remember what they are. The heart is the most important muscle in our body, it keeps us alive and moving. It circulates blood that comes in from our lungs all over our body. The lungs are another important part of our bodies. We suck in air through our mouth or nose, it goes through a tube that is behind the tube that brings food to the stomach, and hits the alveoli in the lungs, which send it through to the blood behind waiting to be oxygenated.

Another piece of information I know about the Human Body is that nerves send signals to the brain telling it where to send blood or what to do. When we feel pain a nerve in the distressed area calls up to the brain saying we got hurt. The brain also does many other things like controlling every muscle, artery, and thing that makes up our body. If our brain doesn't work we can't live.

Sadly this is all I can remember about the human body, and what I learned in 5th grade. I am very excited to relearn things about the human body, and learn knew things I didn't know before.

Thursday, April 21, 2011

Homozygus Recessive Tongue Roller... What?

This week we have been learning about Genetics. Specifically allele combinations. An allele is an expression of a gene, and they are expressed in sets of two. There are three types of allele pairs. Each allele gets one gene from one parent and one from the other. The three types are homozygus dominant (GG), this type of allele combination will express the dominant trait, whatever it may be; heterozygus (Gg),this will also express the dominat trait; and homozygus recessive (gg), this is the only allele combination that will express the recessive trait. Part of genetics and allele combinations is that you can cross the the two traits and se what type of off-spring an organism may have. The crossing of one trait is called a monohybrid cross. By crossing allele combinations we can dtermine an organisms genotype and phenotype. An organisms genotype is it's allele combination (GG,Gg, or gg). An organisms phenotype is what it looks like (brown hair, blue eyes, ect.) To figure out the results of a monohybrid cross one can make a Punnett Square.
In the Punnett Square above they are comparing two heterozygus parents. Their off-spring have a 3:1 chance of expressing the dominant triat of which is being compared.

In class we did an experiment where we tested our family members on certain traits that they may or may not have. We also tested ourselves. Then we looked up wether certain traits were dominant or recessive. This helped us figure out our genotypes, and our parents genotypes. I tested my sister (Laura), my mom, my dad, and myself. The traits that I tested are wether or not someone can role their tongue, wether someone has a widows peak, has earlobes that are attached or unattached, and if they have a hitch hikers or non hitch hikers thumb. These are the results:
After getting this information I researched the four different traits to see if they are dominant or not, so that I can find out the genotypes of each of my family members and make a pedigree. From my research I found out that being able to roll your tongue, having an unattached earlobe, having a widows peak, and having a non hitch hikers thumb are dominant traits. From this information I can determine each persons genotype, and I can make a pedigree for each of the different traits. 

Having a widows peak is a dominant trait. Laura doesn't have one, and I do. For Laura to be my sister, and my parents child (which she is) my Dad's genotype has to be Ww (heterozygus), and my mom's genotype has to be ww (homozygus recessive). They have to be this because if my dad was WW then none of his children could not have a widows peak, making it so Laura can't be his child, but she is. Laura's genotype is ww because she doesn't have a widows peak, and mine is Ww because I have one. Since I am a Ww I express the dominant gene (having a widows peak), but I carry the recessive gene (not having a widows peak). So depending on who I marry, my children may not have a widows peak. 
The rest of the genotypes for each trait are: 
Knowing wether a certain trait is dominant or recessive is key in being able to figure out someone's genotype. I encourage you to go home and see if you can figure out your families genotype!

Thursday, March 10, 2011

Homosexuality: A Way of Life or Born This Way?

There is a lot of confusion surrounding homosexuality, and why one person is homosexual and another is heterosexual. For a long time people believed a person was gay because they had a specific “gay gene.” After that theory was disproved, scientists believed that homosexuality was based on genetics. However, now they believe that homosexuality is caused by the hormones we are exposed to in the womb.

The study of identical twins, where one is gay and the other isn’t, makes it harder to prove that genetics are to blame. Identical twins have the exact same genes. Meaning, if genetics are the source of homosexuality, twins will either both be gay or both be straight. However, this is not always the case. Since some pairs of twins have one gay twin and one straight twin, scientists have come up with the conclusion that the hormones children are exposed to in the womb lead to homosexuality. 

In the case of a gay child being born without a twin, scientists have come up with the “Big Brother Theory.” The big brother theory states that the more male older brothers a boy has, his chance of being gay increases by 1/3 each time a new boy is born. This is because of anti-bodies that are made during a woman’s pregnancy with her first son. Her body is basically carrying a foreign species because her immune system has never seen proteins on the boys Y chromosome. The natural response is to make anti-bodies to fight the “invader.” The anti-bodies she creates during her first pregnancy affect the boys she carries after, increasing the chance that they'll be gay. 

 The explanation for one twin being gay and the other not being gay is due to testosterone. The testosterone hormone is an anabolic steroid. Anabolic steroids have properties that develop masculine characteristics in the body. Testosterone masculinizes the body and the brain during pregnancy, and makes a boy a boy. While in the womb, testosterone is formed in the 7th week and released in the 8th week. If a male fetus doesn’t create enough testosterone it can affect the way he thinks. If only enough testosterone is created to masculinize the body, but not enough is created to masculinize the brain, a male will want a male partner because his brain was never masculinized making him want women. A study that helps to prove this theory was covered on a segment of 60 minutes. The specific study that has to do with hormones is the study of Rats. 


The problem to this theory is why one twin absorbs more testosterone than the other. Epigenetics explains this glitch. Epigenetics is the activation and deactivation of certain genes. The activation of certain genes during early development is key in determining sexual preference. A gene in one twin can be exactly the same as a gene in his brother, but the gene is deactivated and not doing anything. Testosterone is a hormone, and hormones send messages from one cell to the other. If there isn’t enough testosterone to send a message to a certain, unidentified gene, telling it to activate then it never will. Genetic activation, and locating the "unidentified gene," might be the answer to why one twin absorbs more testosterone than another. 
           
In conclusion, there is a lot that scientists don’t know about homosexuality. Scientists are coming up with many theories about homosexuality and where it comes from. However, everytime they make a new hypothesis thousands of questions and contradictions arise. At the moment, there are many more questions about homosexuality than there are answers. The study of homosexuality is a confusing, under-funded, and probably an emotionally charged topic. Many gay people most likely do not want their way of life studied and based off of hormones and genes. Being homosexual is a very personal way of life, and one that they don’t want disturbed. However, other homosexuals probably want to know why they are the way they are. I am curious to see how this research, and the response to the research, will play out in the end. As of now, homosexuality is due to both genetics and hormones.

Wednesday, February 23, 2011

Gene Mutations can Prevent Cancer, Instead of Causing It...

In an article on msnbc.com, it explains a recent study of short people living in Ecuador. A small group of short Ecuadorians have a rare disease call Laron Syndrome. Laron syndrome is when two different types of genes in the body are mutated. One gene that is mutated is the one that codes the growth hormone receptor (GHR). This mutations results with a decrease in insulin growth factor 1 (IGF1). High levels of IGF1 lead to cancer and diabetes, but when GHR is mutated it leads to a low amount of IGF1, which resists cancer and diabetes.

Some might say the article was uplifting, but I think it's a little depressing. There are only 250 people worldwide that have this disease, and they are short. I don't want to be short, even if it means getting cancer. It's also very rare to have the disease, so it is unlikely many people will get it naturally. Meaning, scientists will have to create a drug that alters GHR, which is very risky. If they make one mistake the person they are testing the drug on could critically altered forever. Furthermore, even if scientists are to come up with a drug mutating GHR, it'll take them years to create, perfect, and then get approved for public use.

This reading relates to our cancer study because with finds like these, scientists get one step closer to creating a prevention to cancer and diabetes. I'm not completely convinced that a preventative drug will be created, but I do have hope that it will. The only downside to a drug like this is that it does not cure the cancer. The genes are mutated so the body can fight the cancer and are less likely to get it. However, if someone already has cancer, would the drug help their body kill the cancer cells already formed, or can the drug only be used to prevent cancer from forming?

These questions are why I'm not completely sold on this article being hopeful. However, it is a good study, and can maybe be helpful if scientists work at their discovery.

Monday, February 14, 2011

Oral (Mouth) Cancer: My Study & Understanding of the Mouth

This is my essay on oral cancer. It is very long because Oral Cancer is very interesting and I wanted to make sure I covered everything. Enjoy!

Oral Cancer:










Oral cancer kills someone every hour. It is one of the 6th leading cancers in men, infects more than 30,000 Americans each year, and there are 640,000 new cases, every year, worldwide. The median age for diagnosis of oral cancer is 62 years old. Oral cancer infects the mouth, lips, or the back of the throat. In America 100 individuals are diagnosed with oral cancer every day, and in 2010 alone 37,000 people had oral cancer. Of that number 7,880 are dead. A person might have oral cancer if they have one of the following symptoms:  white patches in one’s mouth, or bleeding in the mouth; a sore on the lip, difficulty and pain when swallowing or wearing dentures; a lump in the neck, an earache that doesn’t go away, or numbness of the chin and lower lip. Fortunately, if you have one of these symptoms it’s not likely that you have oral cancer.
            The biggest risk factor for oral cancer is tobacco use. Smoking cigarettes, pipes, cigars, or doing dip and other non-smoking forms of tobacco all result in the same thing: oral cancer. The history of oral cancer is tied very closely to the history of smoking. People smoked a lot in the 40’s and 50’s, which leads to the conclusion that oral cancer was very common during those times. The 60’s were the same as the 40’s, but after the 60’s smoking went down. The amount of new cases and deaths for oral cancer has been going down since 1970, but over the last five years the rate has gone up. In 2007 the amount of people diagnosed with oral cancer went up 11% from the year before.
Other risks are heavy alcohol use, which combined with smoking, makes a person more susceptible to getting oral cancer.  Being exposed to fake, or real sun for too long. The sun causes lip cancer, and the likelihood of getting oral cancer from the sun is greater if the person also smokes. If someone had a type of oral cancer, it is very likely that another type will form. Ten to forty percent of people who have been cured of oral cancer will develop another type of cancer later on in life. Being a male is also a risk for getting oral cancer. Males get oral cancer more than twice as much as females do. Less than 5% of people are diagnosed with oral cancer from an unknown source. The, “unknown source,” could be due to genetics, but scientists aren’t sure because it’s such an uncommon occurrence.
Over the past 25 years Human Papilloma Virus has been attributed to oropharyngeal cancer, which infects the mouth and throat. HPV is transferred by sexual contact, and the cancerous cells are found in the base of the tongue, the back of throat, the tonsils, and the soft palate. Those whose cancer stems from HPV have a higher survival rate than those whose cancer stems from tobacco or alcohol use. Virally caused disease is molecularly different, and people who get cancer from HPV tend to be younger and healthier. When the patients are younger their bodies are stronger, so they have a better chance of fighting off the disease. Also, doctors can give a smaller dose of treatment to the patients, which reduces long-term damage. DNA in the infected cancer cells is less damaged than cells destroyed by alcohol and tobacco.
The main type of oral cancer comes from squamous cell carcinomas. Oropharyngeal cancers are usually squamous cell carcinomas, but not always. Squamous cell carcinomas develop in the mouth in white patches that don’t rub off; the cells spread very quickly. Squamous begins in the flat cells that cover the surface of the mouth, tongue, and lips. Squamos can be a benign tumor on the tongue. However, once the cells break away from the original tumor, and enter the blood stream and lymph vessels, the tumor becomes malignant. The cells spread deep into the tissue as the cancer grows; they attach to different tissues, grow and form tumors, and damage the tissue. Squamous cell carcinomas affect the oral cavity, which is the front of the tongue, gums, the lining of the cheek, under the tongue, on the roof of the mouth, and behind the wisdom teeth. The nicotine and tar in tobacco products change the cell, and causes it to lose heterozygosity at places where tumor suppressor genes are supposed to be. Heterozygosity is an individual organism that has two alleles, which are alternative forms of a gene that rise by mutation, that lead to varying offspring. There are multiple copies of the DNA sequence of oncogenes. 
            There are four different types of treatment for oral cancer, but early detection is the key to survival. If oral cancer is found early enough 90% of the people diagnosed will survive for more than five years. Unfortunately, the cancer spreads so quickly that it isn’t found until it’s in the throat or neck, and people die less than five years after diagnosis.  The type of treatment one is given depends on where the caner began, and how far it’s spread. Surgery can be used to remove a tumor, remove the lymph nodes, or damaged tissue. Removing a small tumor isn’t as harmful to people in the long run as removing a large tumor. If a large tumor is removed the jaw, tongue, or palate might also have to be removed, which leads to difficulty when eating, swallowing, talking, and changes how you look.
            Radiation therapy uses high-energy rays to kill the cancerous cells. It is used before surgery to make a tumor smaller, or used to destroy cancer cells in the area of the tumor. For oral cancer, external radiation therapy is used because it finds the tumor more closely, and kills less healthy tissue. There are a lot of unfortunate side-affects to radiation therapy, such as: ulcers and inflammation in the mouth and throat, dry mouth, which makes it hard to eat and swallow, infection, bleeding gums, dental problems, and it can change the tissues in the mouth.
            Chemotherapy is a drug injected into the veins to kill the cancerous cells. Unfortunately, chemotherapy can also kill healthy cells when looking for the cancerous ones. Targeted therapy uses a type of drug, cetuximab, which binds to the cancerous cells and stops them from spreading and growing. Each type of treatment can be used with the others; surgery can be used with radiation therapy, chemotherapy can be used with radiation therapy, or targeted therapy can be used with chemotherapy and radiation therapy. Chemotherapy and radiation therapy are commonly used once the cancer has spread to the lymph nodes.
            Oral cancer is not a cancer one hears about a lot. However, it is important to know about oral cancer because it does take thousands of lives each year. Oral cancer is an unnecessary cancer that is easily prevented. Being aware of what smoking does, and how it puts you at a high risk of oral cancer, is key to the end of most cases of oral cancer. The diagnosis of oral cancer, and death from it, can be stopped. People can be saved. We need to be aware and learn about oral cancer, stop smoking; and soon enough oral cancer will no longer be a common occurrence.
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Saturday, January 8, 2011

I Want to be a Plant!

Photosynthesis is the process of absorbing light energy from the sun (photons), turning the photons into chemical energy, and storing that chemical energy as sugar. The process is made up of two different components, The Light Reaction and The Calvin Cycle.

The Light Reaction:
The light reaction occurs in the Thylakoid membrane. It is light dependent. In the membrane is a PS2 (photon system), a PS1, and an ATP Synthase. Energy from the photon hits the reaction center in the PS2. The reaction center is where the electrons are kept. The photon excites one of the electrons, which starts it's journey through the membrane. The electron travels to the PS1 and releases enough energy to actively transport an H+ ion across the membrane into the lumen. In the lumen there is a high concentration of H+ ions, which will be sent through the ATP Synthase to turn it and create ATP. The electron will release all it's energy, and then end up at the PS1. At the PS1 an electron will have just been excited by a photon, and the old electron (from the PS2) will need to replace the one that just left. The electron that just left will be sent to release it's energy. However, instead of using the energy to pump an H+ ion across the membrane, all the energy will be caught before it's released, and put into a NADP+, which will become a NADPH.
You are probably wondering how the electron that was in the PS2 is replaced. Part of the PS2 is a place where the oxidation of water occurs. The water is oxidized into Oxygen, Hydrogen protons, and electrons. The electrons go wait in the PS2, and the Oxygen is a byproduct of the Light Reaction.
Inputs 
-water
-light energy (photons)

Outputs
-oxygen
-NADPH
-ATP


The Calvin Cycle:
The Calvin Cycle can be tricky to understand, but the best way to wrap your mind around it is to count Carbons.
Three molecules of CO2 are enter the cycle, and by the help of Rubisco, each carbon joins with a 5 carbon RuBP already in the cycle. Now we have 18 carbons, or 3 six carbon molecules. The six carbon molecules are really unstable so they immediately split into 6 three carbon molecules. These 6 three carbon molecules are going to be re-arranged. Each three carbon molecule is going to receive energy from 1 ATP and 1 NADPH during re-arrangement. That means 6 ATP and 6 NADPH are being used in all. During re-arrangement one 3 carbon molecule will be released from the cycle as a PGAL. Then 3 more ATP will help the other 15 carbons become 3 five carbon RuBP, again. Thus the cycle starts again.


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Inputs:
-3 CO2 (initial input)
-9 ATP (from the light reaction)
-6 NADPH (from the light reaction)

Outputs:
-1 PGAL
-9 ADP
-6 NADP+


As you can see Photosynthesis is amazing. Plants don't waste anything, and they produce oxygen. It doesn't get much better then that. I wish we were as efficient as plants, they rock!