All of the Many (Actually Few) Things I Know About the Human Body

Now that I'm thinking about it, the human body is an amazing thing.  There is so much that it can do as long as it is taken care of.  It can digest food, breath in air and convert it to carbon dioxide, pump blood, lift things, smell things, touch things, see things, and most importantly think.  The coolest part about the human body is the brain and what it can do.  The brain can think anything that it wants to and develop many ideas.  If not for my brain, I would even be able to write this blog post or, for that matter, recall anything that I know about the human body.  Unfortunately, I don't know much about how the brain works, or any other part of the human body.  What I do know though is that the body is made up of many systems.  Each system has a different function and exists to accomplish a specific and unique task.  There are so many systems because there are so many things that we rely on our body to do for us.  Some of the systems I can think of are the nervous system, circulatory system, digestive system, respiratory system, immune system, muscular system, urinary system, and bone system.  I also know that there are some things a body needs to function.  One important thing is exercise.  I'm not exactly sure why this is important but I know it plays a significant role in keeping the human body running smoothly.  Other things include food, oxygen, vitamins, and energy.  I am pretty sure that the vitamins and energy often come from the food but can be acquired in other ways too.  For instance, I think that the body can take in some vitamins from the sun.  Regardless, the process of taking in food and processing it to take advantage of it occurs in the digestive system.  The purpose of the respiratory system is to take in air and use the oxygen in it for the body and produce carbon dioxide.  The urinary system's purpose is to remove waste products from the body.  The muscular system allows the body to move and do strenuous activities.  The immune system protects the body from disease and the circulatory system spreads oxygen in the blood throughout the body to all the other parts and systems.  The nervous system is what recognizes different senses and sends messages to the brain.  Each system can be made up of multiple parts of the body. For instance, the digestive system includes the stomach, large and small intestines, liver and maybe even some others.  There is also the reproductive system which lets the body produce offspring.  Each system contributes to the body in different ways but together they allow it to function as it does.

Photo Links:
http://www.joy2day.com/health/wp-content/uploads/2010/09/body-system.jpg
http://www.human-nervous-system.com/wp-content/uploads/2009/07/human-nervous-system.png

Can you roll your tongue? Well, that's genetics.

Over the past few days we've learned a whole lot about genetics.  We figured out that specific traits that one possesses are not a cross between the traits of his or her parents or just random but actually determined by the combination of genes and alleles.  There are two kinds of alleles: dominant and recessive.  Two dominant alleles paired together is called a homozygous dominant pair and this will obviously express the dominant trait.  A dominant allele paired with a recessive allele also known as a heterozygous pair will express the dominant gene or trait but still carry the recessive trait so that it may be expressed in future generations.  The only way for a recessive gene to be expressed is when there is a homozygous recessive pair or a pair of two recessive alleles.  We did several different tests both in class and at home to see which traits different people possess and, based on their parents traits, what their genotype is for that trait or what is the allele pair that they have.  Weather one possesses a certain trait or not and which kind of trait it may be is known as his or her phenotype. Below is a chart that shows the different phenotypes and genotypes of me and my family.

 Based on the phenotypes for each trait of each of my family members, I was able to determine their genotype for each trait because each allele pair is one of the alleles from your mother's pair for that trait and one from your father's pair for that trait.  Based on the different combinations possible for my brother and I from my mother and father's allele pairs, I could tell what genotypes we have.  For some of the traits however, I was not able to figure out the genotypes because for dominant traits that are present or recessive traits that are not present there are two options for allele pairs and the trait in my parents did not help me figure out which pair each person had for these traits.  I also decided to test for thumb crossing when one intertwines their fingers.  This is a trait that I learned was genetic on the internet and decided to see which thumb each family member puts on top when they intertwine their fingers.  I got the results similar to my Hitch-Hiker thumb results with my mom and I going left over right and my father and brother vice versa.  This means that my mother and I are heterozygous for this trait while my father and brother are homozygous recessive because left over right is a dominant trait.  I think it is really cool how you can figure out ones genotype based on the phenotypes of them and their family and how traits are passed down through Mendelian genetics.

GGGGENE TESTING!

Genetic testing is a biological subject of constant research and innovation.  A relatively new procedure, genetic testing is when scientist can test one’s genes to determine the likelihood of the person getting certain genetic disorders by directly examining the strands of DNA for mutations in the sequence.  Any sort of sample can be used including, tissue, blood and hair.  The method of this examination is fairly complex and there are several different ways such genetic testing is preformed.  Sometimes, scientists use probes, which are short strands of DNA complementary to certain mutated strands that can lead to certain disorders and diseases.  Once placed in the body, these probes will find and flag any complementary mutated DNA strands if they are present in the human genome.  This means that using probes in gene testing only tests for specific disorders and diseases.  Another method of testing includes determining the DNA based on enzymes and other proteins because the nucleotide sequence of DNA determines the primary structure of all proteins.  This can tell scientists what DNA a person has and alert them of any mutations.  Gene testing can often lead to gene therapy where mutated DNA strands are altered and corrected in order to prevent certain diseases and disorders.  Currently there are over one thousand gene tests that can be preformed, each to test for the risk of a different condition.  Under the Genetic Information Nondiscrimination Act, no health care or insurance can discriminate against someone who has received gene testing.

            Gene testing can do many things for a person.  First of all, as previously mentioned, its main purpose is to determine whether someone will contract certain diseases.  Gene tests can also be used to identify if someone is carrying a certain  disease in one gene but they won't be affected because they are lacking a second gene that would cause them to contract this disease.  This is important because it lets someone know about any recessive disease genes a person has that could get passed down to their children.  If two people, each with a recessive gene that causes the same disease, had a child, this child will have a high risk of contracting the disease.  Gene testing can be used on newborns to alert parents of diseases the child might contract later in life.  It is often used to test people for adult disorders, cancers, and alzheimers before the patient has symptoms.    The genes of an embryo in-vitro can even be tested after fertilization to check for gene abnormalities that could lead to extreme diseases, disorders and mental handicaps.  This can allow parents to avoid having the child through an abortion so that it will not have to face extreme conditions in its lifetime.  When gene testing does show disease in ones future, doctors can often help the patient perform preventative measures.   Testing is also a way to confirm diagnosis and can also help determine specific treatment methods.

In the future, gene testing could make diseases that are fatal once contracted into completely treatable conditions and maybe even curable.  Research is currently being done with a common iron storage disease.  Even now, gene testing can save lives.  The constont monitoring of colon growth in people with familial adenomatous polyposis genes found during gene tests can prevent people from dying.

There are, however, several issues with gene testing.  For one, tests for disorders can sometimes be limited because they only provide a probability of contraction of disease.  The tests might give a high probability but people still sometimes never contract the conditions.  Gene mutation is also not the only thing that causes these conditions and combinations of genes and environmental factors often play an important role.  These tests are also sometimes considered immoral because of the anxiety they can create when high risk is determined.  Sometimes it is just better to know about a disease when you contract it, especially if there are no real forms of treatment and no cure.

In a recent genetic testing study scientists determined that it is possible to test genes in fluid and tissue samples around the fetus for mutations that lead to down syndrome in the child.  This new method is safer, cheaper, and faster and can lead to the decision of abortion so that the parents will not have a child that suffers from down syndrome.  The reliability of this new test is still being confirmed but it should be in use within two years.  Genetic testing is also helping those who contract scoliosis.  Although this disease is incurable, personal gene tests can determine specific treatment for each case and allow patients to begin treatment before the effects of scoliosis begin.  These are some of the ways that gene testing is helping people in different ways each day.

http://www.ornl.gov/sci/techresources/Human_Genome/medicine/genetest.shtml

http://www.myhealthnewsdaily.com/down-syndrome-fetal-test-maternal-blood-1241/

http://www.einnews.com/247pr/199858

Laron Syndrome - Imunity to Cancer?

I found this article about Ecuadorians with Laron Syndrome really fascinating.  It talks about how those with this syndrome have stunted growth but at the same time, the genes that cause the syndrome give these people immunity to cancer and diabetes.  This was first discovered by a scientist studying one hundred or so Ecuadorians with this condition who noticed that not one of them had ever had cancer or diabetes although the area where they all lived had high numbers of cancer and diabetes victims.  After some studies he finally learned why this was happening.  He soon discovered also that this condition first originated in Ecuador when some European carried it over many years ago.  I am amazed by all of this and the first thing that came to mind after reading this was if somehow people who don’t have the syndrome could use these genes to prevent cancer and diabetes.  This syndrome happens when there is a mutation in a certain gene that codes for growth hormone receptor and eventually produces lower amounts of IGF1, a growth factor. Because high levels of IGF1 can lead to cancer and diabetes, these low levels result in immunity.  I think it would be so great if we could cause this mutation in the gene in all humans so that everybody could be immune to these diseases.  All it takes is some research to see how this gene mutates and if it would be possible to simulate this mutation in those without the syndrome or if there is another way to decrease the levels of IGF1 while at the same time not resulting in stunted growth.  Specifically, there is a case of a young Ecuadorian that has Larons while her sisters do not even though they carry the same gene. It sounds like it is really difficult to figure out about how this could lead to prevention of cancer and diabetes, but if such a discovery is made, so many lives would be saved.   Tests and experiments should be made very carefully though because based on this article, it sounds like badly done tests could be very harmful to the body.  Tests are already being carried out in mice to test the effects of this condition and lack of IGF1.  In the future, drugs that cause this mutation of the gene could become common and lead to at least major prevention if not a cure.

http://abcnews.go.com/video/playerIndex?id=6303784

Cancer Cells of the Stomach

There are many types of cancer but one of the most horrible kinds is stomach cancer also known as gastric cancer. It is the fourth most common cancer in the world with 21,000 new cases in 2010 and 10,570 deaths according to the National Cancer Institute. It is most common in people in their sixties and seventies and is much more commonly found in men than women with approximately 13,000 men diagnosed in 2010 and 8000 women. Once diagnosed, 26% of people will survive the next five years if the cancer has already spread in the process of metastasis as most often the case is and 63% will survive if it is caught before metastasis has occurred. Thankfully, mortality rates are slowly decreasing across the world with developments in medicines and treatments everywhere.

There are five main types of gastric cancer. The most common of the five is gastric adenocarcinoma, which is the kind in 90% to 95% of stomach cancer cases. It occurs in glandular tissues around the stomach. Intestinal Adenocarcinoma is in tissues near the intestines and most common in those over 80 while diffuse adenocarcinoma is more likely to found in younger patients with blood type A. The remaining four types of stomach cancer are all much more rare. Gastrointestinal lymphoma is found in the immune system tissue of the stomach wall. Gastrointestinal leomysarcoma happens in the muscle layer of the stomach and often doesn’t spread to the lymph nodes. On the other hand, Gastrointestinal Stomal Tumors form in tissues that support the digestive organs when intestinal cells of Cajal are present. The last type, gastrointestinal carcinoid tumors, forms in the stomach tissues that produce hormones and this kind rarely metastizes and spread.

Stomach cancer is often unavoidable but there are some things that can encourage cancerous cell growth and some preventative measures that can be taken although not extremely effective. Smoking has been shown to be linked to gastric cancer and because of this, avoiding smoking is one of the preventative measures that can be taken. Lots of salt and not enough fruits and vegetables also increases the risk so it is good to stay away from salty foods and eat lots of fruits and vegetables because vitamin C is known to decrease the risk. A major cause of gastric cancer is the bacteria Helicobacter pylori (H. pylori), which can grow in the stomach and lead to the growth of cancerous cells. These bacteria are able to remain in the stomach often unnoticed. Although it doesn’t always lead to a case of stomach cancer, this is a very important and common risk factor.

The biggest cause of stomach cancer is genetic. Stomach cancer is largely hereditary meaning that it comes from genes passed down from parent to child. The mutations of these gene’s can lead to the uncontrollable growth of cancer cells in the stomach. Specifically, there are three main genes that can cause gastric cancer. CDH1, a gene that produces proteins that allow cells to adhere to each other and form tissues, acts as a tumor suppressor (a gene that checks to make sure that no problems occurred in the cell cycle and cell division). When this gene mutates, it doesn’t do its job of checking for problems, which can lead to continuous production of cancerous cells without being stopped. Another tumor suppressor gene, TP53, can cause gastric cancer for the same reason when it has mutated, is inactive, or is absent from the area. This happens in 80% of stomach cancer patients. The mutation of APC, a third tumor suppressor gene that also acts as a cell signaler, leads to gastric cancer as well. It mutates in only 25% of gastric adenocarcinoma cases but can mutate in as often as 60% of intestinal stomach cancers.

Another thing that can end up leading to cancer is cyclins. A cyclin is a protein that activates enzymes known as kinases. Kinases then tell a cell to continue on in the cell cycle and divide. Cyclin E in particular is sometimes overexpressed by 20% to 30% and this can lead to the constant production of cancerous cells. When this cyclin activates many kinases and they tell the cells to keep on dividing without stopping, then cancerous stomach tumors grow.

Once someone has a stomach cancer tumor growing inside them, there are several different symptoms that can identify it. They include pains and discomfort in the stomach, nausea and vomiting, swallowing difficulties, weight loss, feeling full even after eating a small meal, vomiting blood, and having bloody stool. These symptoms are not definitive however because they can be found as signs of other diseases as well. This means that if such symptoms are identified, the patient should see a doctor before drawing any conclusions.

In order to diagnose someone with stomach cancer, a gastroenterologist may use several methods. First of all he might feel the abdomen for any abnormalities including swollenness of the lymph nodes. He also might perform an endoscopy where a camera is sent through the mouth and numb esophagus to look inside the stomach for any tumors. A biopsy might also be preformed in which the doctor would use an attachment of the endoscope to remove some tissue. This tissue sample could then be examined for cancer cells.

If the gastroenterologist determines that a patient truly does have stomach cancer, the tumor and cancerous cells must be staged. The purpose of this staging is to determine the best treatment for the patient. The stage of a cancerous tumor is based off of several factors, mainly the tumor itself, the lymph nodes around it, and the amount of metastasis that has taken place. A combination of all these factors determines which stage the cancer is in. Diagnosis tests show the state of each of these factors and help doctors stage the cancer.

The most common method of treatment for stomach cancer at an early stage is surgery. This always involves removal of the tumor. A gastrectomy not only removes the tumor but also the entire stomach. Partial or subtotal gastrectomys are also preformed and this is where only part of the stomach is removed. A third type of surgery that can be used to treat stomach cancer is a resection where the specific tumor is removed along with the surrounding tissues. Each of these methods also normally removes the lymph nodes around the tumor. When such surgery is preformed, the doctors always check back to make sure that the entire tumor was removed and no cancerous cells were left in the body.

Another way that gastric cancer can be treated is using radiation. This is when radiation waves are sent into the body to damage and kill cancer cells. This form of treatment involves repeated radiation sessions and doses for months. The kind of radiation used for stomach cancer is known as external radiation in which a machine directs radiation to the cancerous cells and tumor in the body using a ray. This ray is very direct and specifically pointed so as not to effect places uninhabited by cancerous cells. Radiation doesn’t usually kill noncancerous cells although sometimes it can but all efforts are made to direct it only at cancerous tumors. There unfortunately can be side effects to radiation.

A final method of treatment for gastric cancer is chemotherapy. Medicine and drugs are given to the patient to kill the cancer cells as they divide. They do this by interfering with DNA replication, messing up the spindle fibers that pull apart chromosomes, and damaging DNA. This, as with radiation can have an effect on noncancerous cells but, in the same way, rarely does.

As shown, gastric cancer is a horrible form of constantly dividing cells that form tumors and strongly affects tens of thousands of human beings each year. Although there is not yet a cure for this form of cancer, scientists are working hard to protect and save the lives of those with stomach cancer.

Stomach (Gastric) Cancer

• http://www.cancer.gov/cancertopics/wyntk/stomach
• http://www.cancer.net/patient/Cancer+Types/Stomach+Cancer?sectionTitle=Overview
• http://www.cancer.gov/cancertopics/pdq/prevention/gastric/HealthProfessional/page2
• http://www.omnimedicalsearch.com/conditions-diseases/stomach-cancer-types.html
• http://www.cancerquest.org/gastric-cancer-introduction
• http://www.cancerquest.org/cancer-treatment-surgery
• http://www.cancerquest.org/demo/ACS/RT/RadiationTherapy_V2.swf
• http://www.cancerquest.org/chemotherapy-introduction
• http://www.cancer.gov/cancertopics/factsheet/Risk/h-pylori-cancer
• http://www.biology-online.org/articles/cellular_molecular_aspects_gastric/molecular_mechanisms_gastric_carcinogenesis.html

That Amazing Process We Call Photosynthesis!

This week we have been learning about an amazing process that goes on in plant cells known as photosynthesis.  This process uses the suns energy to make energy for the plant.  In general terms, what happens in photosynthesis begins with the chlorophyll in chloroplasts in a plant cell absorbing the suns rays or photons.  Then they convert the light energy into chemical energy which they can store as sugars at the end of this process.  There are two parts to achieving this.  They are the light reactions and the Calvin cycle which is light independent.  One of the amazing things about this process is that it is, as far as I know the only one that can oxidize water molecules into their electron, proton and oxygen.  Oxygen is also released when CO2 is oxidized for the use of the carbons.  This oxygen can then be used for our breathing needs.  Another astonishing thing about photosynthesis is the rates at which it happens.  You can learn more about how the two steps in photosynthesis work in this jing video about photosynthesis!



There are somethings however that i think might effect the rates of photosynthesis.  I think that the temperature of the area around the plant might have some effect on it and that plants in different climates might go through photosynthesis more or less. I also believe that the strength of the sunlight would as well as in how intense the sunlight is and whether its coming through clouds or not.

Cellular Respiration Animation and Enactment!!!

This week, Megan, Mayze and I worked on a video project about the steps involved in cellular respiration including glycolysis, fermentation, the krebs cycle, and the electron transport chain.  The video below is the final product of our hard work! We had so much fun making it! I hope you enjoy it!!!

The KREBS CYCLE! A Story of What Happens...

Here is a SUPER COOL sketch fu on what happens in the Krebs Cycle... Check it out!!!

Click here to see it large...

GLYCOLYSIS! A Story of What Happens...

In cellular respiration, there are three parts.  The first of these is called Glycolysis. Check out the Sketch-Fu below to see an INTENSE explanation of how it happens!

To see this larger on Sketchfu.com, click here!

Stickiness of Gecko's Feet

Everybody knows that gecko’s have sticky feet. This is one of the coolest facts about them. They are able to stick and attack or cling to a surface no matter how smooth and unstuck as many times as they want to without loosing their stickiness. This is because their feet are coated in setae. These are microscopic hairs in the shape of a spatula. The reason that their stick never runs out is because the setae clean themselves. This is all done without the use of any fluid adhesives, which Kellar Autumn discovered in 2002. Now, new research from Autumn is showing us that geckos’ feet can be even sticker when they are in a humid environment. They are able to stick to surfaces better because of microscopic water droplets in between the setae and the surface they are attaching to. Capillary action causes the water to adhere to the setae, in turn, softening their feet. This is why the humid environment around geckos can cause a stickier surface on their feet. In his research, Autumn and his fellow scientists gathered samples of the setae and imitated their movement with a “robotoe” machine so it was as it would be on a live gecko. As they tested this in different environments, at different speeds and with different surfaces to attach to, they still couldn’t figure out why humidity increases the stickiness of the setae. It was a graduate student, Michael Proswe, who finally thought he saw a cause of this increase. He realized that the substance that makes up setae, keratain, gets softer in humid environments, he thought to measure the softness of the setae in different conditions. Another scientist, Jonathan Puthoff, then proved using a mathematical model that softness is related to the stickiness of the setae. This showed that instead of what Kellar had predicted, the increased attachment to surfaces was caused by an increase in softness in the setae.

The video below talks about how the setae on gecko's feet work.

The Diseased La Loma Tree Frog - Extinction or Not

More and more frogs are becoming extinct around the world every day while other frogs are continuously added to the extensive lists of endangered species. One of these species is a tree frog called the La Loma tree frog or Hyloscirtus Colymba. One of the most prominent causes of this is a new disease known as chytridiomycosis, which is rapidly spreading throughout this species of frog. Thankfully, the La Loma tree frog may not become extinct yet because of some as successful scientists in Panama. The Panama Amphibian Rescue and Conservation Project (PARCP) recently began breeding this frog despite being tough to care for when raised in captivity. Not a lot of information was known about the care of these frogs so it was difficult to do this but after many attempts, these biologists have succeeded. One biologist that worked with these scientists on the project was Brian Gratwicke from the Smithsonian National Zoo. He used his extensive knowledge of amphibians to work with them to learn about the care of this frog. At the moment there are 28 La Loma frogs residing at the Summit Municipal Park near Panama City along with four tadpoles. These animals are constantly monitored for details of care for future breeding. Breeding is not the only effort being made by the biologists in Panama; they also hope to find a cure to this disease so that they may one day release these frogs into the wild but for now they will keep them protected. These scientists are doing their best to save as many species of frogs as they can and they aim to breed at leas 20 additional frog species in Panama. This will make a small but important dent in the 33% of amphibians in the world that are endangered. The information gained by these scientists will also help to breed and in the end save many other important forest animals from extinction.

You can also check out this cool Prezi about a La Loma tree frog named Phillip.

The La Loma Tree Frog on Prezi

 Here is a video with Brian Gatwicke about his work with amphibian conservation.

Osmoregulation in Marine Iguanas

Marine iguanas like the one to the right often live in the Galapagos Islands spending much of their time in a marine environment.  They therefore are hypertonic to their surroundings so when they consume salt water, they have too high a concentration of salt inside them.  They also gain salt through their main food source, algae in seaweed.   They need isotonic conditions where they have the right concentration of each substance. Unlike some animals they cannot produce a concentrated urine containing salt to let them conserve water and relieve them of all the sodium chloride inside them.  Instead they have adapted to their environment allowing them to regulate the high concentrations of salt.  The primary adaptation that lets them do this involves glads at the top of their heads, above their eyes and noses.  These glands excrete sodium chloride decreasing the concentration of it inside them and releasing salt into the outside environment.  Another gland sorts the salt from the food and water consumed by the iguanas and sends it to the excretion gland.  When they "sneeze" out the salt through their glands, it often lands on the end of their snouts and dries there forming a gross white crust.  This salt sneezing allows marine iguanas to eat and drink what they do without gathering a high sodium chloride concentration inside their bodies.  This regulatory adaptation is what allows them to live in a marine environment because without these excretion glands, a high concentration of salt would build up in the iguanas bodies causing them troubles and maybe even bringing about death.

Below, there are several videos showing marine iguanas using the excretion glands to get rid of salt. 







Research Sites:
- http://www.encyclopedia.com/doc/1G2-3400700323.html
- http://www.cartage.org.lb/en/themes/sciences/zoology/animalphysiology/osmoregulation/osmoregulation.htm
- http://en.wikipedia.org/wiki/Marine_iguanas
- http://www.geo.cornell.edu/geology/GalapagosWWW/MarineIguanas.html

The Upper School as a Eukaryotic Cell

To see this glog in a separate window please click here!

Helicobacter Pylori Bacteria

A bacterium of helicobacter pylori

Helicobacter pylori is kind of bacteria that is harmful to humans.  It is most often found in the stomach on the mucus walls specifically in the antrum and when present, it can cause stomach pains and inflammation of the stomach lining which can lead to ulcers and stomach cancer.  It is usually about 3 micrometers long and in the picture to the right and below, you can see that it is a bacillus bacteria because of its rod shape.  You can also see the flagella coming off the end.  These help the bacteria to move through liquids like lumen in the stomach. However, lumen is acidic and helicobacter pylori survives better in a neutral chemical so when it senses lumen, it swims away to a more neutral part of the stomach.  Ulcers develop in one out of every six people that are infected by the bacteria.  There are several tests that can be used to detect if the bacteria have infected someone.  Once someone is infected by helicobacter pylori it is difficult to kill off the bacteria.  This is because when that person is given antibiotics, the bacteria often develops an immunity to the medicine.  To help avoid this, several antibiotics are often taken at once to decrease the probability of the bacteria developing an immunity.  Another way to get rid of this harmful bacteria is by way of another kind of bacteria,lactobacillus casei.  This bacteria is also found in the stomach near where helicobacter pylori is found and can help to fight against it.

A bacterium of helicobacter pylori

 Sources:
 https://health.google.com/health/ref/Helicobacter+pylori
http://en.wikipedia.org/wiki/Helicobacter_pylori
http://www.medicinenet.com/helicobacter_pylori/article.htm
http://en.wikipedia.org/wiki/Lactobacillus_casei
http://cat.inist.fr/?aModele=afficheN&cpsidt=13896396

Image Sources:
http://nobelprize.org/nobel_prizes/medicine/laureates/2005/press.html
http://i.rosaceans.com/archives/497
http://www.steadyhealth.com/articles/Helicobacter_pylori__The_Bacteria_that_Cause_Ulcers_a71.html

Macromolecules Lab Reflection

In a lab that I completed in biology, I tested for four macromolecules, in a onion while other groups tested for these same macromolecules in other substances.  These four macromolecules were proteins, glucose, starch, and lipids.  To test for each one we used different reagent tests to show if the macromolecules were present or not.  For testing for proteins we used a bright blue biuret solution.  Since the solution turned brown when it was combined with the onion, that meant that there was a presence of proteins.  With the benedict solution, there was glucose if the solution turned a green to orange color.  In the linked picture you can see an example of the color change.  We used a lugols iodine solution to detect starch and rubbed the onion on brown paper to detect lipids.  Me and my partner determined that onions do contain protein and glucose, but starch and lipid macromolecules are not present.  I liked this lab because it was fun preforming each test and seeing if the macromolecules are present or not. Although, these results were a little different from the predictions that we made, I think they were accurate for the most part.  Some of the results to other people's substances surprised me.  For instance, I thought that the lemon would probably have at least one of the four but it ended up having none.  Some were obvious like it was apparent that the strawberry would have glucose because it is sugary and a that potato would have starch.

Nucleic Acids (Jing)

This is a Jing presentation I made about Nucleic Acids.

The Properties of Water

Water has several properties that make it different from other compounds.

Polarity - Water molecules are made up of hydrogen and oxygen atoms which are bonded together by a polar covalent bond.  What a covalent bond means in this case is that electrons are being shared between one oxygen atom and two hydrogen atoms.  It is known as a polar bond because the oxygen atom is larger than the hydrogen atoms so it's using a little bit more of the shared electrons.  This makes the oxygen atom slightly negatively charged and the hydrogen atoms slightly positively charged.

Cohesion - Water molecules are attracted to other water molecules and they often form hydrogen bonds between each other.  This attraction is called cohesion.  In a hydrogen bond, the slightly positively charged hydrogen atoms in one water molecule bond with the slightly negatively charged oxygen atoms from different molecules.  They bond together because they are oppositely charged.  This cohesion is why water droplets form.

Adhesion -  Water molecules are not only attracted to each other but also to the molecules of other compounds.  For example when a straw is placed in a glass of water, the water will rise up the straw above the level of the water in the glass.  This is because the water molecules on the inside edge of the straw are attracted to the straw molecules and then other water molecules come along because of cohesion and their hydrogen bonds.

Surface Tension - At the surface of water (and throughout it) the molecules form hydrogen bonds and adhere to each other.  In order to break these bonds, energy is required so unless energy is applied, then the hydrogen bonds will remain intact.  For instance, when a glass is filled to the brim with water and a little bit more is added it wont spill over the edge because there isnt enough energy being applied.  Another example involves a paper clip.  Normally a paper clip would sink in water but if placed evenly on the surface it will remain at the top.  This is because the paper clip is light enough to not have enough pressure or energy to pierce the strong surface tension caused by adhesion.

Specific Heat - This is the amount of energy required to heat required to raise the temperature of 1 gram of a substance up 1˚C.  Water has a particularly high specific heat so this means that it takes a long time for it to heat up or cool down.  This is why pools, lakes and the ocean are good ways to cool off on hot days because the water doesnt have enough time to get really warm as it sits in the sun.  This also why the time of year when oceans are hottest is the fall because during the summer they slowly heated up and by the fall they haven't cooled down yet and are very slowly loosing heat.

Ionization - This is when water molecules decompose into ions.  The polar covelent bond between two hydrogen atoms and one oxygen atom splits into a positively charged hydrogen ion and a negatively charged  hydrogen and oxygen ion.  This ionization process is constantly happening to water as is the process of the ions bonding back into molecules.

pH - Based on the ionization of water, there are the same amount of positively charged hydrogen ions as negatively charged  hydrogen and oxygen ions, therefore water has a completely neutral density of seven and is neither acidic or basic.

Universal Solvent - The fact that water is constantly ionizing makes water a very good solvent in which many substances will dissolve because when a compound is placed in water the strong ions (decomposed molecules) are able to decompose the atoms of the molecules of the solute.

States or Phases - Water is one of the few substances that can be found in all three states or phases in the natural world (without man-made technology).

Density - The density of water in its liquid state is one gram per milliliter.  The density of most substances (maybe all) in solid form is more than the density in liquid form.  Unusually, water has a lesser density when it is in its solid than in liquid form because when it changes to a solid the polar covalent bonds stabilize and spread out into lattice bonds.  The formation of the molecules in lattice bonds when water is in solid form is shown to the right in the picture above while on the left, the molecule formation of water in liquid form is shown. This means that with the same mass, a sample of water takes up more space in solid form than in liquid form.  Because water has a lesser density in solid form than in liquid form, solid water (ice) floats on liquid water.

Biology Begins!

When I first heard that I was going to be taking biology, I thought that we were going to be learning about animal’s insides.  Now that school has begun, I know that it’s a bit different but I am still very excited about the things that we are going to learn this year.  It is going to be interesting to learn about what cells, genes, and molecules do and the ways they make our bodies work.  Genes sound especially fascinating and I think it would be cool to know how they work.  I also am excited to learn about how new information that is being discovered about these things is helping to prevent and treat diseases.  I think that web tools are going to be very helpful in learning and discussing this information.  Glogster is a fantastic fun-to-use tool that I think will be very useful because it allows one to create a poster that may include videos and other web content.  It is a great way to show a variety of formats of information of a subject.  This course sounds very interesting and I can’t wait to get started.