Meat raises lung cancer risk

Summary:

According to the article, people who eat a lot of red meat and processed meats have a higher risk of several types of cancer, including lung cancer and colorectal cancer.

A big study shows that people who eat a lot of meat have a higher risk of liver and esophageal cancer and that men who eat red meat get pancreatic cancer more easily. "The people in the top 20 percent of eating processed meat had a 20 percent higher risk of colorectal cancer -- mostly rectal cancer -- and a 16 percent higher risk for lung cancer."

Meats can cause cancer by several routes. They are both sources of saturated fat and iron, which have independently been associated with carcinogenesis. Meat is also a source of several chemicals known to cause DNA mutations, including N-nitroso compounds (NOCs), heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs).


Reflection:

Have you ever thought of the meat you eat daily may lead to cancer? Yes, cancer! All kinds of red and processed meat may be a cause of cancer. Red meat included all types of beef, pork and lamb. Processed meat included bacon, red meat sausage, poultry sausage, luncheon meats, cold cuts, ham and most types of hot dogs including turkey dogs. All these meats should be familiar to you because you eat them every day.

I was totally shocked when I first looked at this article. It is unbelievable that the meats in the hamburgers and sandwiches give people a higher risk of getting cancer. The thing that makes me less worried is that I don't eat a lot of meats. I prefer vegetables to meats.

I think statistics do show that meat really increases the chances of getting cancer. Meat is also a cause of DNA mutations. However, meat is a part of our lives. Every day, you need vegetables and meats to meet a balanced diet. Is it possible to make everyone stop eating meat?

In my opinion, the best way now is to limit the amount of meat we eat each day. I think everything is good if you use it in an adequate amount. But I really hope that meat is not an essential cause of cancer because it will affect a lot of people if so.

Visit the following websites to get more detailed information:

• http://news.yahoo.com/s/nm/20071211/hl_nm/cancer_meat_dc_1
• http://medicine.plosjournals.org/perlserv/?request=get-document&%20doi=10.1371/journal.pmed.0040325

Genetic Face Lab

I was really curious at first. What does it mean by 'genetic face lab'? Does it have anything to do with my face?

Hehe.. actually, it has nothing to do with my face. Instead, the whole class had the opportunity to create a face by tossing a coin. Yes, a coin! There are two sides of a coin: head and tail, and we used these two sides of the coin to determine the characteristics of the face. It's kind of fun.

Want to see my work? It's up above. I know it's a bit... um... weird, but I think it's partly because I cannot draw well using the computer. Anyways, this lab helps me relax a lot and I enjoy the process of creating this strange face. By the way, do you have any idea if this is a boy or a girl?

Answer: Boy

Cooking with DNA: A Protein Synthesis Simulation

I love Rice Krispy Treat! It's great that the whole class could make Rice Krispy Treat in class and EAT it! Since the process of making Rice Krispy treats is analogous to the process of protein synthesis in cells, so making Rice Krispy can help all of us understand better about the protein synthesis process.

I was so happy that I was picked to be the group leader, which was actually the rRNA. I was supposed to direct and keep track of the whole thing. I also had to manage my group members(tRNAs), record the order in which they deliver their ingredients and instructions (amino acids), and coordinate the manufacturing of the protein.

My group was very effecient and cooperative. We were the fastest group to finish making the Rice Krispy treat and I don't think we made any mistake in the process of making it. It's really fun! I only ate a little piece of it and it tasted really good. Hope I will have a chance to COOK WITH DNA in the future!

News Article: Pollution-Busting Plants

Summary:

"A French hybrid of an aspen tree may one day rid water supplies of the industrial degreaser—and human carcinogen—trichloroethylene (TCE), one of the most common contaminants at toxic waste sites in the U.S. And the tiny, but tractable, plant Arabidopsis may mop up the residue of RDX, a military explosive blasted into the soils at firing ranges." said the article.

As we all know, plants are the Earth's good friends. They help to absorb carbon dioxide and, at the same time, give out oxygen by the process called photosynthesis. They improve the air quality and give people the impression of freshness.

Researchers are trying their best to make good use of plants. They tried to put a cytochrome (an enzyme) known as P450 2E1 into plants. They used a bacteria to insert the genetic code for this cytochrome isolated from rabbits into the genetic instructions of the hybrid aspen tree, which belongs to the poplar family.

The result turned out to be really amazing. The aspen sucked the contaminant out of the water much faster than unaltered aspen and removed a lot of it by the time they were done drinking the poison. It also boosted the tree's ability to absorb the chloroform left over after cleaning drinking water, the industrial solvent carbon tetrachloride and even vinyl chloride. They could also remove benzene, a known human carcinogen, 10 times faster than control plants.

Biologists working with the Arabidopsis plant, a flowering weed, successfully demonstrated that inserting a variant of cytochrome P450 isolated from battlefield bacteria allowed it to break down the RDX left behind in the soil of firing ranges. Such altered Arabidopsis, when drinking RDX-laced water, removed 90 to 97 percent of it.

The goal right now is to create trees that provide a low-cost option for cleaning contaminated groundwater and sites that might not otherwise be purified due to the expense of chemical and microbial treatments.

Reflections:

Right now, we are studying the topic of gene technology. We are learning about gene engineering. This article is somehow also related to transgene. Researchers inserted genetic code for cytochrome into the genetic instructions of the hybrid aspen tree. From this, we can see that gene engineering is really useful in our lives.

Gene technology benefits the environment, which in turn benefits us. According to the article, the genetically modified aspen proved capable of removing benzene, a human carcinogen, from air or trichloroethylene, the most common contaminant at U.S. toxic waste sites, from water while the Arabidopsis plant could break down the RDX left behind in the soil of firing ranges and removed 90 to 97 percent of RDX when drinking RDX-laced water. All these transgenic trees provide us with a cleaner and more comfortable environment.

The technology nowadays does make our lives much easier and more convenient. I really hope that more discoveries of gene technology can further improve our daily lives. The thing we can do is to treasure the plants and try to discover more wonderful things from them.

Want to know more about this article? Visit the following website:

http://www.sciam.com/article.cfm?articleID=A5B6ED51-E7F2-99DF-30AEE27247438296&chanID=sa022

DNA

On Monday, when the bell was about to ring, the whole class went out of the classroom to make DNA. What did we use to make DNA? Ourselves!!

We arranged ourselves in a straight line and tried to figure out the 5' and 3' ends. We used a bit of time to review what we have learned about DNA. DNA is made up of purines and pyrimidines. It starts from the 5' end and we always extend the 3' end. They are basic things. Since we have boys and girls in the class, it was easy to demonstrate the structure of DNA. Boys could act as purines while girls acted as pyrimidines. In this way, boys and girls always pair up with each other because purines and pyrimidines pair up with each other.

Later in this week, we went deeper into the structure and discovery of DNA. It was pretty difficult to imagine that the little DNA is the genetic material and thus so essential in our lives. On Friday, we also had the chance to construct a paper model of DNA, but I did not make one because I did not have time.

The next topic is gene technology. What other things will I discover in this chapter?

DNA Extraction

Before this lesson, I have never thought of extracting DNA. I thought that DNA could only be extracted by using complicated machines in hospitals. It kind of surprised me when I knew that I could actually extract DNA ourselves.

My group carefully followed the procedures on the guideline sheet. The DNA extraction procedures were pretty easy to follow. But I found that the materials used were quite weird. There were soap and alcohol. I had never dreamed of using soap to extract DNA. They didn't seem to have any relationship. I think I need to do more research to find out why soap is needed to extract DNA.

After several minutes, a white thing appeared between the soap and the water layers. I couldn't believe that it was the DNA. I couldn't really tell what it was like. Many groups also succeeded in extracting the DNA. I was really happy that everyone had a chance to extract and look at it.

I really enjoyed the whole process. But I hoped that I could have the opportunity to look at the DNA under the microscope. I would love to take a look at the inside of the DNA.

Active Transport

Now, don't make me get confused. Last time, I made it clear that I understood the meaning of passive transport. It does not require any energy. How come this active transport need energy to carry out movement?

Oh! Because active transport moves against the concentration gradient. If you think deeper, it is not that difficult to understand. We also need energy to fight against something. Examples of active tranport are sodium-potassium pump, movement in vesicles and membrane receptor proteins. The animation of sodium-potassium pump showed in class really illustrated clearly the movement of the pump. The powerpoint also helped a lot.

In my opinion, passive transport is easier to understand because the demonstration in class and the example of bouncing balls let me have the picture of what's going on. Overally speaking, this chapter is not very hard. I am looking forward to the next chapter - chromosomes.

Passive Transport

Passive transport is the movement of substances without using energy. Without energy? What does it mean? Doesn't everything need energy to move or function?

Ah...I see, diffusion! Diffusion means the net movement of substances from an area of higher concentration to an area of lower concentration. The substances are just like bouncing balls which keep bouncing forever. When they are put in one room with the door closed, they only bounce in that room. However, when the door is opened, the balls immediately go to the room with fewer balls because they do not need to squeeze with one another. They can have more space. This is an example of diffusion. And I now understand that the balls do not need energy to diffuse through the room.

Osmosis is also a type of passive transport. It is the diffusion of water through the cell membrane. As I indicated in the last sentence, the action is passive because osmosis is a kind of diffusion. Have problem understanding osmosis? No problem! The demonstration in class makes us all understand better. Some girls in class act as the cell membrane and some boys act as the water molecules. The boys move randomly around the girls, just like water molecules moving around the cell membrane. When Mr. Olson said 'stop', the number of boys on each side were always nearly the same. It shows that water molecules diffuse through the cell membrane until the state of equilibrium is reached. After that, Mr. Olson used chairs to represent salt. When he pulled out a chair, one boy would sit on it, just like water molecule attracting to salt. As chairs were pulled out on only one side of the cell membrane, there were fewer boys moving around on that side. Other boys then went to that side to fill in the space. As a result, there would be more water molecules on the side with salt.

This activity was really interesting and it let us move around during the lesson.

Wacky Properties of Water

Water, water, water!! I've never thought that the properties of water are so wacky. They are so amazing. Some of them really surprised me because I've never known it before. As biology class always leads us to a world of discoveries, I have found out a lot about water properties in this lesson.

The first thing we did today was to review the test we took last week. I was pretty satisfied with my score. The question that I got wrong was an analogy problem. Mr. Olson taught us how to solve these types of problems. I now know what these problems mean and could solve them by making a sentence using the two words given.

Later, we learned stuff about chemistry of cells. I know that besides water, I am also made of carbohydrates, lipids, proteins and nucleic acids. haha... I am made of so many things! In order to let us understand the four classes of organic compounds, Mr. Olson used the powerpoint while explaining.

As sitting on the chair was quite a boring thing, we were told to go to the lab stations to do simple experiments of water after the powerpoint. First, we had to place a drop of water at one end of the wax paper and tried to see how long it would take to get the whole water droplet to the other side. I only used four seconds to do so. That was pretty fast. Then, we had to repeat this thing by using glass slide instead of wax paper. And the result was really contrasting because the water on the glass slide could not be dragged on the glass slide. We finally concluded that water was both cohesive and adhesive. The glass slide is hydrophilic and the paper is hydrophobic. After that, we also did two more experiments. We found out something about capillary action from one of the experiments.

All these experiments are really intriguing. Through them, I can understand better about the WACKY properties of water.

Cohesion & Adhesion

Today in class, we didn't have much to do. We are now on a topic about water and solutions. Mr. Olson used the powerpoint and some animations to let us understand the things more. I understand most of them but I still get confused about the bonds sometimes.

The good thing was that we could do kind of an experiment after this powerpoint. We gonna dropped some water on a penny and also tried to put a paper clip on the water. We had to find out how many drops the penny could hold and also see if the paper clip would float on the water.

Before this little experiment, I guessed that the penny could hold ten drops of water. I thought I would guess wrong because most of the classmates guessed something about three drops. Oh! What a surprise! The penny could totally hold 25 drops. It really shocked me that the tiny little penny could hold such an amount of water. And when Mr. Olson came by my lab station, he used a normal finger and a soapy finger respectively to poke the water on the penny. It surprised me again when I saw that the water poked by the normal finger didn't have much difference while that poked by the soapy finger immediately broke apart. It was really amazing. Mr. Olson said that the reason for this was because of the surface tension on the water surface. Clearly, the soap broke the surface tension.

Well, for the paper clip, I was not successful to make it float on the water. But I was lucky to see one of my friends do it. I think I will try it again if I have the chance.

Time passed by really fast, I was in a hurry to pack away my things when the bell rang. But I was still in deep thought of the interesting experiment after class.

Snail Observation Lab

I was really excited when I knew that I was going to observe a snail in Biology lesson. I had never examined a snail before, so I was very happy when Mr. Olson told us that we were going to have a Snail Observation Lab.

We had to complete a set of questions for this snail observation. They included describing the snail, finding more about the snail's behaviour and its reactions to different substances. Besides observing, we also needed to find information in a reference book to answer the questions.

Although I was looking forward to the observation, I felt a little bit scared when I saw the snail. I tried to take it up and put it on the watching glass, but I was afraid that its shell would get off. Moreover, its slimy brown skin made me feel bad when I touched it. Finally, my partner and I removed it clumsily.

When we were observing the snail and writing down the answers, the snail kept crawling out of the watching glass and moved towards our paper. I nearly screamed out loud when it was on my paper.

We observed a lot of things from the snail. I had never noticed such things before, probably because I would not pick up a snail in a garden and observe it. I observed that the snail had tentacles and it had particular movements. It hates vinegar and opens its mouth when eating. I also got a lot of information from the reference book.

It was really fun to do all these observations. I really enjoyed that Biology lesson and I hope that I will have the opportunity to observe other things in the future.