Thursday, December 16, 2010

The Longest Prezi You Will See in Your Life

Well...this one's a biggie.

It's pretty self-explanatory, so I won't say much more.

However, I will point out that my energy and focus was gone by the time I got around to the Calvin Cycle, so if typos and mistakes abound...you know why.

Have fun!

Wednesday, December 15, 2010

The Joy of Making Bubbles with Enzymes

Well, we did a little experiment with enzymes to see just how they worked. Our setup was relatively simple: 3 mL of water and 3 mL of hydrogen peroxide. Our enzyme was simply yeast, and the object was to manipulate various variables with the reaction to see what the change would be. My attempt at explaining what was going on is that the yeast breaks off the oxygen from the hydrogen peroxide and releases the oxygen into the atmosphere. This created the pressure we measured with a pressure probe.

Here are the various graphs we managed to draw from the experiment. I'll explain the meaning of each as we go along. 


This graph shows the change in the rate of reaction as we changed the concentration of the enzyme. The slope of this graph is relatively constant, suggesting that the rate of reaction is directly related to the concentration of the enzyme.

This graph (although admittedly bizarre) shows the change of the rate of reaction as the pH level of the solution the reaction was occurring in changed. We used buffers to hold the pH at constant levels of 4, 7, and 10, and found that the highest rate of reaction was when the pH was the pH of water--7.

This graph shows the change of the rate of reaction as we changed the temperature of the solutions that the reaction was occurring in. We used four different temperatures, namely, 0, 25, 38, and 80 (all of which were measured in degrees Celsius). By looking at this graph, we can see that the greatest rate of reaction occurred at slightly warmer than room temperature, but that the enzymes' productivity fell dramatically as the heat increased too much. This was explained when we realized that the heat could cause the enzymes to become denatured (meaning that the shape changed).

Wednesday, December 8, 2010

Unpronouncable Words...And Lots of Them

As we've spent a large proportion of time recently discussing enzymes, I thought I'd put together a little post on a disorder of an enzyme: PKU. (I found most of this information in the Mayo Clinic article.)

Phenylketonuria (fen-ul-ke-toe-NU-re-uh) is a genetic defect that results in too much of the acid phenylalanine. It's caused by mutation within a gene that contains the instructions to make the enzyme that breaks it down. Amino acids are the fundamental building blocks of proteins, but too much of phenylalanine results in various health problems. People who have this excess of the phenylalanine, referred to as PKU, must carefully limit their diets so that they do not consume too much phenylalanine (which is found primarily in protein-rich foods).

At birth, babies within the U.S. and several other countries are screened for PKU. When it is caught soon after birth, serious complications can be prevented.
  
When a baby is born with PKU, he or she has no symptoms. Soon after, however, the various complications arise. These include:
  • Mental retardation
  • Behavioral or social problems
  • Seizures, tremors or jerking movements in the arms and legs)
  • Hyperactivity
  • Stunted growth
  • Skin rashes (eczema)
  • Small head size (microcephaly)
  • A musty odor in the child's breath, skin or urine, caused by too much phenylalanine in the body
  • Fair skin and blue eyes, because phenylalanine cannot transform into melanin — the pigment responsible for hair and skin tone
Let's go a little deeper with the causes of PKU:

PKU is caused by a genetic mutation. The gene that is defective is the one that carries the information used to make an enzyme that breaks down phenylalanine. Because this particular amino acid is allowed to flourish, a hazardous buildup of the acid can occur when a patient eats foods such as milk, cheese, nuts, or meats (foods that are rich in protein). This buildup leads to potentially serious health problems.

Because PKU is a genetic disease, the defective gene must be passed on to a child from both the mother and the father. This typically happens when the parents do not know that they have the defective gene. (Think of Typhoid Mary. People who have the defective gene but not PKU are known as carriers.)

Well, I think that's all for now! Who knows? I might actually stay on top of blog posts this time!

(Ha ha! How funny that is!) 

Poisonous Thoughts

Mustard gas. What is it really?

An article I found gave me a few answers. It's a poison that is particularly bad for the skin and the eyes, but can also affect the lungs and other organs if it is inhaled. Although it is typically not fatal, it does have severe effects. However, these effects do not occur immediately after exposure; rather, symptoms take up to six hours to develop. This can be a problem because permanent damage can occur before the victim even knows that they need medical treatment!

Mustard gas is a so-called "blister agent," meaning that it is a chemical that can damage the skin, eyes, and lungs. In comparison with "nerve agents," (chemicals that prevent the nervous system from properly functioning) it is not as likely to become fatal. However, the amount to which a victim is exposed plays a role in the long-term effects. Long-lasting complications (such as cancer) can be traced back to mustard gas.

Another article gave me some more in-depth information on the processes of mustard gas. As an alkylating agents, it binds to nucleophilic molecules (molecules that share electrons with another molecule to bind with them) such as both types of nucleic acids as well as proteins and various parts of cell membranes. Obviously, this can be bad. For example, when it bonds with DNA, it can cause the strands of DNA to break or develop various other problems. When mustard gas bonds with RNA, it can alter the creation of proteins that are dependent upon the RNA, which results in the death of the cell.  Because mustard gas also binds to some proteins, it can change the shape of those proteins, which can alter the enzyme activity. Finally, mustard gas can also alter the structural proteins of the membrane of the cell or cause the lipids within the cell to be damaged, both of which can cause the death of the cell.

Can anything be done for people who have been exposed to mustard gas? Unfortunately, the answer is "not too much." It seems that decontamination is the primary method of treatment for exposure to mustard gas. There is no antidote (at least at the time of publication of the latter article) and, although thiols have been suggested as possible treatment, there is not a wide acceptance of this method.

Photosynthetic Imagination

Well, after complaints from my audience (meaning: me) about the high concentration of prezis, I've reverted to Power Points. Here's a little thing I threw together about an imaginary experiment (literally, a thought experiment).

Embedding is not working well (read: not working at all) so, for now, I'll give you a link to the presentation. Hopefully, I can get it embedded sometime!
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