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Science!!!!! :)

Sunday, March 25, 2012

Science Gone Bad

          In 1939, Doctor Wendell Johnson decided to conduct an experiment on 22 orphans - ten of whom stuttered when they talked, and the rest with no speech impairments.  He divided up the ones that stuttered into two groups - one group that got negative reinforcement, and the other got positive reinforcement.  He also divided the children that spoke normally into two groups - one that was told they had good speech, and another that was told that they stuttered and that they needed to look out for errors all the time.  He wanted to make the group of stutterers with positive reinforcement stop stuttering and the group of children who were told they stuttered to stutter.  The children who were told that they had speech problems immediately began to think that they could not speak well, and many stopped talking completely.  After the experiment, they were told three times that they had no speech problems, but it did not work.  Even when they had grown up, although none of the children who had been experimented on stuttered, many had speech impairments and were reluctant to talk. 
          I think that this experiment was inhumane and that the doctor never should have gone through with it.

Resources:  http://www.neatorama.com/2011/03/23/5-science-experiments-gone-wrong/

Sunday, March 11, 2012

Current Events: Brain Parasite affects Dopamine Levels in Brain

          New studies show that a parasite called Toxoplasmosis gondii that directly affects how much dopamine there is in the human brain.  It is transmitted to humans through cat faeces that ends up on the fruits and vegetables we eat.  The parasite gets to our brain, where it then infects it by making a cyst in it cells and creating an enzyme called tyrosine hydroxylase, which is a chemical used by our bodies to make dopamine.  Because of this, a carrier of toxoplasmosis gondii can have very high levels of dopamine.  These discoveries may help scientists explain or find cures for dopamine-related disorders such as schizofrenia or Parkinson's disease.  It is estimated that around 22% of Americans have the parasite in their bodies, and most of them live normally.  However, the parasite can be dangerous to those not immune to its affects - especially pregnant women. 

Resources: http://www.sciencedaily.com/releases/2011/11/111104102125.htm

Wednesday, March 7, 2012

Onion Mitosis Lab

Guiding Question:  Approximately how much time do cells spend in each phase of the cell cycle?
Cells spend approximately 56% of their time in interphase, about 28% of their time in prophase, 8%  of their time in metaphase, 5% in anaphase, and 3% of their time in telophase.  We figured this out by analyzing how many out of 36 cells were going through which phases of mitosis.  20/36 were going through interphase, 10/36 through prophase, 3/36 through metaphase, 2/36 through anaphase, and 1/36 through telophase.  We then turned those fractions into percents. 

Procedure:
Perform the onion root tip simulation and tabulate the number of cells in each phase. Construct an appropriate graph using your data to present the relative time a cell spends in each phase of the cell cycle.

Table:   
This graph shows the number of cells going through each phase of mitosis, and the approximate percentage of the time they spend going through them. 

Graphs:
These graphs are analyses of our tables.  They both show how much time a cell spends on each phase of mitosis.  The pie chart shows this in contrast to the whole time spent going through mitosis, whereas the bar graphs shows this in comparison to each phase. 
















Conclusion:
In conclusion, we can tell that the interphase part of mitosis is the longest part of the process that a cell devotes its time to.  Second comes prophase, then metophase, and after that anaphase and telophase.  Notice that as the mitosis process progresses, each phase takes a shorter and shorter period of time.  This, however, may not be completely reliable, since the onion-root biology website may not be correct.  With this in mind, I looked up the stages of mitosis over the internet, and the data we received from the onion website appear to be correct.