Dr. Stuart Reichler Bio 325

Sample Exam Questions: Some organisms have much more DNA than humans do. Does this mean that they can make a greater diversity of proteins than humans can? Why or why not?

Sample Exam Questions: Some organisms have much more DNA than humans do. Does this mean that they can make a greater diversity of proteins than humans can? Why or why not? Not necessarily. They may have more non- coding DNA.

Sample Exam Questions: If a transposon was inserted into an intron, would the gene product still be properly produced? Why or why not?

Sample Exam Questions: If a transposon was inserted into an intron, would the gene product still be properly produced? Why or why not? Either: Yes, the intron will be spliced out along with the transposon thereby having no effect on the final mRNA. No, the transposon will disrupt proper splicing of the intron thereby causing the mRNA to have additional and improper sequence.

Sample Exam Questions: What is a major weakness of the data obtained via microarray analysis?

Sample Exam Questions: What is a major weakness of the data obtained via microarray analysis? Microarrays show differences in mRNA levels, but that does not necessarily correlate to changes in protein levels.

Studying Biology: Start with a question. –For example: How? Why? When? Where? Etc? How do we get answers? –Strong Inference presents one method (article on webpage)

Cause of Peptic Ulcers: Overabundance of stomach acid due to Stress Diet Anxiety

Cause of Peptic Ulcers: Overabundance of stomach acid due to Stress Diet Anxiety Treatment: Antiacid U.S. bought $4.4 billion in 1992 Tranquilizers

Dr. Barry Marshall

The real cause of 80% of ulcers… H. pylori

Strong Inference Knowledge is gained by eliminating incorrect ideas. Disproof is more reliable than proof.

Where does the matter come from for plants to grow? Matter can not normally be created or destroyed, only moved from one place to another.

Aristotle (~2,300 y.a.) : Plants gain mass by taking it from the soil. Supporting Evidence: Plants need soil to grow. If roots are removed, plants die. After several years of cultivation, soil loses its ability to support plant growth.

Johann Baptista van Helmont did a simple experiment in the early 1600’s

Johann Baptista van Helmont in 1600’s Supporting Evidence: Plants need soil to grow. If roots are removed, plants die. After several years of cultivation, soil loses its ability to support plant growth. Aristotle (~2,300 y.a.): Plants gain mass by taking it from the soil… What is the major difference between these two approaches to science?

The Rules of Strong Inference: Strong Inference is a method for looking at scientific problems by trying to disprove hypotheses and accepting the hypotheses that can not be disproved. Using Strong Inference entails following these rules (from an article by John Platt, 1964): 1. Devise multiple hypotheses.

The Rules of Strong Inference: Strong Inference is a method for looking at scientific problems by trying to disprove hypotheses and accepting the hypotheses that can not be disproved. Using Strong Inference entails following these rules (from an article by John Platt, 1964): 1. Devise multiple hypotheses. 2. Design experiment(s) to eliminate one or more of the hypotheses.

The Rules of Strong Inference: Strong Inference is a method for looking at scientific problems by trying to disprove hypotheses and accepting the hypotheses that can not be disproved. Using Strong Inference entails following these rules (from an article by John Platt, 1964): 1. Devise multiple hypotheses. 2. Design experiment(s) to eliminate one or more of the hypotheses. 3. Carry out the experiments in a manner that gives a clean result.

Johann Baptista van Helmont did a simple experiment in the early 1600’s What experimental errors might this experiment have?

The Rules of Strong Inference: Strong Inference is a method for looking at scientific problems by trying to disprove hypotheses and accepting the hypotheses that can not be disproved. Using Strong Inference entails following these rules (from an article by John Platt, 1964): 1. Devise multiple hypotheses. 2. Design experiment(s) to eliminate one or more of the hypotheses. 3. Carry out the experiments in a manner that gives a clean result. 4. Repeat. Refine hypotheses.

The Rules of Strong Inference: Strong Inference is a method for looking at scientific problems by trying to disprove hypotheses and accepting the hypotheses that can not be disproved. Using Strong Inference entails following these rules (from an article by John Platt, 1964): 1. Devise multiple hypotheses. 2. Design experiment(s) to eliminate one or more of the hypotheses. 3. Carry out the experiments in a manner that gives a clean result. 4. Repeat. Refine hypotheses.

Are conclusions presented likely to be correct? …the Questions: Can your hypothesis be disproved? What experiment(s) can disprove your hypothesis?

The Rules of Strong Inference: Strong Inference is a method for looking at scientific problems by trying to disprove hypotheses and accepting the hypotheses that can not be disproved. Using Strong Inference entails following these rules (from an article by John Platt, 1964): 1. Devise multiple hypotheses. 2. Design experiment(s) to eliminate one or more of the hypotheses. 3. Carry out the experiments in a manner that gives a clean result. 4. Repeat. Refine hypotheses.

What causes Mad Cow Disease (aka BSE)?

Brain tissue from cow with BSE. Scrapie in sheep, CJD or Kuru in humans looks similar.

Is Mad Cow Disease (BSE) transmissible?

How could you test for the infectious agent?

Dr. Stanley Prusiner was awarded the Nobel Prize in 1997 for the discovery of prions… infectious proteins.

normally folded proteins Prion (abnormally folded protein) Interaction between prion and normal protein causes normal protein to misfold… … which leads to increasing numbers of prions Prion Propogation

Scientists communicate by publishing their findings in journals…