Dr. Stuart Reichler Bio 325

DateSubject Sept 6Introduction, Philosophy of Science, and Strong Inference 11DNA and Gene Structure 13Signal Transduction 18, 20, 25Transcription and Translation (Homework #1 due 9/20) Sept 27Exam 1 Oct 2Gene Expression in Bacteria and Viruses 4, 9, 11Gene Expression in Eukaryotes and Development 16Genome Organization 18, 23, 25Biotechnology Oct 30Exam 2 Nov 1Mitosis and the Cell Cycle 6, 8Mutations and Cancer 13Meiosis and Developing Genetic Diversity 15, 20Inheritance Nov 22Thanksgiving (no class) 27, 29Inheritance Dec 4Evolution Dec 6Exam 3 Dec 8Final Exam 9am-noon

Q: Why does DNA have a very regular 3- dimensional shape while RNA has a varied 3-D shape?

A: RNA is single-stranded so areas with complementary bases form loops and bend the RNA. DNA is double stranded, and the regularity of its structure only allows one 3- D structure, a double helix.

Q: Describe two problems that would prevent a human gene from being properly expressed in bacteria.

A: Eukaryotic promoters do not work in bacteria, eukaryotic promoters need transcription factors. Eukaryotic genes typically have introns, and bacteria cannot splice out introns.

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.

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.

The Question: 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.

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

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)