Download 9/6 - bio.utexas.edu

Dr. Stuart Reichler
Bio 325
Date
Subject
Sept 6
Introduction, Philosophy of Science, and Strong Inference
11
DNA and Gene Structure
13
Signal Transduction
18, 20, 25
Transcription and Translation (Homework #1 due 9/20)
Sept 27
Exam 1
Oct 2
Gene Expression in Bacteria and Viruses
4, 9, 11
Gene Expression in Eukaryotes and Development
16
Genome Organization
18, 23, 25
Biotechnology
Oct 30
Exam 2
Nov 1
Mitosis and the Cell Cycle
6, 8
Mutations and Cancer
13
Meiosis and Developing Genetic Diversity
15, 20
Inheritance
Nov 22
Thanksgiving (no class)
27, 29
Inheritance
Dec 4
Evolution
Dec 6
Exam 3
Dec 8
Final Exam 9am-noon
Q: Why does DNA have a very regular 3dimensional shape while RNA has a
varied 3-D shape?
Q: Why does DNA have a very regular 3dimensional 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 3D structure, a double helix.
Q: Describe two problems that would
prevent a human gene from being
properly expressed in bacteria.
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
What is the major difference between these two
approaches to science?
Johann Baptista van Helmont
Aristotle (~2,300 y.a.):
Plants gain mass by taking it in 1600’s
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.
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)
Prion
Propogation
Interaction
between prion
and normal
protein causes
normal protein
to misfold…
… which leads to
increasing numbers
of prions
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)