Inquiry in the Natural World
– Spring 2003
Student Topic Guide #10:
Inheritance
Topic
objectives:
1. Know what factors
contributed to the success of Mendel’s investigations of
inheritance.
2. Understand how Mendel’s
hypothesis explains why children don’t always resemble either of their parents,
and how traits can skip a generation.
3. Be able to describe how
scientists came to the conclusion that genes are on
chromosomes.
4. Know how the work of (a)
Avery, Macleod and McCarthy; (b) Chargaff; and (c) Franklin contributed to
Watson and Crick’s development of a model for the structure of
DNA.
5. Know the structure of DNA,
including the basic structure of nucleotide building blocks, how nucleotides are
linked to form DNA strands, and how bases pair in the DNA double
helix.
6. Be able to explain how DNA is replicated, how the information in DNA is “transcribed” to make messenger RNA, and how the information in messenger RNA is “translated” into the amino acid sequence of a protein.
7. Be able to describe some of the ways that the scientific method, and other considerations, influenced Watson and Crick’s work on the structure and function of DNA.
Day 2 (Monday, 31
March):
Reading assignment:
Trefil and Hazen. 2001. The Sciences, 3rd edition. Chapter 23
Learning
Exercises:
1. Explain how each of the
following factors contributed to the success of Mendel’s
experiments:
Use of an organism
with several easy-to-distinguish traits
Use of pure-breeding
stocks as the parental (P) generation
Continuance of
experiments for at least two generations (F1 and F2
generations)
Quantitative analysis
of results
Ability to formulate a
testable hypothesis
2. Briefly explain how
Mendel’s hypothetical genetic “elements” (now called “genes”) later came to be
identified with (A) the nucleus; and then (B) chromosomes; and then (C) DNA
molecules
Day 3 (Wednesday, 2
April):
Readings (all from the 17
Feb 2003 issue of Time
magazine):
Lemonick, M.D. “A twist of
fate”
Lemonick, M.D. “You have to
be obsessed”
Golden, F. “Beyond the
double helix”
Grossman, L. “Mystery
woman”
Learning exercises:
1. A. Fill in the blanks in the
exercise on mechanisms of replication, transcription and translation on the back
of this page. B. Identify
and explain three interesting possible consequences of a “point mutation” (= a
change in one base) in the “original” DNA strand that serves as the template for
the mRNA?
2. Based on the Time
magazine readings concerning the discovery of the structure of DNA... A.
identify a hypothesis that proved false, and describe how the investigators
responded; B. identify two examples of preconceptions entering the
process; C. describe the roles of arrogance and obsession; D.
describe the importance of scientific meetings; and E. identify two
things that scientists do besides “investigate” that contribute to the progress
of science.
(NB: The
first tRNA should correspond to the first “start” codon in the mRNA)
Complementary
DNA:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Original DNA:
G T C A T A C G C A C T C G T G T T C A T C G G T
(template
for
mRNA)
Messenger RNA: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
_ _ _ _ _
(mRNA;
codons)
Transfer RNA’s:_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
_ _ _ _ _ _
(tRNA’s;
anti-codons)
Amino
acids:
(use “genetic code”
table
in text – p.
520)