Chapter 1 Review Questions
1. Can molecular biology be thought of as an extension of genetics. Please use
the definition of both fields as you explain your answer in depth.
2. Please define the term heredity. Who is considered the father of heredity?
Please state the laws of heredity the person discovered?
3. How did the definition of a gene change over time, starting in the early
1900’s.
4. Why are the roots of Molecular Biology found in Genetics? Please explain
your answer in detail.
5. Please state the three questions that the field of Molecular Biology tried to
answer as it grew out of Genetics? For each question, please state the answer
to each question and which experiment(s) were performed to answer each
question
6. Matching. Please match the scientist to his discovery/theory.
a. Aristotle
b. Mendel
c. Meischer
d. Weismann
e. Chargaff
f. Griffith
g. Alloway
h. Dawson
i. Hunt - Morgan
7. In the early 1900s, what two types of molecules were hypothesized to be
carriers of the information of heredity?
8. In the early 1900s, which molecule was thought to be the carrier of the
information of heredity? Please explain your answer in detail.
9. Today, which molecule is thought to be the carrier of the information of
heredity? Please explain an experiment that definitively proved this?
10. Please answer each question based on Griffith’s work.
For A-F please explain the result based on each of Griffith’s experiments.
A. Injecting live Type-R S. pneumoniae into mice.
B. Injecting live Type-S S. pneumoniae into mice
C. Injecting live Type-R S. pneumoniae mixed with heat killed Type-S S.
pneumoniae into mice
D. Injecting Type S S. pneumoniae mixed with heat killed type R S. pneumoniae
E. Sodium hydroxide degrades both nucleic acids and proteins. Injecting type
R S. pneumomiae with type S S.pneumoniae that was killed with NaOH.
F. Phenol denatures proteins, but does not affect nucleic acids. Injecting type
R S. pneumoniae with type S S. pneumoniae that had been phenol treated.
G. SDS is a detergent that kills and lyses cells, but leaves DNA intact. Injecting
type R S. pneumoniae with type S S. pneumoniae that is killed with SDS.
H. Injecting type R S. pneumoniae with type S S. pneumoniae that is killed with
SDS and then treated with heat above 100 C (Hint: think about DNA structure)
11. Please state the conclusion that Griffith’s reached based on his
experiments? Please explain in detail why he came to this conclusion.
12. Please explain how Lionel Alloway’s, and Henry Dawson’s work built upon
the work of Fredrick Griffith?
13. What is the true identity of the transforming principle? Please explain
how the identity of the transforming principle was discovered. Which
scientist(s) are given the most credit for discovering the identity?
14. Please explain the results based on the experiments performed below.
Please discuss the morphology of the Type R bacteria, as well as what happens
when the mix is injected into mice.
a. Take heat killed type S S. pneumoniae and treat with protease. Then, mix
with type R S. pneumoniae.
b. Take heat killed type S S. pneumoniae and treat with DNase. Then, mix with
type R S. pneumoniae.
c. Take heat killed type S. S. pneumoniae and treat with RNase. Then, mix with
type R S. pneumoniae.
d. Take heat killed type S. S. pneumoniae and treat with RNase and DNase.
Then mix with type R S. pneumoniae.
e. Take heat killed type S. S. pneumoniae and treat with Protease and DNase.
Then mix with type R S. pneumoniae.
f. Take heat killed type S. S. pneumoniae and treat with RNase and Protease.
Then mix with type R S. pneumoniae.
g. Take heat killed type S. S. pneumoniae and treat with Protease, RNase and
DNase. Then mix with type R S. pneumoniae.
15. What theory are Beadle and Tatum best known for? Is their theory still
correct today? Please explain.
16. Beadle and Tatum studied the pathway for Niacin synthesis. Niacin
synthesis starts with the amino acid tryptophan which is then converted to
kynurenine. The kenurenine is then converted to 3-hydroxyanthranillic acid.
The 3-hydroxyanthranillic acid is converted to niacin.
a. Below, please write out the pathway.
b. What did Beadle and Tatum do to their neuorspora to induce muations?
17. You have test tubes with minimal media supplemented with the following,
and are recreating the work of Beadle and Tatum.
i. tryptophan
ii. kynurenine
iii. 3-hydroxyanthranillic acid
iv. niacin
Please state which of these media the mutant spores below will grow on.
a. Spore that contains a mutation in the gene encoding the enzyme that
converts 3-hydroxyanthranillic acid to niacin
b. Spore that contains a mutation in the gene encoding the enzyme that
converts tryptophan to kynurenine.
c. Spore that contains a mutation in the gene encoding the enzyme that
converts kynurenine to 3-hydroxyanthranillic acid.
18. How were Hershey and Chase able to specifically follow DNA or protein in
their experiments? Please explain how this was possible.
19. How did Hershey and Chase label the different molecules they wished to
study? How does the label of these molecules relate to their chemistry?
20. How did Watson and Crick determine the secondary structure of DNA?
What type of structure did they find?
21. Please state three criteria the material of heredity must meet?
22. Please discuss the evolution of what the material of heredity encodes
starting with Beedle and Tatum.