MCB 3201 Sample Exam I
Part I: Define the following terms with simple sentences (30%).
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
Zwitterion:
Isoelectric point:
DNA ligase:
Southern blot hybridization:
Restriction enzyme polymorphism:
In situ hybridization:
Cloning vector
Dominate negative mutant
Cot analysis
Plasmid
Heterochromatin
Solitary gene
Nucleosome
Histone code
Sigma factor (70)
Homeotic mutation
Epigenetic change
Part II: Short essay questions.
1. Weak chemical bonds are essential for assembly of sapromacromolecules in the
biological system. Describe the importance of each weak chemical bond in the
assembly of sapramacromolecules in the biological system.
2. What are hydrophobic amino acids, basic amino acids, acidic amino acids and polar
amino acids? Discuss the contribution of each class of amino acids in the formation of
the secondary, tertiary and quaternary structures of proteins.
3. Use a few sentences to explain the involvement of the following listed items in cloning of
a DNA fragment.
a. restriction enzyme; b. T4 DNA ligase; c. plasmid cloning vector; d. colony
hybridization; e. E. coli cells.
4. What are the differences between a cDNA library and genomic library?
5. What is PCR technology? Describe briefly how this technique can be used to clone a
piece of genomic DNA molecule?
6. Discuss how a gene can be specifically knocked out in the muscle cells of a mouse.
7. Describe the three different ways that multiple mRNAs can arise from a complex
transcription unit in eukaryotes
1
8. Describes the differences between euchromatin and heterochromatin. What are the
relationships between post-translational modifications of histone tails and the chromatin
structures?
9. Histone tails of H2A, H2B, H3 and H4 are modified via post-translational modification.
Describe the types of histone tail modification and the contribution of the modification to
the structure of chromatin.
10. What types of changes in the chromatin structure will lead a cell to commit to a particular
differentiation pathway?
III. Problem Solving
1. Data of the hybridization kinetics (Cot analysis) of a hypothetical DNA sample are given in
the figure below.
Base on the data presented in the figure, please answer the following questions:
(a) How many classes of sequence complexity are there in this DNA molecule and identify the
Cot1/2 of each component.
(b) Please determine the sequence complexity of each component if the Cot1/2 of the E. coli
DNA determined under the same hybridization is 9.0 and its sequence complexity is 4.2 x
106 bp
2. DNase I is a useful enzyme to differentiate an active gene from an inactive gene. It also is
useful in identifying the site on the regulatory region of a gene that may interact with
regulatory proteins. Please design an experiment to demonstrate how DNase I is used to
differentiate an active/potentially active gene from an inactive gene.
.
2