1. Previous scientific evidence is a catalyst for new scientific discoveries. How did Hershey and Chase demonstrate that DNA is the genetic material of viruses following the statement by R.M. Herriott (1951) that "A virus may act like a little hypodermic needle full of transforming principles"?
2. Complete the following table:
Enzyme Function in DNA replication
DNA polymerase III
Helicase
Primase
Gyrase
DNA polymerase I
DNA ligase
3. What is linkage? Do linked alleles normally assort independently?
4. Outline the process of transcription. You may use a diagram to illustrate your description. With regards to RNA polymerase, how does transcription differ between prokaryotes and eukaryotes?
5. What three modifications does eukaryotic mRNA receive during processing? What is the name of the molecular complex that carries out splicing?
6. For each of the following statements, indicate which of the following descriptions apply. Note: The descriptions may apply to more than one of these gene types.
OG: oncogene
PO: proto-oncogene
TS: tumour-suppressor gene
____ a. found in normal cells
____ b. could code for a normal growth factor
____ c. found in cancer cells
____ d. found only in cancer cells
____ e. its presence can cause cancer
____ f. its absence can cause cancer
____ g. can be found in both normal cells and cancer cells
7. Tetracycline is an effective antibiotic because it inhibits protein synthesis. The action mechanism is binding the 30s ribosomal subunit in bacteria, thereby preventing the docking of amino-acylated tRNA. With your knowledge of the translation process, explain how tetracycline would prevent protein synthesis.
8. Outline how proteins are targeted to the mitochondria and chloroplasts. Since mitochondria and chloroplasts contain their own DNA and protein-synthesis machinery, why must proteins be sorted to these organelles?
9. Outline all of the elements of the lac operon, and describe how the operon reacts to increases and decreases in lactose concentration.
10. Discuss the role of alternative splicing as a mechanism of post-transcriptional control. How does alternative splicing contribute to diversity? What factors influence how splicing patterns are determined?
11. The drug colchicine was formerly used to treat gout. Now, other drugs with a similar function are being considered for the treatment of cancer. What cytoskeletal component do colchicines affect, and why would drugs that target this component be effective at treating cancer?
12. Outline the process of muscle contraction.
13. Read the following article and answer the questions below. A new molecule of life?
a. What is a PNA? Describe the chemical composition of a PNA. How does a PNA bind to DNA and RNA?
b. Considering the composition of a PNA, what advantages do these molecules have over antisense DNA and RNA molecules?
c. Outline in detail how a PNA regulates the expression of a gene.
d. Give an example of how a PNA can be used to treat a medical condition.
e. Explain how PNAs may be used to construct artificial life forms.