1. Read the following article and answer the questions below. This article can b
ID: 282623 • Letter: 1
Question
1. Read the following article and answer the questions below. This article can be found via the online journal databases in the AU Library at:
http://nsaapbiology.weebly.com/uploads/4/9/3/1/4931695/2012-10-03_pna_a_new_molecule_of_life.pdf (Copy this link)
Nielsen, P. (2008). A new molecule of life? Scientific American, 299(6), 64-71.
a) What is a PNA? Describe the chemical composition of a PNA. How does a PNA bind to DNA and RNA? (6 marks)
b) Considering the composition of a PNA, what advantages do these molecules have over antisense DNA and RNA molecules? (3 marks)
c) Outline in detail how a PNA regulates the expression of a gene. (5 marks)
d) Give an example of how a PNA can be used to treat a medical condition.
(3 marks)
e) Explain how PNAs may be used to construct artificial life forms.
(3 marks)
Explanation / Answer
A) PNA stands for peptide nucleic acids. They contain pseudopeptide skeleton as their backbone that replace the sugar phosphate backbone of DNA and RNA. They bind to the DNA using both Watson and Crick base pairing mechanism as well as Hoogsteen pairing.
B) The advantages of PNA over antisense DNA and RNA are the following,
C) PNA can regulate gene expression by regulating transcription and blocking translation. PNA can inhibit the activity of enzyme RNA polymerase involved 8n transcription. Triplex invasion by PNA also alters transcription. PNA interferes in translation process also by binding with the messenger RNA.
D) PNA can be used in the treatment of various carcinomas because of its ability to block transcription and translation thereby blocking uncontrolled proliferation of tumor cells.
E) PNAs may be used both as a storehouse of genetic information like DNA as well as catalytic machinery of an artificial cell.
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