Nucleic acid functions, chemistry, Microeconomics

Nucleic acids perform two important functions

1. Replication: It is the property of biomolecules to synthesise exact copy of it. DNA has this unique property of duplicating itself. The genetic information for the cell is coded in the form of the sequence of bases adenine (A), thymine (T), guanine (G) and cytosine (C) in the DNA molecules. During division of cell, DNA molecules replicate and produce exact copies of them. Each daughter cell has DNA molecules identical to that of the parent cell. According to a prominent theory of DNA replication, the two strands of DNA helix unwind and each strand serves as a template of pattern for the synthesis of a new strand in the cell environment. The specificity of base pairing ensures the exact duplication of sequence of bases in the reproduced strand of (DNA).

2. Protein synthesis: The DNA molecules in the cell nucleus hold the code for the protein synthesis. The genetic information is coded in DNA in the form of specific sequence of bases. The synthesis of a specific protein involves the following two steps:

Transcription involves copying of sequence of bases from the DNA strand on the RNA molecule called messenger RNA (mRNA). The bases of the mRNA are complementary to those of the DNA strand. Messenger RNA contains only four bases adenine (A), guanine (G), cytosine (C) and uracil (U). DNA molecules contain the four adenine (A), guanine (G), cytosine (C) and thymine (T). the complementary base pairs are as follows:

Adenine (A)
Guanine (G)
Cytosine (C)
Thymine (T)
Uracil (U)
Cytosine (C)
Guanine (G)
Adenine (A)

After transcription mRNA moves from the nucleus of the cell to a ribosome in the cytoplasm where it serves as template for the protein synthesis.

The sequence of bases in mRNA is read in a serial order in groups of three at a time. Each triplet of nucleotides (having a specific sequence of bases) is known as codon. Each codon specifies one amino acid. Many amino acids have more than one codons. The amino acids are brought to the mRNA by another type of RNA and called transfer RNA (tRNA). Each amino acid has at least one corresponding tRNA. At one end of the tRNA molecule is a trinucleotide base sequence that is complementary to some trinucleotide base sequence on mRNA (anticodon). The other end of tRNA molecule on mRNA is (anticodon). The other end of tRNA molecule carries a specific base sequence of three nucleotides carries a specific base sequence of three nucleotides - CCA - with a - OH group on the sugar exposed on the terminal adenine nucleotide (amino acid attachment site).

This - OH group combines with a specific amino acid and carries it to the mRNA. The complex between mRNA and tRNA is stabilized by another type of RNA called ribosome RNA (rRNA). After transfer of amino acid, the tRNA is free to go back and repeat the process. Thus, proteins with a specific sequence of amino acids are produced. The sequence of amino acids in proteins is determined by the sequence of nucleotide bases on mRNA which in turn is determined by the sequence of bases in DNA molecule. The DNA sequence that acts as a code for a specific protein is called gene. Every protein in the cell has a corresponding gene. The relationship between the nucleotide triplets and the amino acids is called genetic code.

The genetic code has four noteworthy features:

(i) It is universal.

(ii) It is degenerate. It means that more than one codons can act as a code for an amino acid. 

(iii) It is commaless.

(iv) The third base of the codon is less specific. The first two bases of the codon are most important.

Synthesis of proteins in the body takes place at very fast rate. Only minutes after the radioactive amino acids are injected into the animals, radioactive proteins can be found.  

Expertsmind offers unique solution for chemistry assignments

Posted Date: 2/15/2012 12:39:57 PM | Location : United States

Related Discussions:- Nucleic acid functions, chemistry, Assignment Help, Ask Question on Nucleic acid functions, chemistry, Get Answer, Expert's Help, Nucleic acid functions, chemistry Discussions

Write discussion on Nucleic acid functions, chemistry
Your posts are moderated
Related Questions
to what extent are interest rates determined by the economic theory

chemistry assignments ,  Some normally nonmagnetic substances are attracted by a magnetic field and studies of these "paramagnetic" substances give information about the number of

Labor Total Output 1 30 2 50 3 60 4 75 5 80 a) If the price of the firm’s output is $12 per unit and the wage rate is $100 per worker, how many workers should the firm choose to

Monopsony: Demonstrate (with a graph) how a minimum wage can increase both the wage and employment in a monopsony market even when the government sets th

is south african economic system more allocative efficient?

International Comparisons Method In the 1960s, a few developing countries of the world looked around the developed world in search of models of development. For instance, Sout

MRP systems - basic inputs  It has been estimated that in the USA where MRP was originated and developed by Oliver Wight and George Plossl (1985), virtually all Fortune 500 ma

Once countries already have a high level of production, how might they achieve living standards growth?  Once countries achieve a high level of production, they might be achiev

Mrs Holt, 85 years old, has been admitted to acute care following a fall resulting in a fractured femur. She is a widow and lives alone with her three cats for company. a) What

Consumers purchase a house or multiple dwellings for a number of reasons. But what is the rationale behind their decision to buy and/or sell a house, flat or apartment? Do consumer