Question

Sort the following structures in order decreasing complexity

Nucleotide

DNA polymerase

Adenine

Y Chromosome

Human Genome

Nitrogen

Neutron

Answer 1

Ans)    Human Genome<Y chromosome <DNA polymerase < Nucleotide <Adenine< Nitrogen < Neutron

1. Neutron: it is subatomic particle located in the nucleus of an atom. In 1932 James Chadwick discovered the neutron and it does not have any charge but posses slightly more mass than the proton.

2. Nitrogen: in the 1772 Daniel Rutherford discovered the nitrogen. The atomic number of Nitrogen is 7 and mass is 14.00 and it belongs to the p-block of the periodic table. Earth atmosphere has 78.9% of nitrogen and at normal temperatures, it exists in gaseous form.

3. Adenine: it is purine nitrogenous base with two rings and found in both DNA and RNA. In DNA it is pair with Thymine by two hydrogen bonds but in RNA it pairs with the Uracil. When adenine pair with the ribose it forms adenosine and if it associated with the deoxyribose then it is deoxyadenosine. Adenine is important component of ATP and NAD

4. Nucleotide: it is a basic monomeric unit of DNA and RNA. Each monomeric nucleotide attached by phosphodiester bond form polynucleotide chain. Each nucleotide made up of a nitrogenous base, deoxyribose and phosphate moiety in DNA. DNA has dATP, dGTP.dCTP, dTTP nucleotides, but RNA has dATP, dGTP.dCTP, dUTP nucleotides.

5. DNA polymerase: it is an enzyme involved in the replication of DNA and it adds the dNTPs to the 3' hydroxyl group of RNA primer during the DNA replication. The DNA polymerase I was a first known polymerase discovered in 1956 by Arthur Kornberg in E.coli. It is coded by the polA gene and made up of 928 amino acids. It has a 5' to 3' polymerase activity which extends the 3' hydroxyl group of RNA primer, 3' to 5' exonuclease activity which involved in proofreading and a 5'to 3' exonuclease activity which mediate the DNA repair and nick translation. Till date in E.coli 5 different types of RNA polymerases are discovered.

6. Y chromosome: it is a sex chromosome found in males and contains 59 million base pairs (2% of the whole genome). It was discovered in 1905 by the Nettie Stevens in mealworm. SRY gene of Y chromosome triggers the development of testis.

7. Human Genome: all the nucleic acid sequences (DNA) in 23 chromosomal pairs of human constitutes the human genome. The protein-coding regions of DNA are called exons and non-protein coding regions of DNA is called introns. The amount of genome present in the haploid cell such as egg or sperm is three billion base pairs. The first draft of human genome completed in February 2001.