Some major goals of HGP are to:
(i) Identify all the genes (approximately 20,000-25,000) in human DNA.
(ii) Determine the sequences of the three billion base pairs present in human DNA.
(iii) Store this information in databases.
(iv) Improve the tools for data analysis.
(v) Transfer the technologies to other sectors (like industries).
(vI) Address the ethical, legal and social issues (ELSI), that may arise from this project.

All the genes controlling a metabolic  pathway, constitute an operon,
e.g. lac operon trp operon
val operon his operon.

(a) (i) Amino acylation of tRNA or charging of tRNA
(ii) mRNA codon-AUG tRNA anticodon-UAC
(b) The part of the chromatin that is densely packed and stains dark, is called heterochromatin.

(i) It is attached at the 3' end of tRNA.
(ii) UUU and UUc.
(iii) Aminoacyl-tRNA synthetase.

(a) (i) Methionine.
(ii) Phenylalanine.
(iii) It is a termination codon that does not code for any amino acid.
(b) AUG - TAC,UUU - AAA and UAG- ATC.

(a) Sixty-one codons code for amino acids.
(b) Twenty amino acids are coded.
(c) Termination codons or non-sense codons.

In eukaryotes, there are three RNApolymerases.
(i) RNA-polymerase I catalyses transcription of rRNAs (28 S, 18 Sand 5.8 S).
(ii) RNA- polymerase II catalyses transcription of precursor of mRNA; it is called hnRNA.
(iii) RNA- polymerase III catalyses tRNA, 5srRNA and snRNAs.

1. Central Dogma of molecular biology
2. It is the present day representation of the central dogma of molecular biology.
3. RNA is made from DNA by the process of transcription.
4. With the discovery of retroviruses, there is reverse transcription, i.e. the synthesis of DNA on RNA template, catalysed by the enzyme reverse transcriptase
5. RNA is translated into a polypeptide, making use of amino acids, ribosomes and enzymes.

(i) The split-gene arrangement in eukaryotes represents probably an ancient feature of the genome
(ii) The presence of introns is reminiscent of antiquity.
(iii) The process of splicing represents the dominance of RNA-world.

(a)

(b) Non-histone chromosomal proteins are involved in the packaging of chromatin fibres at the higher levels.

1. R-cells are those cells that form rough colonies, without a capsule and are non-virulent.
2. S-cells are those cells that form smooth colonies, protected by a capsule and, are virulent.
He showed that DNA is the transforming principle.

The lac operon consists of
(i) three structural genes (z,y and a) which code for \(\beta \) -galactosidase, permease and transacetylase, respectively.
(ii) an operator; which controls the structural genes as a unit.
(iii) a regulatory gene ti.e., inhibitor gene) and
(iv) a promoter, where the RNA polymerase binds for transcription.
The regulatory gene codes for the repressor protein, all the time (constitutively): the repressor binds to the operator to inactivate the operon.
 Lactose enters the cell with the help of permease and the active form of lactose binds to the repressor and prevents it from binding to the operator.
This allows RNA polymerase an access to the promoter and transcription continues, i.e. lac operon is activated.