Bacteria are prokaryotic in nature, in which typical chromosomes are lacking. DNA is circular and naked as it is not surrounded by histones (basic proteins which are responsible for coiled structure of nucleosome).

Lac is obtained fom Laccifer or Kerria lacca or lac insect that belongs to Phylum- Arthropoda.

tRNA has four recognition sites among these one is the amino acid attachment site. It has the amino acid attachment site with the 3' terminal - CCA sequence.

The enzyme needed for replication of DNA i.e. formation of DNA from DNA is DNA polymerase III. DNA replication is initiated by RNA primer which is later removed by DNA polymerase I.

DNA replication is the process by which DNA makes a copy of itself during cell division. It takes place discontinuously. This process consists of 4 main steps:

1. Replication Fork formation
2. Primer binding
3. Elongation
4. Termination

Okazaki fragments are short sequences of DNA nucleotides which are synthesized discontinuously. One strand may synthesize a continuous strand. Both new strands are synthesized in 5' $\to$3' direction. Thus one strand is synthesized forwards and the other backwards.

Gene mutation or point mutation is the result of a change in the nucleotide sequence of the DNA molecule in a particular region of the chromosome. It occurs in the form of duplication, insertion, deletion, inversion or substitution of bases. Frame- shift mutation is the addition or deletion of a base that may change the reading frame of nucleotide sequence. 

Base pair substitution is a type of mutation involving replacement or substitution of a single nucleotide base with another in DNA or RNA molecule.

Gene pool is the total gene present in a population. Genome is the total genetic constitution of an organism. Codon is the basic unit of genetic code, a sequence of three adjacent nucleotide in DNA or mRNA that code for an amino acid. Gene is the basic unit of heredity; a sequence of DNA nucleotide that encodes a protein.

Cistron is a segment of DNA nucleotides that codes for a polypeptide chain. Triplet is a three nucleotides sequence coding for an amino acid.

Therefore, codon $\approx$ triplet
                cistron $\approx$ gene
DNA fingerprinting is technically called DNA profiling or DNA typing.

Split genes were discovered by Phillip Sharp and Robert Richard. The part of DNA which express itself by making mRNA is called exon. One exon is separated from others by inactive part of DNA called intron. This is called split DNA.

UGU codes for the same information as UGC as both code for cystine. UGA and UAG are nonsense codons and UGG codes for tryptophan.