In DNA, the two strands being complementary, if separated (denatured) by heating can come together (renaturation) when appropriate condition is provided. Further, 2' OH group present at every nucleotide in RNA is a reactive group that makes RNA liable and easily degradable. RNA is also known to be catalytic and reactive. Hence, DNA is chemically more stable and chemically less reactive when compared to RNA. Presence of thymine instead of uracil in DNA confers additional stability to DNA.

In some retroviruses that contain RNA as the genetic material (e.g. HIV), the flow of information is reversed. RNA synthesizes DNA by reverse transcription, then transcribed into mRNA by transcription and then into proteins by translation. This is called reverse transcription.

In the complete absence of lac operon permease will not be synthesized which is essential for transport of lactose from the medium into the cells, then it cannot act as an inducer. Hence, cannot relieve the lac operon from its repressed state.

Structural difference between DNA and RNA.

Human genome project was considered to be a mega project because
1. It had a specific goal to sequence for everybase pair present in the human genome. (Human Genome has 3.1647 billion nucleotide base pairs).
2. It took around 13 years of completion and got accomplished in year 2006.
3. It was a large-scale project, which aimed at developing new technology and generating new information in the field of genomic studies.
4. As a result of it, several news areas and avenues have opened up in the field of genetics, biotechnology and medical sciences.
5. It provided clues regarding the understanding of human biology.

(i) AAU - UUA
(ii) CGA - GCU
(iii) UAU - AUA
(iv) GCA - CGU

tRNA on one hand binds to specific amino acids and on the other hand reads the codon of the amino acid bound to it through its anticodon, it is called as adapter molecule.

They inferred each strand of the double strands helps was used as a template for the formation of a new, daughter strand having a complementary sequence of bases.