Here students can locate TS Inter 2nd Year Botany Notes Unit 4 Molecular Biology to prepare for their exam.
TS Inter 2nd Year Botany Notes Unit 4 Molecular Biology
→ Deoxyribon ucleic acid (DNA) and ribonucleic acid (RNA) are the two types ofn ucleic acids found in living systems.
→ Nucleic acids are long polymers of nucleotides.
→ In 1953, Watson and Crick, based on the X-ray diffraction proposed a very simple but i famous Double Helix model for the structure of DNA.
→ RNA was the first to evolve and DNA was derived from RNA.
→ Francis Crick proposed the Central dogma in molecular biology, which states that the genetic information flows from DNA → RNA → Protein.
→ DNA replicates semi conservatively, the process is guided by the complementary H-bonding.
→ The proof that DNA is the genetic material came from the experiments of Alfred Hershey and Martha Chase.
→ The process ofcopying genetic information from one strand ofDNA into RNA is termed as transcription.
→ The gene is defined as the functional unit of inheritance.
→ The DNA sequence coding for tRNA or rRNA molecule also define a gene.
→ Cistron is defined as a segment of DNA coding for a polypeptide.
→ In bacteria, the transcribed mRNA is functional hence can be directly translated
→ In eukaryotes, the gene is split
→ The coding sequences exons, are interrupted by non-coding sequences called introns.
→ Introns are removed and exons are joined to produce functional RNA by a process called splicing.
→ In capping an unusual nucleotide is added to the 5′ end ofhn RNA.
→ In tailing, adenylate residues are added at 3′- end in a template independent manner.
→ Genetic code is that which direct the sequence of amino acids during synthesis of proteins.
→ The codon is triplet 61 codons code for amino acids and 3 codons do not code for any amino acids, hence they function as stop codons.
→ The relationships between genes and DNA are best understood by mutation studies.
→ Regulation of transcription is the primary step for regulation of gene expression.
→ In bacteria more than one gene is arranged together and regulated in units called operons.
→ Lac operon is the prototype operon in bacteria, which codes fongenes responsible for metabolism of lactose.
→ The operon is regulated by the amount of lactose in the medium where the bacteria are grown. Therefore, this regulation can also be viewed as regulation of enzyme I synthesis by its substrate.
→ James Dewey Watson
- Born: James Dewey Watson April 6, 1928 (Chicago, Illinois, U.S.)
- Nationality: American
- Fields: Genetics
- Institutions:
- Indiana University
- Cold Spring Harbor Laboratory
- Harvard University
- University of Cambridge
- National Institute of Health
- Alma mater:
- University of Chicago
- Indiana University
- Thesis:
- The Biological Properties of XRay
- Inactivated Bacteriophage (1951)
- Doctoral advisor: Salvador Luna
- Doctoral students: Mario Capecchi
- Other notable students: Ewan Bimey
- Known for: DNA structure
- Molecular biology
- Notable awards: Nobel Prize for Physiology or Medione(1962), Copley Medal (1993)
- spouse: Elizabeth Watson (née Lewis)
→ Francis Crick:
- Born: Franas Harry Compton Crick 8 June 1916 Weston Favell, Northam ptonshire, England, UK
- Died: 28 July 2004 (age 88) San Diego, Cahfornia, US. Cdori oenoer
- Residence: UK, US.
- Nationality: British
- Fields: Physics, Molecular biology
- Institutions:
- University of Cambridge
- University College London
- Salk Institute for Biological Studies
- Alma mater: University College London (BSC) Gonville and Calus College, Cambridge (PhD)
- Thesis: Polypeptides and Proteins : X-ray studies (1954)
- Doctoral advisor: Max Perutz
- Known for: DNA structure consciousness
- Notable awards: Nobel Prize (1962)
→ In 1962 James Watson and Francis Crick jointly received the Nobel Prize in Physiology or Medicine for their determination of the structure of deoxyribonucleic acid (DNA)
- They both were also honoured by the John Collins Warren Prize of the Massachusetts General Hospital in 1959, the Lasker Award in 1960, the Research Corporation Prize in 1962.
- James Dewey Watson was born in Chicago on 6 April 1928. In 1951, 23 year old James Watson a Chicago – born American, arrived at the Cavendish Laboratory in Cambridge. Watson had two degrees in Zoology, a bachelor’s degree from the University of Chicago and a doctorate from the University of Indiana where he became interested in genetics his doctorate degree in 1950 was on the study of effect of hard x -rays on bacteriophage multiplication.
- Francis Harry Compton Crick was born on 8 June 1916 at Northampton, England. He studied physics at University College London and obtained a B.Sc in 1937. He completed Ph.D in 1954 on a thesis entitled ‘X-ray Diffraction Polypeptides and Proteins”.
- Watson and Crick had common interest in solving the DNA structure. Their first serious effort was unsatisfactory. Their second effort based upon more experimental evidence and better appreciation of nucleic acid literature resulted in the proposal of the complementary double helical configuration in 1953.