Molecular basis of inheritance

Transcription

Types of RNA

Genetic and non genetic

Genetic RNA

Present only in some virus

HIV

TMV

QB Bacteriophage

COVID 19

Reo virus

r- RNA

Most abundant (80%)

Most stable and structural

Synthesis of r- RNA

• In eukaryotes, nucleolous (5s r- RNA in nucleoplasm)

• In prokaryotes, cytoplasm

Specialties of r- RNA

• Act as catalyst (ribozyme)

• Prokaryotes (23s r- RNA)

• Eukaryotes (28s r- RNA)

Total types of r- RNA in pro and eu and combinely?

• Prokaryotes 3

• Eukaryotes 4

• Combine 6

t- RNA

• Adopter RNA , s- RNA , carrier RNA

• 2nd most abundant RNA (10.- 15 %)

• Smallest RNA

• Picks up amino acid during protein synthesis

Structure of t- RNA

• Complicated

• 2D ( clove leaf like) holly

• 3D ( inverted L like) kimm , actual

No. Of bases in DHU loop and anticodon loop

DHU 8-12

Anticodon 7

Where is COOH group attach on t- RNA

3’ end

Function of 3 loops in t- RNA

1) helps to attach to larger subunit of ribosome

2) recognise specific amino acetate synthetase enzyme

3) recognise its place on m- RNA

m- RNA

Least stable

Produce from genetic DNA in nucleus

Template RNA

Who reads the genetic code

t- RNA

How is transcription initiated

Promoter gets binded by RNA polymerase

Transcription

Process of copying of genetic information from one strand of DNA to RNA

Principle in transcription

Complementary based pairing

Transcriptional unit

Promoter

Structural gene

Terminator

Which enzyme catalyses transcription

DNA dependent RNA polymerase enzyme

Who provides binding site for RNA polymerase

DNA sequence

Structural gene in transcription unit

Monocistron ( eukaryotes)

Polycistron ( prokaryotes)

Exons and introns

Exons and introns

Appear in mature or processed RNA

Interrupt the exons ( do not appear in mature RNA )

Inheritance of character is affected by

1 promoter

2 regularity in sequence of structural gene

RNA polymerase catalyses which process

Elongation

Speciality of bacteria

Transcription and translation can be a coupled rxn

Work of 3 RNA polymerase enzymes

1) transcribes r RNA 28s , 18s , 5.8s

2) transcribes hn RNA

3) transcribes t RNA , 5sr RNA , sn RNA

Explain splicing , capping and tailing

In ncert

What does split gene arrangement show

An ancient feature of the genome

What does presence of introns and splicing indicate

1) introns ( reminiscent of antiquity)

2) splicing ( dominance of RNA World)