Postulate of Darwin

Geometric increase 

Limited food & Space

Struggle for existence 

Variation 

 Natural selection

Inheritance of useful characters

Speciation

TLS Online TPP Program

#Id: 6322

#Unit 3. Fundamental Processes

Nonsense mutation in one gene of a transcription unit was found to prevent the expression of subsequent genes in the unit even though both genes had their own ribosome binding sites, an effect called polarity.

TLS Online TPP Program

#Id: 6323

#Unit 3. Fundamental Processes

Rho-dependent termination sites within a transcription unit are usually masked by translating ribosomes and therefore rho cannot act on downstream RNA polymerases

TLS Online TPP Program

#Id: 6324

#Unit 3. Fundamental Processes

Nonsense mutations release ribosomes within the RNA of a multigene operon, though, enabling rho to terminate transcription prematurely and prevent expression of distal genes in the transcription unit even though their open reading frames contained wild-type sequences.

TLS Online TPP Program

#Id: 6325

#Unit 3. Fundamental Processes

The b-subunit is obviously the determinant of rifampicin sensitivity or resistance.

TLS Online TPP Program

#Id: 758

#Unit 3. Fundamental Processes

The overall reaction rate for the bacterial RNA polymerase can be as fast as 40–50 nucleotides/second at 37°C for most transcripts; this is about the same as the rate of translation (15 amino acids/sec), but much slower than the rate of DNA replication (800 bp/sec).

TLS Online TPP Program

#Id: 759

#Unit 3. Fundamental Processes

Four Steps for bacterial transcription

1. Promoter search->closed promoter complex -> open promoter complex

2. Abortive transcription->Promoter Escape->Initiation from +1 TSS 

3. Elongation

4. Termination