The absorption of UV light by nucleic acids arises from n ® p* and p ® p* transitions of the purine and pyrimidine bases that occur between 260nm and 275 nm.

TLS Online TPP Program

#Id: 692

#Unit 3. Fundamental Processes

Mutants that used to analyse Replication Machinery are usually Conditional Lethals

TLS Online TPP Program

#Id: 693

#Unit 3. Fundamental Processes

Permissive conditions are those whose in which mutants performs replication

TLS Online TPP Program

#Id: 694

#Unit 3. Fundamental Processes

Quick-stop mutants are defective in the components of the replication apparatus and cease replication immediately upon a temperature increase.

TLS Online TPP Program

#Id: 695

#Unit 3. Fundamental Processes

1. DNA polymerase I is a single polypeptide of 103 kD. 

2. The chain can be cleaved into two parts by proteolytic treatment. The larger cleavage product (68 kD) is called the Klenow fragment. It is used in synthetic reactions in vitro. 

3. It contains the polymerase and the proofreading 3’–5’ exonuclease activities.

TLS Online TPP Program

#Id: 696

#Unit 3. Fundamental Processes

1. The small fragment (35 kD) possesses a 5’– 3’ exonucleolytic activity, which excises small groups of nucleotides, up to 10 bases at a time.

2. This activity is coordinated with the synthetic/ proofreading activity. 

3. It provides DNA polymerase I with a unique ability to start replication in vitro at a nick in DNA.

TLS Online TPP Program

#Id: 697

#Unit 3. Fundamental Processes

Substitutions occurs when Proofreading fails