Three major types of coated vesicles involved in protein trafficking:

1. COPII vesicles

2. COPI vesicles 

3. Clathrin-coated vesicles

TLS Online TPP Program

#Id: 5901

#Unit 3. Fundamental Processes

TLS Online TPP Program

#Id: 5902

#Unit 3. Fundamental Processes

The lagging strand must be synthesized in the form of Okazaki fragments of 1000 bp -2000 bp

TLS Online TPP Program

#Id: 5903

#Unit 3. Fundamental Processes

The source of this breakage is the incorporation of some uracil into DNA in place of thymine. When the uracil is removed by a repair system, the leading strand has breaks until a thymine is inserted. Thus, the lagging strand is synthesized discontinuously and the leading strand is synthesized continuously. This is called semidiscontinuous replication.

TLS Online TPP Program

#Id: 5904

#Unit 3. Fundamental Processes

A new model for the structure of the DNA Pol III complex proposes a three-polymerase core structure, with two Pol III catalytic cores responsible for synthesis of the lagging strand and one for the leading strand.

TLS Online TPP Program

#Id: 5905

#Unit 3. Fundamental Processes

Enzymes responsible for PTJ Helicase is hexameric and motor that melts the duplex and requires ATP hydrolysis—typically 1 ATP is hydrolyzed for each base pair that is unwound.

TLS Online TPP Program

#Id: 5906

#Unit 3. Fundamental Processes

Each DNA helicase moves along ssDNA in a defined direction. This property is referred to as the polarity of the DNA helicase. DNA helicases can have a polarity of either 5’->3’ or 3’->5’.