TLS Online TPP Program

#Id: 6259

#Unit 8. Inheritance Biology

Genes exhibit independent assortment but do not act independently in their phenotypic expression. 

TLS Online TPP Program

#Id: 5032

#Unit 3. Fundamental Processes

FtsZ functions at an early stage of septum formation.

Early in the division cycle, FtsZ is localized throughout the cytoplasm, but prior to cell division FtsZ becomes localized in a ring around the circumference at the mid-cell position.

The structure is called the Z-ring.

TLS Online TPP Program

#Id: 3412

#Unit 3. Fundamental Processes

SOS response in E. coli:

When DNA is extensively damaged (such as by UV light), DNA replication is halted and the number of single-strand gaps in the DNA increases.

RecA protein binds to this damaged, single-stranded DNA, activating the protein’s co-protease activity.

While bound to DNA, the RecA protein facilitates cleavage and inactivation of the LexA repressor. When the repressor is inactivated, the SOS genes, including RecA, are induced;

TLS Online TPP Program

#Id: 3998

#Unit 2. Cellular Organization

One approach is to measure the effect of nicking the DNA. Unconstrained supercoils are released by nicking, whereas constrained supercoils are unaffected. Nicking releases -50% of the overall supercoiling.

Another approach uses the crosslinking reagent psoralen, which binds more readily to DNA when it is under torsional tension. The reaction of psoralen with E. coli DNA in vivo corresponds to an average density of 1 negative super helical turn/200 bp (sigma = -0.05).

TLS Online TPP Program

#Id: 7448

#Unit 5. Developmental Biology

ACR harbours seven transmembrane domains and is embedded in the nuclear membrane of prestalk cells.