Urea transporters UT-A1 and UT-A3 facilitate diffusion of urea out of the medullary collecting ducts while UT-A2 facilitates urea diffusion into the thin descending loop of Henle.

TLS Online TPP Program

#Id: 3204

#Unit 3. Fundamental Processes

Recombination-repair systems use recombination to replace the double-stranded region that has been damaged.

TLS Online TPP Program

#Id: 3205

#Unit 3. Fundamental Processes

.All these systems are prone to introducing errors during the repair process. 

TLS Online TPP Program

#Id: 3206

#Unit 3. Fundamental Processes

Photoreactivation is a nonmutagenic repair system that acts specifically on pyrimidine dimers

TLS Online TPP Program

#Id: 3207

#Unit 3. Fundamental Processes

Deamination of cytosine creates a U-G base pair. Uracil is preferentially removed from the mismatched pair

TLS Online TPP Program

#Id: 3215

#Unit 3. Fundamental Processes

Ultraviolet irradiation causes dimer formation between adjacent thymines. The dimer blocks replication and transcription. 

TLS Online TPP Program

#Id: 3217

#Unit 3. Fundamental Processes

The Uvr system makes incisions -12 bases apart on both sides of damaged DNA, removes the DNA between them, and resynthesizes new DNA.