A helicase usually initiates unwinding at a single-stranded region adjacent to a duplex. Note that it cannot unwind a segment of duplex DNA; it can only continue to unwind a sequence that has been started.

TLS Online TPP Program

#Id: 5060

#Unit 3. Fundamental Processes

Input of energy in the form of ATP is required at several stages for the prepriming reaction, and it is required for unwinding DNA.

The helicase action of DnaB depends on ATP hydrolysis, and the swivel action of gyrase requires ATP hydrolysis.

ATP also is needed for the action of primase and to load the b subunit of Pol III in order to initiate DNA synthesis.

TLS Online TPP Program

#Id: 2068

#Unit 8. Inheritance Biology

TLS Online TPP Program

#Id: 6338

#Unit 8. Inheritance Biology

ANDROGEN-INSENSITIVITY SYNDROME

These individuals have female external sexual characteristics. Vagina ends blindly and that the uterus, oviducts, and ovaries are absent.

 Inside the abdominal cavity, a pair of testes produce levels of testosterone normally seen in males. 

Woman with androgen-insensitivity syndrome contain an X and a Y chromosome. 

Testosterone bind to an androgen receptor. This receptor is defective in females with androgen-insensitivity syndrome.

The gene for the androgen receptor is located on the X chromosome

TLS Online TPP Program

#Id: 1542

#Unit 2. Cellular Organization

Op18/stathmin (End-Binding Proteins) binds selectively to curved protofilaments and enhances terminal tubulin heterodimer dissociation from a microtubule end. 

 

TLS Online TPP Program

#Id: 2636

#Unit 13. Methods in Biology

S1 mapping the 5’-end of a transcript