T-Cell Development

a. Commitment of hematopoietic precursors to the T cell lineage

b. The initiation of antigen receptor gene rearrangements

c.  The selection and expansion of cells that have successfully rearranged one of their T-cell receptor genes (-selection).

TLS Online TPP Program

#Id: 9264

#Unit 6. System Physiology – Plant

TLS Online TPP Program

#Id: 9265

#Unit 6. System Physiology – Plant

TLS Online TPP Program

#Id: 9266

#Unit 6. System Physiology – Plant

N2 constitutes about 80% of the earth’s atmosphere, but the stability of its triple bond renders it inert and metabolically inaccessible to most organisms.

TLS Online TPP Program

#Id: 9267

#Unit 6. System Physiology – Plant

Diazotrophs are able to catalyze the enzymatic reduction of this compound to ammonia (NH3) using the enzyme nitrogenase

TLS Online TPP Program

#Id: 9268

#Unit 6. System Physiology – Plant

Nitrogenase is a complex consisting of the MoFe protein (dinitrogenase or component I) a heterotetramer, and the Fe protein (dinitrogenase reductase or component II) a homodimer.

TLS Online TPP Program

#Id: 9269

#Unit 6. System Physiology – Plant

Fe protein 

contains 2 identical subunits (dimer) – nif H

Each subunit has MW of 30 ~ 72 kD.

Each subunit contains an Fe-S cluster (4Fe and 4S2-).