The number of species should decrease with increasing distance of the island from the mainland - The species distance hypothesis

TLS Online TPP Program

#Id: 10291

#Unit 4. Cell Communication and Cell Signaling

The second phase of T-cell development

1.Positive selection: Selection for those cells whose T-cell receptors engage self-MHC.

2.Negative selection: Selection against those cells whose T-cell receptors bind too strongly to self-peptide/MHC combinations.

3.Lineage commitment: Commitment of thymocytes to effector cell lineages, including CD4 helper or CD8 cytotoxic populations

TLS Online TPP Program

#Id: 10292

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 10293

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 10294

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 10295

#Unit 4. Cell Communication and Cell Signaling

Allelic exclusion - Once allele’s functional protein is generated, rearrangement at the other allele is shut down

TLS Online TPP Program

#Id: 10296

#Unit 4. Cell Communication and Cell Signaling

T Cells Undergo Positive and Negative Selection