Active brassinosteroids are also regulated by brassinosteroid-dependent negative feedback mechanisms attenuation which is brought about by the downregulation of brassinosteroid biosynthetic genes and the upregulation of genes involved in brassinosteroid catabolism.

TLS Online TPP Program

#Id: 1764

#Unit 4. Cell Communication and Cell Signaling

Self antigens are not uncommon in the periphery, Two factors contribute to this:                                                                                                                             a. not all self a. antigens are expressed in the central lymphoid organs where negative selection occurs

b. there is a threshold requirement for affinity to self antigens before clonal deletion is triggered, allowing some weakly self-reactive clones to survive the weeding-out process.

TLS Online TPP Program

#Id: 4025

#Unit 7. System Physiology – Animal

Large quantities of positive potassium ions diffuse out of the SA node.

TLS Online TPP Program

#Id: 8812

#Unit 6. System Physiology – Plant

Excitation of chlorophyll RC has four ways to dissipate energy

1. Heat

2. Fluorescence

3. energy transfer

4. Photochemistry via charge separation

TLS Online TPP Program

#Id: 6538

#Unit 7. System Physiology – Animal

The insulin receptor, a receptor tyrosine kinase, activates several signal transduction pathways, including the one leading to the activation of protein kinase B

TLS Online TPP Program

#Id: 1466

#Unit 4. Cell Communication and Cell Signaling

Nonclassical cadherins include proteins:

• Protocadherins found in the brain

• Desmocollins and desmogleins that form desmosomes