Dollo’s law:  A biological generalization positing that complex characters, once lost in evolution, are extremely unlikely to reappear and thus the loss of complex characters is virtually always irreversible.

TLS Online TPP Program

#Id: 9294

#Unit 6. System Physiology – Plant

Nitrate reductase

Homodimers, two identical subunits

Each subunit with 100kD

Each subunit contains 3 prosthetic groups:

FAD, heme, and molybdenum complexed to pterin (an organic molecule). 

TLS Online TPP Program

#Id: 1109

#Unit 2. Cellular Organization

E2’s ion binding sites are exposed to the exterior of the cell and it has low affinity for Na+ but high affinity for K+

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#Id: 2030

#Unit 8. Inheritance Biology

TLS Online TPP Program

#Id: 7506

#Unit 4. Cell Communication and Cell Signaling

RAG1 subunit and contains two aspartic acid residues and one glutamic acid residue (D600, D708, and E962, respectively). This active site “DDE motif” is found in many enzymes that cleave DNA

TLS Online TPP Program

#Id: 4741

#Unit 5. Developmental Biology

The decision of the anterior and posterior axis depends on the position of the sperm pronucleus in egg.