TLS Online TPP Program

#Id: 9283

#Unit 6. System Physiology – Plant

Three factors are important in maintaining low O2 concentrations in nodules. 

First, entry of O2 into the nodule is controlled by a variable‐permeability barrier in the nodule parenchyma

TLS Online TPP Program

#Id: 2375

#Unit 5. Developmental Biology

 Wnt signaling achieves its repression of head regeneration by inhibiting Erk

TLS Online TPP Program

#Id: 1465

#Unit 4. Cell Communication and Cell Signaling

Three classes of classical cadherins: 

E-cadherin -present on many types of epithelial cells

N-cadherin - present on nerve, muscle and lens cells

P-cadherin - present on cells in the placenta & epidermis

TLS Online TPP Program

#Id: 9289

#Unit 6. System Physiology – Plant

TLS Online TPP Program

#Id: 9203

#Unit 11. Evolution and Behavior

Balance natural selection

Balancing selection is a type of natural selection that maintains genetic diversity in a population.

In balancing selection, two or more alleles are kept in balance, and therefore are  maintained in a population over the course of many generations.