In response to a depolarizing stimulus, some of the voltage-gated Na+ channels open and Na+ enters the cell and the membrane is brought to its threshold potential (approximately −55 mV)

TLS Online TPP Program

#Id: 6006

#Unit 3. Fundamental Processes

ATP is required for the binding, but is not hydrolyzed until a later stage. The transcription factor ABF1 binds to the B3 element; this assists initiation by affecting chromatin structure, but it is the events that occur at the A and B1 elements that actually cause initiation

TLS Online TPP Program

#Id: 1597

#Unit 5. Developmental Biology

Mediolateral intercalation in the formation of the primitive streak (Cellular Dance Mechanism) cells came down the sides of the epiblast to undergo a medially directed intercalation of cells in the posterior margin

TLS Online TPP Program

#Id: 932

#Unit 5. Developmental Biology

A totipotent stem cell can generate all cell types of both embryonic and extraembryonic lineages. 

TLS Online TPP Program

#Id: 8234

#Unit 10. Ecological Principles

Negative density dependence occurs when the rate of population growth decreases as population density increases.

Ex - limited supply of resources, such as food, nesting sites, and physical space.

TLS Online TPP Program

#Id: 5762

#Unit 10. Ecological Principles

More diverse communities have a lower value of DBP than less-diverse communities.