Phylogenetic relationships among species in a radiation are difficult to determine for two related reasons.                                                                 

a. During the short time between two successive speciation events, few new mutations are fixed.                                                                               

b. Incomplete lineage sorting may occur during rapid diversification.

TLS Online TPP Program

#Id: 6035

#Unit 3. Fundamental Processes

TLS Online TPP Program

#Id: 10393

#Unit 4. Cell Communication and Cell Signaling

Precancerous cells have: 

lost contact inhibition

less adherent and more rounded than normal cells

continue to divide

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#Id: 2556

#Unit 13. Methods in Biology

When excited by absorption of a photon of light, GFP emits a photon (that is, it fluoresces) in the green region of the spectrum. 

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#Id: 832

#Unit 4. Cell Communication and Cell Signaling

Biotrophy where the plant cells remain alive throughout infection

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#Unit 3. Fundamental Processes

Two bases in the non-template strand of the –10 element (A11 and T7) flip out from their base-stacking interactions and instead insert into pockets within the sigma protein where they make more favorable interactions for OPC