TLS Online TPP Program

#Id: 1391

#Unit 4. Cell Communication and Cell Signaling

Actin thin filaments and myosin II thick filaments assemble into contractile structures.

TLS Online TPP Program

#Id: 9713

#Unit 4. Cell Communication and Cell Signaling

Ste20 phosphorylates and activates Ste11, a serine/threonine kinase

TLS Online TPP Program

#Id: 5330

#Unit 7. System Physiology – Animal

Rapid Ventricular Filling

The rapid flow of blood from the atria to the ventricles produces the third heart sound (S3).

TLS Online TPP Program

#Id: 2334

#Unit 3. Fundamental Processes

The E. coli rrn  promoters are also regulated by a pair of small molecules: the initiating NTP (the iNTP) and an alarmone,  guanosine 5 -diphosphate 3-diphosphate (ppGpp). 

1. An abundance of iNTP indicates that the concentration of  nucleotides is high, and therefore it is appropriate to synthesize plenty of rRNA. 

2. Accordingly, iNTP stabilizes the open promoter complex, stimulating transcription. 

3. On the other hand, when cells are starved for amino acids, protein synthesis cannot occur readily and the need for ribosomes (and rRNA) decreases. 

TLS Online TPP Program

#Id: 1513

#Unit 2. Cellular Organization

Microtubules exist in three forms:

Singlet

Doublet

Triplet