TLS Online TPP Program

#Id: 2891

#Unit 3. Fundamental Processes

the origin has been opened (and the DNA is single-stranded) by its ability to further unwind the DNA.

TLS Online TPP Program

#Id: 3210

#Unit 4. Cell Communication and Cell Signaling

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: 3600

#Unit 3. Fundamental Processes

All the amino acids except methionine and tryptophan have more than one codon.

TLS Online TPP Program

#Id: 8207

#Unit 2. Cellular Organization

Anthocyanin pigments stored in vacuoles

Color the petals of many flowers so as to attract pollinating insects