The miRNAs miR-15-a and miR-16-1 act like tumor-suppressors; they normally inhibit cell proliferation, and their absence leads to cell growth.

TLS Online TPP Program

#Id: 6130

#Unit 3. Fundamental Processes

Alkyladenine DNA glycosylase (AAG), recognizes and removes a variety of alkylated substrates, including 3-methyladenine, 7-methylguanine, and hypoxanthine. 

TLS Online TPP Program

#Id: 3067

#Unit 10. Ecological Principles

Species turnover on islands is generally low - The number of species on an island might remain the same, but the composition of the species should change continuously as new species colonize the island and others become extinct.

TLS Online TPP Program

#Id: 9446

#Unit 4. Cell Communication and Cell Signaling

The cytokines form a family of relatively small, secreted signaling molecules:

Contain about 160–200 AA

4 long, conserved α helices

Control growth and differentiation

TLS Online TPP Program

#Id: 7518

#Unit 6. System Physiology – Plant

Auxin influx 

Auxin can enter plant cells from any direction by either of two mechanisms:

Passive diffusion of the protonated (IAAH) form across the phospholipid bilayer

Secondary active transport of the dissociated (IAA–) form via a 2H+–IAA– symporter

The dual pathway of auxin uptake arises because the passive permeability of the membrane to auxin depends strongly on the apoplastic pH.

TLS Online TPP Program

#Id: 6657

#Unit 3. Fundamental Processes