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TLS Online TPP Program

#Question id: 32280

When proteins are experimentally extracted from the nucleus and reintroduced into the cytosol, even the very large ones reaccumulate efficiently in the nucleus, due to the presence of:

#Unit 2. Cellular Organization
  1. Nuclear export signals
  2. Nuclear localization signals
  3. Nuclear pore complex
  4. Nucleoporins 
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TLS Online TPP Program

#Question id: 8778

#Unit 9. Diversity of Life Forms

The following question refers to this phylogenetic tree, depicting the origins of life and the three domains. Horizontal lines indicate instances of gene or genome transfer.

A possible phylogenetic tree for the three domains of life.

If the early history of life on Earth is accurately depicted by the figure, then which statement is most in agreement with the hypothesis proposed by this tree?
TLS Online TPP Program

#Question id: 14686

#Unit 4. Cell Communication and Cell Signaling

This member of the AKAP family, designated mAKAP, anchors both PDE and the regulatory subunit  of PKA to the nuclear membrane, maintaining them in a negative feedback loop that provides close local control of the ATP level and PKA activity.
B- The basal level of PDE activity in the presence of hormone (resting state) keeps cAMP levels below those necessary for PKA activation. 
C- Activation of β-adrenergic receptors causes an increase in cAMP to a level in excess of that which can be degraded by PDE. 
D- The resulting binding of cAMP to the R subunits of PKA releases the active catalytic (C) subunits into the cytosol. Some C subunits enter the nucleus, where they phosphorylate and thus activate certain transcription factors . Other C subunits phosphorylate PDE, stimulating its catalytic activity.
E-  Active PDE hydrolyzes cAMP, thereby driving cAMP levels back to basal levels and causing re-formation of the inactive PKA C-R complex. Subsequent de-phosphorylation of PDE returns the complex to the resting state.
TLS Online TPP Program

#Question id: 19202

#Unit 12. Applied Biology

Acoustic wave or piezoelectric biosensor is a type of a biosensor which employs
TLS Online TPP Program

#Question id: 12132

#Unit 10. Ecological Principles

Use the following diagram of a hypothetical food web to answer the following questions. The arrows represent the transfer of food energy between the various trophic levels.

Which letter represents an organism that could be a primary consumer?
TLS Online TPP Program

#Question id: 3906

#Unit 3. Fundamental Processes

Which subunit of the E. coli core RNA polymerase (a2bbʹw) contributes to DNA binding?

A) a                 B) b                 C) bʹ                D) w