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 producer?

TLS Online TPP Program

#Question id: 31034

#Unit 4. Cell Communication and Cell Signaling

In nucleus PKA phosphorylate serine-133 on a transcription factor called as:

TLS Online TPP Program

#Question id: 31035

#Unit 4. Cell Communication and Cell Signaling

Which of the following is not a RTK ligand? 

TLS Online TPP Program

#Question id: 31036

#Unit 4. Cell Communication and Cell Signaling

In the resting, unstimulated (no ligand bound) state, the intrinsic kinase activity of an RTK is very low because:

Activation loop is not phosphorylated

Activation loop is phosphorylated

Phosphorylated loop prevents binding of substrate

Unphosphorylated loop prevents binding of substrate

Which of the following combination is incorrect?

TLS Online TPP Program

#Question id: 31037

#Unit 4. Cell Communication and Cell Signaling

In some receptors (e.g., the insulin receptor), unphosphorylated activation loop prevents:

TLS Online TPP Program

#Question id: 31038

#Unit 4. Cell Communication and Cell Signaling

For most, but not all, RTKs, the weakly active kinase in each subunit is thought to phosphorylate a key  residue, known as:

TLS Online TPP Program

#Question id: 31039

#Unit 4. Cell Communication and Cell Signaling

Phosphorylation of tyrosine in activation loop leads to a conformational change in the activation loop that unblocks the kinase active site for either ATP or the substrate by:

Reducing the Kd 

Increasing the Kd

Reducing the affinity

Increasing the affinity

Which of the following combination is correct?