e) xtended, 17. Which of the following mechanisms of activation is characteristic of tyrosine kinase receptor activation? a) ion conductance b) dissociation of repressor protein c) G-protein signalling d) Receptor internalization e) None of the above

If a cell developed a mutation in its MAP2K1 gene (encodes the MEK protein) that prevented MIEK from being recognized by phosphatases, how would the EGFR signaling cascade and the cell’s behavior change?

When growth hormone binds to an enzyme-linked receptor, (a) G proteins are amplified into a cascade of molecules (b) the enzyme portion of the receptor becomes dephosphorylated (c) the receptor becomes activated and phosphorylates signaling proteins in the cell (d) an ion channel is opened (e) an immediate signal is sent into the nucleus, and specific genes are activated or inhibited

How can a cell use an extracellular peripheral protein as the receptor to transmit a signal into the cell?

What is the sequence of events that takes place in cell signaling?

During signal transduction (a) the cell converts an extracellular signal into an intracellular signal that leads to a change in some cell process (b) a signaling molecule directly activates or represses several genes (c) each enzyme catalyzes production of one molecule of product (d) enzymes in the signal cascade remain active until the last component of the pathway alters a cellular process (e) the signal is terminated by cyclic AMP

How does NF-kB induce gene expression? A small, hydrophobic ligand binds to NF-kB, activating it. Phosphorylation of the inhibitor Ik-B dissociates the complex between it and NF- kB, and allows NF-kB to enter the nucleus and stimulate transcription. NF-kB is phosphorylated and is then free to enter the nucleus and bind DNA. NF-kB is a kinase that phosphorylates a transcription factor that binds DNA and promotes protein production.

Aspirin is a non-steroidal anti-inflammatory drug (NSAID) that inhibits the formation of blood clots and is taken regularly by individuals with a heart condition. Steroids such as cortisol are used to control some autoimmune diseases and severe arthritis by down regulating the inflammatory response. After reading the role of inflammation in the bodys response to infection, can you predict an undesirable consequence of taking anti inflammatory drugs on a regular basis?

Discuss Concepts Why do you suppose cells evolved internal response mechanisms using molecules that bind GTP instead of ATP?

What steps are necessary for Cdk to become fully active?