In the Following Schematic Diagram of a Simple Signaling Pathway

question 21

Multiple Choice

In the following schematic diagram of a simple signaling pathway, protein Z regulates the activity of protein X, which is an upstream protein kinase, through a negative feedback loop. Which of the following better describes protein Z?

• A) It is a protein kinase that is activated by phosphorylation.
• B) It is a protein kinase that is inactivated by phosphorylation.
• C) It is a protein phosphatase that is activated by phosphorylation.
• D) It is a protein phosphatase that is inactivated by phosphorylation.

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Definitions:

Operating Lease

An agreement permitting the utilization of a property without transferring ownership rights to it.

Lessor

The party in a lease agreement that owns the asset and grants the lessee the right to use the asset in return for lease payments.

Bargain Purchase Option

A lease clause allowing the lessee to purchase the leased asset at a price significantly lower than its expected fair market value at the end of the lease term.

Leased Asset's Useful Life

The expected period over which a leased asset is anticipated to be used by the lessee, often corresponding to the lease term unless a shorter period is more representative.