Signal Transduction Pathways

Part B

Which of these is responsible for initiating a signal transduction pathway?

Correct

This is a signal molecule. The attachment of a signal molecule to a plasma membrane receptor initiates a signal transduction pathway.

Part C

What role does a transcription factor play in a signal transduction pathway?

By binding to a plasma membrane receptor it initiates a cascade.

It relays a signal from the cytoplasm to the plasma membrane.

It activates relay proteins.

By binding to DNA it triggers the transcription of a specific gene.

It is a plasma membrane protein that binds signal molecules.

Correct

This is the function of a transcription factor.

Part D

In this animation, which of the following, when activated by a signal transduction pathway, moved from the cytoplasm to the nucleus of a cell?

To view the animation, click here. Then click on the image to start the animation.

Correct

Activated transcription factors trigger transcription.

Part F

A signal transduction pathway is initiated when a _____ binds to a receptor.

Correct

The binding of a signal molecule to a receptor initiates a signal transduction pathway.

Part G

Which of these acts as a second messenger?

Correct

Cyclic AMP can act as second messengers.

Part H

Calcium ions that act as second messengers are stored in _____.

Correct

The ER stores calcium ions.

Part I

_____ catalyzes the production of _____, which then opens an ion channel that releases _____ into the cell’s cytoplasm.

Protein kinase … PIP2 … Na⁺

Phospholipase C … IP3 …. Ca²⁺

Adenylyl cyclase … cyclic AMP … Ca²⁺

Phospholipase C … cyclic AMP … Ca²⁺

Adenylyl cyclase … IP3 …. Ca²⁺

Correct

Phospholipase C cleaves IP3 from a membrane protein, and IP3 then binds to a calcium channel on the ER.

Part J

A protein kinase activating many other protein kinases is an example of _____.

Correct

By activating many other molecules the initial signal is amplified.

Think!