Multiple Choice
IP3 (inositol trisphosphate) is produced as a result of __________.
10. Cell Signaling
Signal Amplification
Back10. Cell Signaling
Signal Amplification
- Multiple Choice
Kinases and phosphatases are essential to the cell because they:
a) Are enzymes that synthesize proteins.
b) Are enzymes that degrade proteins.
c) Are enzymes that can turn proteins 'on' and/or 'off' through changes in phosphorylation.
d) Are enzymes that can turn proteins 'on' and/or 'off' through changes in proton concentrations.
e) None of the above.
- Multiple Choice
What role do phosphatases play in signal transduction pathways?
a) They phosphorylate proteins involved in signal transduction or cellular response.
b) They activate protein kinases by phosphorylation.
c) They amplify the signal molecule.
d) They regulate the function of proteins involved in signal transduction pathways or cellular response.
- Multiple Choice
Phosphorylation cascades are useful signal transduction pathways because they ________.
a) Allow proteins to be easily activated by adding or removing a phosphate group.
b) Allow proteins to be easily deactivated by adding or removing a phosphate group.
c) Amplify the original signal many times.
d) All of the above.
- Multiple ChoiceIn liver cells, epinephrine stimulates the breakdown of glycogen. As the signal-transduction pathway progresses, __________.
- Multiple ChoiceThe molecule cAMP usually directly activates __________.
- Multiple ChoiceA mutation in the active site of adenylyl cyclase that inactivates it would most likely lead to __________.
- Multiple ChoiceThe source of phosphate for a phosphorylation cascade is __________.
- Multiple ChoiceThe general name for an enzyme that transfers phosphate groups from ATP to a protein is __________.
- Multiple ChoiceATPgammaS is a form of ATP that cannot be hydrolyzed by enzymes. If this compound were introduced to cells so that it replaced the normal ATP present in the cell, which of the following would you predict?
- Multiple ChoicePhosphorylation __________.
- Multiple ChoiceSecond messengers tend to be water-soluble and small. This accounts for their ability to __________.
- Multiple ChoiceIP3 (inositol trisphosphate) acts by __________.