Chapter 7.3.2 (Exam 4) Second Messengers Flashcards
Signal Transduction Spreads the Response to a Signal through the Cell (10 cards)
What are second messengers?
Small molecules that diffuse through the cytosol to mediate some steps in a cascade
What is the role of second messengers in signal transduction pathways?
Amplify and distribute the signal
What are some examples of second messengers?
cyclic AMP (cAMP)
phospholipids
Ca2+
NO
How does cAMP formation amplify a signal transduction pathway?
Binding of one signal molecule to a receptor can lead to production of many of cAMP, which activates many enzyme targets
How does cAMP relate to the breakdown of glucose in the fight or flight response?
Once epinephrine binds to a receptor, it activates the enzyme, adenylyl cyclase, which converts ATP to cAMP
cAMP activates protein kinase A which activates the enzyme, glycogen phosphorylase, which then breaks down glycogen into glucose
Can second messengers be involved in crosstalk?
Yes
What can some second messengers be formed by? What is one example of this?
Some second messengers are formed from membrane phospholipids
Hydrolysis of PIP2 results in two second messengers: IP3 and DAG
What is the role of IP3 and DAG?
Activating protein kinase C (PKC)
How can Ca2+ ions act as second messengers?
Ca2+ can also activate protein kinase C (PKC)
What are 2 instances when Ca2+ channels can open?
IP3 and other signal can open Ca2+ channels
Entry of a sperm into an egg cell also opens Ca2+ channels
