cAMP and cGMP are derived from ATP and GTP by the actions of adenylate cyclase a

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Question
cAMP and cGMP are derived from
Options
A. ATP and GTP by the actions of adenylate cyclase and guanylate cyclase respectively
B. GTP and ATP by the actions of adenylate cyclase and guanylate cyclase respectively
C. ATP and GTP by the actions of guanylate cyclase and adenylate cyclase respectively
D. none of the above

Correct Answer

ATP and GTP by the actions of adenylate cyclase and guanylate cyclase respectively

Cell Signalling and Transduction problems

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1. Nitroglycerin has long been administered to human patients suffering from chronic chest pain (angina). This medication works because it
Options
A. mimics the action of signal receptors
B. is broken down into hormones that affect the heart
C. interferes with chemical cascades that trigger contraction of heart muscle
D. breaks down into nitric oxide, which increases blood flow to the heart

2. When a __________ reaches its __________ , there is a specific means of receiving it and acting on the message. This task is the responsibility of specialized proteins called __________ .
Options
A. signaling molecule; receptor; G proteins
B. signaling molecule; target cell; G proteins
C. signaling molecule; target cell; receptors
D. kinase; receptor; proteases

4. Self-phosphorylation is an excellent mechanism for triggering specific catalytic function of the proteins involved in signal cascades because it
Options
A. changes the shape and thus the enzymatic activity of the proteins involved
B. makes the receptor more likely to capture the signaling, molecule
C. allows hydrophilic signaling molecules to cross the plasma membrane
D. None of the above

5. A signal cascade induced by adrenaline or thyroxine
Options
A. must begin with receipt of the signal molecule by a surface receptor
B. involves the activation of a G protein
C. results in the activation of a sequence of enzymes needed for the cell effect
D. all of the above

6. Which of the following processes involve the combining of a message from one signaling molecule with that of another to either enhance or inhibit a cellular effect?
Options
A. Signal transduction
B. Signal reception
C. Signal integration
D. Signal amplification

7. Which of the following statements about G proteins is false?
Options
A. They are involved in signal cascades
B. They bind to and are regulated by guanine nucleotides
C. They become activated when bound to GDP
D. They must be active before the cell can make needed cAMP

8. A cell is known to respond to a particular signaling molecule. Which of the following must be true of this cell?
Options
A. It is in the heart muscle
B. It is also the site of production for the signaling molecule
C. It contains the receptor for the signaling molecule
D. It is incapable of signal transduction

9. The signaling molecules called steroid hormones
Options
A. are made in one location of the body but have their effects some distance away
B. are hydrophilic and so cannot penetrate the plasma membrane
C. bind to cell surface receptors to trigger chemical cascades
D. never enter the blood of humans

10. In the signal transduction mechanism known as protein phosphorylation
Options
A. the signaling molecule binds to a surface receptor
B. receptor kinases play a key role in triggering the signal cascade
C. phosphorylated proteins act with enzymes to trigger the signal cascade
D. All of the above

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