Cell Signalling and Transduction Objective Questions and Answers

22. The enzyme that catalyzes the splitting of PIP2 into two molecules of inositol triphosphate (IP3) and diacylglycerol in cell signaling, is

23. The binding of ligands to many G-proteins linked receptors leads to shortlived

A. increase in the concentration of certain intracellular signaling molecules called second messenger

B. decrease in the concentration of certain intracellular signaling molecules called second messenger

C. increase in the concentration of certain extracellular signaling molecules called first messenger

D. decrease in the concentration of certain extracellular signaling molecules called first messenger

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24. 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?

A. Signal transduction

B. B. Signal reception

C. Signal integration

D. Signal amplification

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25. A signal cascade induced by adrenaline or thyroxine

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

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26. Which of the following is a second messenger?

A. lnositol 1,4,5-triphosphate

27. Which of the following statement is incorrect?

A. The principal lipophilic hormones that binds to receptors located in the plasma membranes are prostaglandins

B. Prostaglandins are synthesized from arachidonic acid

C. Prostaglandins act as paracrine signaling molecules

D. None of the above

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28. Two key organizing principles for large multicellular organisms are

A. prokaryotic cell structure and cell specialization

B. cell specialization and communication between cells

C. communication between cells and simple nerve reflexes

D. simple nerve reflexes and cell specialization

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Biochemistry Objective Questions { Cell Signalling and Transduction }