FREE PHYSIOLOGY AND STUDY GAMES ABOUT BIOL 201

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FREE PHYSIOLOGY AND STUDY GAMES ABOUT BIOL 201

EXAM QUESTIONS

Actual Qs and Ans Expert-Verified Explanation

This Exam contains:

-Guarantee passing score -31 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation Question 1: a chemical messenger that binds to a receptor and triggers the cell's

response; often refers to a drug that mimics a normal messengers action. Ex:

Decongestants

Answer:

Agonist

Question 2: enzyme that catalyzes transformation of ATP to cyclic AMP (cAMP)

Answer:

Adenylyl cyclase Question 3: a decrease in the total number of target-cell receptors for a given messenger; may occur in response to chronic high extracellular concentration of the messenger

Answer:

Down-regulation Question 4: second messenger that activates protein kinase C, which then phosphorylates a large number of other proteins

Answer:

Diacylglycerol (DAG)

Question 5: cyclic nucleotide that acts as second messenger in some cells

Answer:

cGMP

Question 6: enzyme that catalyzes cyclic AMP breakdown to AMP

Answer:

Phosphodiesterase Question 7: membrane channel operated by the binding of specific molecules to channel proteins

Answer:

Ligand-gated Channel Question 8: a specific protein in either the plasma membrane or the interior of a target cell that a chemical messenger combines within thereby invoking a biologically relevant response in that cell

Answer:

Receptor (receptor protein) Question 9: the increased responsiveness of a target cell to a given messenger; may result from up-regulation of receptors

Answer:

Supersensitivity Question 10: enzyme that phosphorylates certain intracellular proteins when activated by diacylglycerol

Answer:

Protein kinase C Question 11: substances that enter or are generated in the cytoplasm as a result of receptor activation by the first messenger

Answer:

Second Messengers

Question 12: enzyme that is activated by cyclic GMP, and then phosphorylates specific proteins, thereby altering their activity

Answer:

cyclic GMP-dependent protein kinase

Question 13: the strength with which a chemical messenger binds to its receptor

Answer:

Affinity Question 14: the major type of receptor protein that is itself an enzyme; these receptors are on plasma membranes and respond to many different water-soluble chemical messengers

Answer:

Receptor Tyrosine Kinase Question 15: an increase in the total number of target-cell receptors for a given messenger; may occur in response to a chronic low extracellular concentration of the messenger.

Answer:

Up-regulation Question 16: intracellular calcium-binding protein that mediates many of calcium's second-messenger functions

Answer:

Calmodulin Question 17: one of a class of proteins that act as gene switches, regulating the transcription of a particular gene by activating or repressing the initiation process

Answer:

Transcription Factor Question 18: any enzyme that phosphorylates other proteins by transferring a phosphate group to them from ATP

Answer:

Protein Kinase

Question 19: sequence of mechanisms that relay information from plasma-membrane receptor to cell's response mechanism

Answer:

Signal Transduction Pathway Question 20: a molecule that competes for a receptor with a chemical messenger normally present in the body. Binds to the receptor but does not trigger the cell's response. Ex; Antihistamines

Answer:

Antagonist Question 21: cyclic nucleotide that serves as a second messenger for many "first" chemical messengers

Answer:

Cyclic AMP (cAMP) Question 22: enzyme that is activated by cyclic AMP and then phosphorylates specific proteins, thereby altering their activity

Answer:

cAMP-dependent protein kinase Question 23: the degree to which receptors are occupied by messengers. If all are occupied, the receptors are fully saturated; 100%, and so on

Answer:

Saturation Question 24: the intercellular chemical messengers that reach the cell from the extracellular fluid and bind to their specific plasma membrane receptors

Answer:

First Messengers Question 25: one protein from a family of regulatory proteins that reversibly bind guanosine nucleotides; these interact with membrane ion channels or enzymes

Answer:

G protein