OD 515 Cell Signals & Hormones Questions Exam 1
with complete solutions.
What is signal transduction?
The conversion of information into a chemical change that results in a cellular response.
What are G-Protein Coupled Receptors (GPCRs)?
The largest group of plasma membrane receptors that act through intracellular G proteins
activated by binding guanosine triphosphate (GTP).
What physiological effects are associated with sympathetic activation?
Increases heart rate, bronchodilation, and mobilizes energy reserves (fight or flight response).
What physiological effects are associated with parasympathetic activation?
Decreases heart rate, promotes relaxation and restoration (rest and digest response).
How do agonists and antagonists differ?
Agonists activate receptors and produce effects of the natural ligand, while antagonists block
receptor effects.
What is the role of phosphorylation in signaling?
Functions as a switch to toggle enzyme activities and create binding sites for other molecules.
What is signal amplification?
The process where one activated enzyme catalyzes the activation of many molecules of a second
enzyme, creating a cascading effect.
,What are the four general types of adrenergic receptors?
α1, α2, β1, and β2.
What is the primary role of the sympathetic nervous system?
Triggers the 'fight or flight' response.
What is desensitization in cell signaling?
When a cell becomes unresponsive to a signal due to continuous presence of that signal.
What is the significance of second messengers in GPCR signaling?
They mediate the cellular responses initiated by activated G proteins.
What is the effect of the drug Propranolol?
It acts as a beta-adrenergic antagonist, reducing heart rate and blood pressure.
What is the difference between cholinergic and adrenergic pathways?
Cholinergic pathways use acetylcholine, while adrenergic pathways use epinephrine and
norepinephrine.
What is the function of gated ion channels in signaling?
They are crucial for cell signaling processes and can be opened by membrane potential or ligand
binding.
What does specificity in receptor signaling refer to?
The precise molecular complementarity between the signal and receptor molecules.
What is the role of enzyme cascades in signaling?
, They amplify the signal by activating multiple enzymes in a sequence.
What is the impact of defective signaling proteins?
They can disrupt cell cycle regulation and potentially lead to tumor formation (cancer).
What is the role of intracellular hormones?
They often regulate gene expression and can act inside the cell.
What is the significance of evolutionary conservation in signaling proteins?
It indicates that many signaling mechanisms are preserved across different animal species.
What is the effect of adrenergic receptor activation?
Increased heart rate, force of heart contractions, and relaxation of smooth muscle in airways.
What is the relationship between sensitivity and specificity in receptors?
Sensitivity relates to the high affinity of receptors for their ligands, while specificity relates to the
precise interaction between signal and receptor.
What happens during integration of receptor systems?
The system receives multiple signals and produces a unified response.
What is the role of acetylcholine in the autonomic nervous system?
It is the primary neurotransmitter in cholinergic pathways, promoting relaxation and restoration.
How do cells respond to external signals?
Through receptor-mediated processes that amplify, integrate, transmit, and end the signaling
response.
with complete solutions.
What is signal transduction?
The conversion of information into a chemical change that results in a cellular response.
What are G-Protein Coupled Receptors (GPCRs)?
The largest group of plasma membrane receptors that act through intracellular G proteins
activated by binding guanosine triphosphate (GTP).
What physiological effects are associated with sympathetic activation?
Increases heart rate, bronchodilation, and mobilizes energy reserves (fight or flight response).
What physiological effects are associated with parasympathetic activation?
Decreases heart rate, promotes relaxation and restoration (rest and digest response).
How do agonists and antagonists differ?
Agonists activate receptors and produce effects of the natural ligand, while antagonists block
receptor effects.
What is the role of phosphorylation in signaling?
Functions as a switch to toggle enzyme activities and create binding sites for other molecules.
What is signal amplification?
The process where one activated enzyme catalyzes the activation of many molecules of a second
enzyme, creating a cascading effect.
,What are the four general types of adrenergic receptors?
α1, α2, β1, and β2.
What is the primary role of the sympathetic nervous system?
Triggers the 'fight or flight' response.
What is desensitization in cell signaling?
When a cell becomes unresponsive to a signal due to continuous presence of that signal.
What is the significance of second messengers in GPCR signaling?
They mediate the cellular responses initiated by activated G proteins.
What is the effect of the drug Propranolol?
It acts as a beta-adrenergic antagonist, reducing heart rate and blood pressure.
What is the difference between cholinergic and adrenergic pathways?
Cholinergic pathways use acetylcholine, while adrenergic pathways use epinephrine and
norepinephrine.
What is the function of gated ion channels in signaling?
They are crucial for cell signaling processes and can be opened by membrane potential or ligand
binding.
What does specificity in receptor signaling refer to?
The precise molecular complementarity between the signal and receptor molecules.
What is the role of enzyme cascades in signaling?
, They amplify the signal by activating multiple enzymes in a sequence.
What is the impact of defective signaling proteins?
They can disrupt cell cycle regulation and potentially lead to tumor formation (cancer).
What is the role of intracellular hormones?
They often regulate gene expression and can act inside the cell.
What is the significance of evolutionary conservation in signaling proteins?
It indicates that many signaling mechanisms are preserved across different animal species.
What is the effect of adrenergic receptor activation?
Increased heart rate, force of heart contractions, and relaxation of smooth muscle in airways.
What is the relationship between sensitivity and specificity in receptors?
Sensitivity relates to the high affinity of receptors for their ligands, while specificity relates to the
precise interaction between signal and receptor.
What happens during integration of receptor systems?
The system receives multiple signals and produces a unified response.
What is the role of acetylcholine in the autonomic nervous system?
It is the primary neurotransmitter in cholinergic pathways, promoting relaxation and restoration.
How do cells respond to external signals?
Through receptor-mediated processes that amplify, integrate, transmit, and end the signaling
response.
