86 Questions
What is the main role of G protein βꝩ subunits in cellular signaling?
Promote signal amplification
In the GPCR-PIP2 pathway, which second messenger is associated with it?
DAG
What is the main function of Receptor Tyrosine Kinases (RTKs) in cellular signaling?
Transduce signals by phosphorylating tyrosine residues
Which type of receptors are gated ion channels (ionotropic receptors)?
Ligand-gated ion channels
What is the process described as receptor mediated endocytosis?
Cellular uptake of ligand-receptor complexes for signaling molecule degradation
What is the function of diacylglycerol (DAG) in cellular response to signal hormone binding?
Activates Protein Kinase C (PKC)
Which second messenger diffuses to the endoplasmic reticulum (ER) and opens specific Ca2+ channels upon hormone binding?
Inositol 1,4,5-trisphosphate (IP3)
How do rises in intracellular [Ca2+] affect cellular responses like contraction in muscles?
Stimulate cross-bridge cycling in muscles
What regulates the activity of many Ca2+-dependent enzymes/proteins by binding to Ca2+ at a certain threshold?
Calmodulin (CaM)
What is the role of kinases in cellular pathways according to the text?
Phosphorylation of proteins via covalent bonds
Which enzyme is activated by rises in intracellular [Ca2+] and subsequently stimulates cross-bridge cycling?
Myosin light chain kinase
What activates Protein Kinase A (PKA) according to the text?
Glucagon
Which molecule can move into the nucleus and phosphorylate CREB?
cAMP
How is Ca++ release triggered in the cell according to the text?
PKA activation
Which G protein subunit directly activates or inactivates ion channels in the plasma membrane?
β subunit
What specific membrane phospholipid is targeted by phospholipase C (PLC)?
PIP2
What physiological effect can be expected from GPCRs coupled to Gq proteins?
Stimulated smooth muscle contraction
What type of receptor is the Nicotinic acetylcholine (ACh) receptor?
Ligand-gated ion channel
Where do lipophilic signals carried by transport proteins in the blood plasma bind?
Intracellular receptors in the cytoplasm or nucleus
Which type of hormones bind to intracellular receptors that are transcription regulators?
Steroid hormones
What is essential for receptor-mediated endocytosis initiation?
Clathrin
What does the binding of ligands to intracellular receptor proteins alter?
The ability of these proteins to control gene transcription
What is the main outcome of the signal mediated by the Nicotinic acetylcholine (ACh) receptor?
Depolarization of membrane triggering muscle contraction
What is the main difference between Serine/Threonine Kinases and Tyrosine Kinases?
Serine/Threonine Kinases phosphorylate serine and threonine amino acids, while Tyrosine Kinases phosphorylate tyrosine amino acids.
How do Receptor Tyrosine Kinases (RTKs) transduce extracellular signals differently from G Protein-Coupled Receptors (GPCRs)?
RTKs autophosphorylate, while GPCRs rely on ligand binding for activation.
What is a major regulatory mechanism for the Insulin Receptor?
Receptor sequestration and downregulation.
What is the main function of excitable cells in response to external signals?
Regulate muscle contraction.
How are ion channels in excitable cells activated?
By binding of specific ligands.
Which type of receptors can modulate the phosphorylation state and be regulated by antagonist drugs?
Tyrosine Kinases
What is the main function of G protein βꝩ subunits in cellular signaling?
Inhibiting the activity of adenylate cyclase
Which second messenger is associated with the GPCR-PIP2 pathway?
Diacylglycerol (DAG)
What is the mechanism of action of Receptor Tyrosine Kinases (RTKs) in cellular signaling?
Activating downstream signaling pathways
What is the role of gated ion channels (ionotropic receptors) in cellular communication?
Directly activate intracellular signaling cascades
How do different second messengers like cAMP, Ca+2, DAG, and IP3 affect cellular responses?
Activate different downstream pathways
What type of signal molecules bind to intracellular receptors that are transcription regulators?
Steroid hormones
Which protein is essential for the initiation of receptor-mediated endocytosis?
Clathrin
What is the main function of intracellular receptors described in the text?
Control gene transcription
Which type of receptor is the Nicotinic acetylcholine (ACh) receptor based on its function?
Ligand-gated ion channel
What is the role of membrane-associated protein Clathrin in cellular signaling pathways?
Mediating endocytosis
How do small hydrophobic signal molecules enter target cells?
Diffusing directly across the plasma membrane
What effect does the rise in intracellular [Ca2+] have on Calmodulin (CaM)?
Ca2+ activates Calmodulin by causing a conformational change
How is Protein Kinase C (PKC) activated in combination with DAG?
Increase in intracellular [Ca2+]
What is the role of Calmodulin-dependent kinases?
Activate enzymes upon Ca2+ binding
How are rises in intracellular [Ca2+] handled in excitable cells?
Stimulate cross-bridge cycling in muscles
What triggers the release of stored Ca2+ to the cytosol from the ER?
[Ca2+] increase in the cytosol
How does IP3 affect the endoplasmic reticulum (ER) upon binding?
Opens specific Ca2+ channels
What is the main difference between Serine/Threonine Kinases and Tyrosine Kinases?
Serine/Threonine Kinases phosphorylate serine and threonine amino acid residues, while Tyrosine Kinases phosphorylate proteins on tyrosine residues.
What is the primary function of Protein Kinase A (PKA) as described in the text?
Activates enzymes involved in fat mobilization
What is the major regulatory mechanism for the Insulin Receptor?
Receptor sequestration and downregulation
Which molecule can move into the nucleus to phosphorylate CREB?
cAMP
In excitable cells, what determines their excitability?
Change in transmembrane electrical potential (voltage) or binding of specific ligands
How is Ca++ release triggered in the cell according to the text?
By activation of phospholipase C (PLC)
Which type of receptors can be modulated by antagonist drugs and regulate the phosphorylation state?
Receptor Tyrosine Kinases
What is the specific role of G proteins in cellular signaling, as mentioned in the text?
Activate or inactivate ion channels in the plasma membrane
What transduces extracellular signals differently between Receptor Tyrosine Kinases (RTKs) and G Protein-Coupled Receptors (GPCRs)?
Mechanism of signal transduction
What is the main second messenger associated with the GPCR-Gq protein pathway?
IP3
What is the key feature that distinguishes Tyrosine Kinases from Serine/Threonine Kinases?
Phosphorylation specificity
What distinguishes Serine/Threonine Kinases from Tyrosine Kinases?
The amino acids they phosphorylate in their targets
How do Receptor Tyrosine Kinases (RTKs) transduce extracellular signals differently from G Protein-Coupled Receptors (GPCRs)?
Through a different mechanism of signal transduction
What is a major regulatory mechanism for Receptor Tyrosine Kinases (RTKs) apart from receptor sequestration and downregulation?
Modulation of the phosphorylation state
What is the primary feature that allows certain excitable cells to respond to external signals?
Change in membrane potential using ion channels
What is the main regulatory mechanism for the Insulin Receptor specifically?
Receptor endocytosis and degradation
What is the primary function of ligand-gated ion channels in excitable cells?
Serving as a regulated path for movement of ions
What is the primary function of Protein Kinase A (PKA) in cellular signaling?
Phosphorylation of CREB leading to altered gene expression
How is calcium release triggered in the cell according to the provided information?
Through the cAMP pathway and activation of PKA
What can move into the nucleus and phosphorylate CREB?
PKA
What is the specific membrane phospholipid targeted by phospholipase C (PLC)?
PIP2
Which outcome is associated with G proteins coupled to Gq proteins?
Activation of phospholipase C (PLC)
What is the result of ligand-gated ion channel activation by G protein βꝩ subunits?
Depolarization of cells made easier
What is the primary function of cAMP in cellular signaling pathways?
Serving as a second messenger for several regulatory molecules
Which signaling pathway involves G protein βꝩ subunits?
GPCR cAMP pathway
How do Receptor Tyrosine Kinases (RTKs) differ from G Protein-Coupled Receptors (GPCRs) in signal transduction?
RTKs directly phosphorylate proteins, while GPCRs activate G proteins
In cellular signaling, what is the mechanism of action of intracellular receptors?
Directly regulating gene transcription after ligand binding
What is the role of receptor-mediated endocytosis in cellular communication?
Recycling of membrane receptors and ligand internalization
What is the main function of the Nicotinic acetylcholine (ACh) receptor?
Triggers depolarization of the membrane
How do lipophilic signal molecules typically enter target cells?
Through direct diffusion across the plasma membrane
What is the role of Clathrin in receptor-mediated endocytosis?
Essential protein for endocytosis initiation
Which type of receptors are transcription regulators in the cytoplasm or nucleus?
Intracellular receptors
What happens when ligands bind to intracellular receptor proteins?
They regulate specific gene expression
Which molecule is responsible for mediating the passage of an electrical signal at some synapses?
Nicotinic acetylcholine (ACh)
What is the role of IP3 in cellular signaling after binding to specific IP3-gated Ca2+ channels?
Induces the release of stored Ca2+ from the endoplasmic reticulum (ER)
What is the main function of Calmodulin (CaM) in response to changes in intracellular [Ca2+] levels?
Regulates Ca2+-dependent enzymes/proteins
In cellular signaling, what is the primary function of kinases?
Phosphorylate proteins via covalent bonds
What effect does a rise in intracellular [Ca2+] levels have on Calmodulin (CaM)?
Triggers a conformational change and binding to target proteins
Which process involves functional changes in target proteins like enzyme activity, cellular location, and association with other proteins?
Phosphorylation by kinases
What is the role of Gq protein activation in the GPCR-PIP2 pathway?
Increases cytosolic [Ca2+] levels
Test your knowledge on cellular communication in veterinary medicine including G protein βꝩ subunits, GPCR-PIP2 pathway, second messengers (cAMP, Ca+2, DAG, IP3), and receptor tyrosine kinases. This quiz is part of the Cellular Biology & Homeostasis course at Ross University School of Veterinary Medicine.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
