30 Questions
Which of the following is NOT considered a chemical messenger in cellular communication?
Light
What is the role of cell surface receptors in cellular communication?
Receive and process external signals
Which of the following is an example of a hydrophobic messenger in cellular communication?
Steroid hormones
What is the purpose of intracellular signaling pathways in cellular communication?
Ensure tight control of cell response
Which of the following is a mechanism by which cells can directly communicate?
Interaction of a receptor with a ligand
What is the function of second messengers in cell signaling?
To amplify signals
Which of the following is an example of a second messenger cascade?
Increased intracellular concentration of cAMP
How do ligands that activate the same signaling pathways in cells usually produce the same effect?
By interacting with distinct receptors
Which of the following is NOT one of the three ways intercellular communication can occur?
Intracrine
What is the role of acetylcholinesterase in paracrine signaling at the neuromuscular junction?
It degrades the neurotransmitter acetylcholine
Which of the following is NOT a type of extracellular signaling molecule?
Nucleotides
What are effectors in signal transduction?
Proteins that initiate a cellular response
Which type of receptor is involved in signaling between electrically excitable cells and results in transient opening of the channel when a neurotransmitter binds to it?
Ligand-gated ion channels
Which type of receptor works indirectly through an intermediary called a G protein to activate or inactivate a separate membrane-associated enzyme or channel?
G protein-coupled receptors
Which type of receptor, when activated by a ligand, can either be enzymes themselves or part of an enzymatic complex?
Catalytic receptors
Which type of receptor, located in the cytosol or nucleus, is ligand-activated and links extracellular signals to gene transcription?
Nuclear receptors
Which of the following is NOT a consequence of ligand binding to a receptor?
Inhibition of protein kinases
What is the role of gap junctions in cell-to-cell communication?
Facilitate the passage of inorganic ions and small molecules
Which of the following is true about adhering junctions?
They provide important clues for the maintenance of normal cell architecture
What is the role of tight junctions in the diffusion barrier?
They stabilize the complex and have a signaling role
Which of the following is a characteristic of ligand-gated ion channels?
They are activated by binding of the signaling molecule to the receptor
What is the function of G proteins in signal transduction?
They mediate cellular responses to a diverse array of signaling molecules
What is the structure of G protein-coupled receptors (GPCRs)?
They consist of a single polypeptide chain with seven membrane-spanning α-helical segments
Which of the following is a characteristic of heterotrimeric G proteins?
They interact with downstream effector proteins such as adenylyl cyclase
Which subunits of the βγ complex are involved in anchoring the complex to the membrane?
α and γ
What holds the α subunit to the membrane?
A myristyl or a palmitoyl group
What holds the γ subunit to the membrane?
A prenyl group
How many combinations of the known α, β, and γ subunits are there?
Several hundred
What do G proteins link together?
Receptors and effectors
What are the multiple classes of G proteins suited for?
Linking receptors to effectors
Test your knowledge on signal transduction pathways and their effects on gene transcription with this quiz! Learn about the differences between genomic and nongenomic effects and explore the fascinating world of cell signaling.
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