Membrane Bound Receptors and Secondary Messengers quiz Flashcards
Membrane Bound Receptors and Secondary Messengers quiz
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Which of these acts as a second messenger?
Cyclic AMP (cAMP), DAG, and IP3 are examples of second messengers. What property prevents the ligands of cell-surface receptors from entering the cell?
The ligands of cell-surface receptors are typically hydrophilic, preventing them from crossing the hydrophobic cell membrane. Where do second messengers relay signals?
Second messengers relay signals inside the cell, often leading to a cascade of reactions that result in a cellular response. What is a second messenger?
A second messenger is a molecule that transmits signals from a receptor on the cell surface to target molecules inside the cell, amplifying the signal. What type of hormones bind to receptors located on the cell membrane?
Amino acid-based hormones bind to receptors located on the cell membrane. Where do DAG and IP3 originate?
DAG and IP3 originate from the cleavage of PIP2 by the enzyme phospholipase C. Which of these is a membrane receptor?
G protein-coupled receptors (GPCRs) are examples of membrane receptors. What type of hormones use second messengers in a cascade of reactions that trigger a cell response?
Amino acid-based hormones use second messengers in signaling cascades to trigger cellular responses. What can cause upregulation of a target cell's receptors?
Upregulation can occur in response to increased hormone levels or prolonged exposure to a hormone. What role do secondary messengers play in cell signaling?
Secondary messengers amplify the signal from the receptor and initiate a cascade of intracellular reactions leading to a cellular response. What is the function of tyrosine-kinase receptors?
Tyrosine-kinase receptors function by phosphorylating tyrosine residues on target proteins, initiating a signaling cascade. How does a nonsteroid hormone effect change in a target cell?
A nonsteroid hormone binds to a cell-surface receptor, activating a second messenger system that triggers a cellular response. What happens when a signaling molecule binds to a ligand-gated ion channel?
When a signaling molecule binds to a ligand-gated ion channel, it opens the channel, allowing ions to flow across the membrane and alter the cell's electrical state. Which kind of hormones require the use of secondary messengers?
Amino acid-based hormones require the use of secondary messengers for signal transduction. What second messenger stays in the membrane after cleavage of PIP2?
DAG remains in the membrane after the cleavage of PIP2. Which of the following correctly describes a second messenger? A) A molecule that binds to a receptor B) A molecule that amplifies a signal inside the cell C) A molecule that directly activates a hormone D) A molecule that inhibits cellular responses
B) A molecule that amplifies a signal inside the cell Once a GPCR is activated, what happens next?
Once a GPCR is activated, it activates a G protein, which then initiates a signaling cascade inside the cell. Where are the receptors for hydrophilic hormones located?
The receptors for hydrophilic hormones are located on the cell membrane. Which of the following are among the most common second messengers? A) ATP B) cAMP C) Calcium ions D) DAG E) IP3
B) cAMP, D) DAG, E) IP3 Which of the following does not require the release of a first messenger? A) Steroid hormone signaling B) Amino acid-based hormone signaling C) GPCR activation D) Tyrosine kinase receptor activation
A) Steroid hormone signaling What is the second messenger in the receptor tyrosine kinase signaling pathway?
Receptor tyrosine kinase pathways typically do not use second messengers like cAMP; they directly phosphorylate proteins. What second messenger most directly causes calcium ions to be released from intracellular stores?
IP3 most directly causes the release of calcium ions from intracellular stores. Where are peptide hormone receptors found?
Peptide hormone receptors are found on the cell membrane. Under what condition will a target cell always respond quickly to an extracellular signal?
A target cell will respond quickly if it has a high density of receptors for the specific extracellular signal. What type of receptor requires an effector protein to initiate a signal?
G protein-coupled receptors (GPCRs) require an effector protein, such as a G protein, to initiate a signal.
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