57 Questions
What type of receptors are lipid soluble hormones like testosterone and estrogen bound to?
Nuclear receptors
How many times do G-protein coupled receptors (GPCRs) pass through the plasma membrane?
7 times
What molecular switches determine whether a G-protein is on or off?
GTP or GDP
At rest, what is the state of the G-protein and the enzyme in the GPCR pathway?
G-protein is bound to GDP, enzyme is inactive
What happens when a ligand binds to the GPCR?
The G-protein binds to the receptor and GTP displaces GDP, but the enzyme remains inactive
Which of the following statements about GPCRs is true?
They are associated with many diseases and have been targeted by about one-third of modern drugs
What is the primary role of cell signaling?
To allow cells to respond to their environment and other cells
Which of the following is an example of a local signaling molecule?
Fibroblast growth factor (FGF)
What is the primary function of the transduction step in cell signaling?
To amplify the signal through a cascade of molecular interactions
Which of the following is an example of a long-distance signaling molecule?
Insulin
What is the role of second messengers in cell signaling?
They amplify and propagate the signal within the cell
Which of the following is a common mechanism for receptor activation during cell signaling?
Phosphorylation of the receptor protein
Which of the following is NOT a reason why cells communicate?
To facilitate cellular division and growth
What is the overall method of cell signaling?
Cells release signaling molecules that bind to specific receptors on target cells
What is the role of a phosphorylation cascade in cell signaling?
To amplify the signal by activating multiple enzymes in a sequential manner
Which of the following is NOT a major cell surface receptor involved in cell signaling?
Nuclear receptors
Which of the following is NOT a major secondary messenger involved in cell signaling?
Adenosine triphosphate (ATP)
Which of the following is an example of a cellular activity that can be an output of cell signaling?
All of the above
What is the role of ACE2 in the context of SARS-CoV-2 infection?
It is the cellular receptor for the virus' spike protein
Which of the following best describes the analogy used to explain the interaction between ACE2 and the SARS-CoV-2 spike protein?
ACE2 is the lock, and the spike protein is the key
What is the primary function of the SARS-CoV-2 spike protein?
To facilitate viral entry into host cells
What is the function of neurotransmitters in signal transduction?
They bind to ion channels on target cells to propagate action potentials
What is the role of protein kinases in signal transduction pathways?
They transfer phosphate groups from ATP to specific proteins, typically activating them
Which amino acid residues are commonly phosphorylated in signal transduction pathways?
Serine and threonine
What is the function of second messengers in signal transduction pathways?
They are small molecules included in the signaling cascade to relay signals
In the cAMP signaling pathway, what is the role of adenylyl cyclase?
It converts ATP to cAMP, which acts as a second messenger
What is the effect of cholera toxin on the cAMP signaling pathway?
It disrupts the pathway by constitutively activating adenylyl cyclase
What is the main role of protein kinases in signal transduction pathways?
Adding phosphates to proteins, activating them
How do phosphatases contribute to signal transduction pathways?
Remove phosphates from proteins, rendering them inactive
Which group of residues are typically phosphorylated in signal transduction pathways?
Serine or threonine residues
What is the function of adenylyl cyclase in the cAMP signaling pathway?
Converts ATP to cAMP as a second messenger
Why could mutations affecting serine or threonine residues be detrimental in signal transduction pathways?
They interfere with the activation of downstream proteins
Which enzyme terminates the effect of protein kinases in signal transduction pathways?
Phosphatases
What is the primary reason for cells to communicate with each other?
To coordinate their activities and behavior
Which of the following is NOT a major cell surface receptor involved in cell signaling?
Steroid hormone receptors
What is the role of a phosphorylation cascade in cell signaling?
To amplify the signal and activate multiple downstream targets
Which of the following is a major secondary messenger involved in cell signaling?
Cyclic AMP (cAMP)
What is the primary function of the transduction step in cell signaling?
To transmit the signal from the extracellular environment to the cell interior
Which of the following is a common mechanism for receptor activation during cell signaling?
Conformational change in the receptor
What is the significance of the GTPase activity in G protein-coupled receptors (GPCRs)?
It promotes the release of the G protein from the enzyme, reverting it to the resting state.
What is the primary function of ligand-gated ion channels?
To regulate the flow of specific ions across the cell membrane in response to ligand binding.
Which of the following statements best describes the relationship between ligands and receptors?
Ligands are molecules that bind specifically to receptors, eliciting a response.
What is the primary function of ion channels in the context of cell signaling?
To regulate the flow of specific ions across the cell membrane.
Which body system heavily relies on ligand-gated ion channels?
Nervous system
What is the primary function of the GTP hydrolysis step in the G protein-coupled receptor (GPCR) signaling pathway?
To terminate the signaling cascade and return the system to the resting state.
What is the primary role of phosphodiesterase (PDE) in the context of cell signaling?
To degrade cAMP, thus terminating the signal
In the example of adrenalin stimulation of glycogen breakdown, what is the function of the phosphorylation cascade?
To amplify the signal, resulting in many glucose molecules produced
What is the primary purpose of the rapid breakdown of glycogen in response to adrenalin?
To provide energy for the body in a fight-or-flight situation
What is the role of caffeine in the context of the cAMP signaling pathway?
To inhibit the action of phosphodiesterase (PDE)
What is the primary function of the glucose 1-phosphate produced from glycogen breakdown?
To be converted to glucose 6-phosphate for use in glycolysis
What is the purpose of the amplification step in the adrenalin-stimulated glycogen breakdown pathway?
To generate a large amount of energy rapidly
What is the primary function of the reception step in cell signaling?
To initiate the binding of a signaling molecule to a receptor protein
Which of the following is an example of a long-distance signaling molecule?
Insulin
What is the primary role of the transduction step in cell signaling?
To amplify the signal by activating a relay of proteins
Which of the following is a characteristic of local signaling molecules?
They can act on the signaling cell itself (autocrine signaling)
What is the primary function of second messengers in cell signaling?
To relay and amplify the signal within the cell
Which of the following is a common mechanism for receptor activation during cell signaling?
Conformational change in the receptor protein
Learn about the Tyrosine Kinase Receptor and the JAK STAT pathway for BIOSCI 107 Class. Alexandria, the class representative, provides valuable information for Health Science students in the pre-med course. Get insights on important biological concepts.
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