86 Questions
What is the primary function of connexons?
To allow ions and small molecules to diffuse between cells
What is the term for the process by which a signaling molecule binds to a receptor, triggering a response in the target cell?
Signal transduction
What type of extracellular messenger is secreted by an endocrine cell into the interstitial fluid and then carried by the blood to distant target cells?
Hormone
What is the term for a type of extracellular messenger that acts on neighboring cells?
Paracrine
What is the term for the electrical signal that can trigger an action potential in a postsynaptic neuron?
Graded potential
What is the term for the type of signaling that involves the direct exchange of ions and small molecules between adjacent cells?
Cell-to-cell signaling
What is the primary function of an antagonist?
To bind to and block a receptor
Where are lipid-soluble extracellular messengers likely to bind to their receptors?
Inside the target cell (cytosol or nucleus)
What is the term for the process by which the number of receptors is increased or decreased in response to various stimuli?
Receptor regulation
What is the role of a second messenger in a signaling pathway?
To bind to and activate the next relay protein
What is the primary function of a protein kinase in a signaling pathway?
To phosphorylate a target protein
What is the term for the sequence of events between the binding of an extracellular messenger to a receptor and the cellular response?
Signal transduction pathway
What is the primary function of local mediators released from cells into interstitial fluid?
To act locally on neighboring or same cells
What is the role of thromboxanes in the body?
To constrict blood vessels and promote platelet aggregation
What is the term for the junction between a neuron and its target cell?
Synapse
What is the function of transport proteins in the bloodstream?
To increase the solubility of lipid-soluble hormones in blood
What is the characteristic of receptor binding that refers to the maximum amount of signal molecule that can bind to a receptor?
Saturation
What type of hormone is norepinephrine?
Amine hormone
What is the primary function of a G-protein in cell signaling?
To act as a relay protein and activate the rest of the pathway
Which type of molecules can easily permeate through the plasma membrane?
Non-polar molecules and steroids
What is the primary difference between the inner and outer surfaces of the plasma membrane?
The inner surface is more negatively charged
What is the combined influence of concentration and electrical gradients on an ion?
Electrochemical gradient
What type of proteins seal off passageways between adjacent cells?
Tight junctions
What is the primary function of adherens junctions?
To facilitate cell-to-cell adhesion
What is the primary function of adhesion belts in epithelial cells?
To resist separations during contractive activities
What type of filaments do desmosomes connect to?
Intermediate filaments made of keratin
What is the primary function of hemidesmosomes?
To anchor cells to the basement membrane
What is the primary function of integrins?
To anchor cells to the basement membrane
What is the primary function of gap junctions?
To facilitate communication between neighboring cells
What is the term for cells that are connected through gap junctions and can communicate through the exchange of ions and small molecules?
Electrically coupled
What is the primary function of ATP in cellular metabolism?
To generate energy for the body through phosphorylation
What is the purpose of substrate-level phosphorylation and oxidative phosphorylation in cellular metabolism?
To generate ATP through the energy released from catabolic reactions
What is the role of flavoprotein, cytochrome, and coenzyme Q10 in the electron transport chain?
To facilitate the transfer of electrons during oxidative phosphorylation
What is the primary function of enzyme-substrate interaction in cellular metabolism?
To catalyze chemical reactions by lowering the activation energy
What is the role of competitive inhibitors in enzyme-substrate interactions?
To decrease the rate of enzyme-catalyzed reactions
What is the primary function of gap junctions in cell signaling?
To facilitate the exchange of ions and small molecules between adjacent cells
What is the primary function of cell-to-cell binding in cell signaling?
To facilitate cell-to-cell communication through adhesion molecules
What is the primary function of cofactors in enzyme-substrate interactions?
To help enzymes form the correct shape to bind to substrates
Which of the following is an example of a local mediator that is synthesized when membrane phospholipid is cleaved to produce a 20-Carbon Fatty acid?
Eicosanoids
What is the function of transport proteins in the bloodstream?
To increase the solubility of lipid-soluble hormones in blood
What is the term for the small space that separates the pre and postsynaptic neurons, filled with interstitial fluid?
Synaptic cleft
What is the function of a receptor in a signaling pathway?
To detect the signal molecule and initiate the signal process
What is the term for the type of extracellular messenger that stimulates chemotaxis of leukocytes and mediates inflammation?
Leukotrienes
What is the characteristic of receptor binding that refers to the maximum amount of signal molecule that can bind to a receptor?
Saturation
What is the term for the junction between a neuron and its target cell?
Synapse
What is the function of thromboxanes in the body?
To constrict blood vessels and promote platelet aggregation
What is the primary function of a receptor agonist?
To bind to and activate a receptor, mimicking the action of an endogenous messenger
What is the primary mechanism by which ions and small molecules can diffuse from the cytosol of one cell to another?
Through connexons
Which of the following types of extracellular chemical messengers is responsible for communication between neurons?
Neurotransmitters
What is the location of receptors that bind to lipid-soluble ECM?
Inside the target cell, in the cytosol or nucleus
What is the term for the process by which the number of receptors is increased in response to various stimuli?
Up-regulation
What is the term for the combined effect of multiple graded potentials on a postsynaptic neuron?
Summation
What is the role of a protein kinase in a signaling pathway?
To phosphorylate a target protein
What is the primary difference between hormones and neurotransmitters?
Hormones are released from endocrine cells, while neurotransmitters are released from neurons
What is the term for the process by which a signal is transmitted from the presynaptic neuron to the postsynaptic neuron?
Synaptic signaling
What is the sequence of events that occurs after an ECM binds to a receptor?
Receptor binding, generation of an intracellular messenger, and signal transduction
Which of the following is an example of local signaling?
Paracrine signaling
What is the role of an intracellular messenger in a signaling pathway?
To mediate the transduction process
What is the primary function of the receptor in the signal transduction pathway?
To bind to the extracellular messenger
What is the term for the relay proteins that convey a signal between a receptor and an effector protein?
Relay proteins
What is the primary function of a receptor antagonist?
To bind to and block a receptor
What is the term for the type of cell-to-cell signaling that involves the direct exchange of ions and small molecules between adjacent cells?
Gap junction signaling
What is the primary function of G-protein in cell signaling?
To facilitate the binding of signaling molecules to receptors
What type of molecules can easily permeate through the plasma membrane?
Non-polar molecules
What is the primary function of tight junctions?
To seal off passageways between adjacent cells
What is the term for the difference in electrical charges between two regions?
Electrical gradient
What is the primary function of adherens junctions?
To regulate the adhesion of cells to each other
What is the primary function of the lipid bilayer in the plasma membrane?
To control the permeability of the plasma membrane
What is the term for the combined influence of concentration and electrical gradients on an ion?
Electrochemical gradient
What is the primary function of transmembrane proteins in the plasma membrane?
To control the permeability of the plasma membrane
What is the effect of up-regulation of receptors on a target cell?
The target cell becomes more sensitive to the messenger
What type of receptor is phenylephrine an agonist of?
Alpha-1 receptor
What is the role of a second messenger in a signaling pathway?
To generate an intracellular response
What is the effect of down-regulation of receptors on a target cell?
The target cell becomes less sensitive to the messenger
What type of receptor is Propranolol an antagonist of?
Beta receptor
Where are the receptors for lipid-soluble ECM located?
Cytosol or nucleus
What is the primary function of cellular respiration?
To generate energy for the cell
Which type of reaction releases more energy than it absorbs?
Exergonic reaction
What is the role of ATP in cellular metabolism?
To generate energy for the cell
What is the purpose of substrate-level phosphorylation and oxidative phosphorylation?
To generate ATP
What is the role of flavoprotein, cytochrome, and coenzyme Q10 in the electron transport chain?
To facilitate electron transport
What is the primary function of enzyme-substrate interaction in cellular metabolism?
To facilitate chemical reactions
What is the role of competitive inhibitors in enzyme-substrate interactions?
To inhibit enzyme activity
What is the primary function of cofactors in enzyme-substrate interactions?
To facilitate enzyme activity
What is the term for the process by which lactic acid, certain amino acids, and the glycerol part of triglycerides can be converted to glucose in the liver?
Gluconeogenesis
What is the primary function of gap junctions in cell signaling?
To facilitate cell-to-cell communication
This quiz covers cell communication and signaling mechanisms, including gap junctions, cell-to-cell binding, and extracellular chemical messengers such as hormones and neurotransmitters.
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