Cell Signaling AP Biology Midterm Review

It contains the receptor for the signaling molecule

A cell is known to respond to a particular signaling molecule. Which of the following must be true of this cell? It is in the heart muscle It is also the site of production for the signaling molecule It contains the receptor for the signaling molecule It is incapable of signal transduction

Second amplify

Circle the correct answer - cAMP is an important molecule that is part of several signaling cascades. It is classified as a (first/second/third) messenger and it can (amplify/stop/suppress) the signal.

Epinephrine binds to a cell-surface receptor; the activated receptor stimulates production of second messenger, cAMP

Epinephrine is a protein hormone found in many animals. Epinephrine stimulates a signaling pathway that results in the breakdown of glycogen to glucose in the liver cells. Which of the following describes the initial steps in the process whereby epinephrine stimulates glycogen breakdown? a) Epinephrine binds to a cell-surface receptor; the activated receptor stimulates production of the second messenger, cAMP. b) Epinephrine binds to a cell-surface receptor; the activated receptor catalyzes the conversion of glycogen to glucose. c) Epinephrine diffuses through the plasma membrane; the hormone dimerizes in the cytosol. d) Epinephrine is taken into the cell by endocytosis; glycogen is converted to glucose in the endocytotic vesicle.

G protein, adenyl cyclase, cAMP, and protein kinase

Following activation of a receptor, which sequence below represents the correct order in which components will be involved in a signaling pathway that utilizes the second messenger cAMP? G protein → cAMP → adenyl cyclase → protein kinase G protein → adenyl cyclase → cAMP → protein kinase adenyl cyclase → cAMP → G protein → protein kinase cAMP → adenyl cyclase → protein kinase → G protein protein kinase → G protein → adenyl cyclase → cAMP

Activation of a protein kinase

Immediately following binding of a growth factor, an activated receptor would most likely stimulate activation of a protein kinase. activation of adenylyl cyclase. activation of a calcium-binding protein. activation of a protein phosphatase.

results in a conformational change in each phophorylated protein

In general, a signal transmitted via a phosphorylation cascade... is initiated by a phosphorylase enzyme. is propagated by a steroid receptor. results in a conformational change in each phosphorylated protein. is turned off by a kinase enzyme.

Target cells close to the cell from which it was secreted

In paracrine signaling, the signaling molecules affect only Target cells close to the cell from which it was secreted Target cells distant from its site of synthesis in cells of an endocrine organ Both (a) and (b) None of the above

All of the above

In the signal transduction mechanism known as protein phosphorylation... The signaling molecule binds to a surface receptor Receptor kinases play a key role in triggering the signal cascade Phosphorylated proteins act with enzymes to trigger the signal cascade All of the above

C A B

Listed below are events that occur during a signal transduction pathway. In which order do they occur? A. The plasma membrane receptor interacts with an effector protein. B. Second messenger molecules are released. C. Ligand binds to the plasma membrane receptor.

Paracrine

Many of the extracellular signal molecules that regulate inflammation are released locally at the site of infection. What form of cell-to-cell signaling is being used? Endocrine Paracrine Synaptic Neurotonal

Neurotransmitters

Simple nerve reflexes use signaling molecules called Nitric oxides Neurotransmitters G proteins Proteases

Increase in the concentration of certain intracellular signaling molecules called second messenger

The binding of ligands to many G-proteins linked receptors leads to shortlived Increase in the concentration of certain intracellular signaling molecules called second messenger Decrease in the concentration of certain intracellular signaling molecules called second messenger Increase in the concentration of certain extracellular signaling molecules called first messenger Decrease in the concentration of certain extracellular signaling molecules called first messenger

First messenger

The hormone or ligand can be considered as First messenger Second messenger Both (a) and (b) None of the above

To regulate gene expression

The primary function of transcription factors is... to regulate the conversion of ATP into cAMP. to regulate DNA synthesis. to regulate gene expression. to transmit signals from an activated receptor to intracellular G proteins.

Signaling molecule, target cell, receptors

When a ______________ reaches its ___________, there is a specific means of receiving it and acting on the message. This task is the responsibility of specialized proteins called _________. Signaling molecule; receptor; G proteins Signaling molecule; target cell; G proteins Signaling molecule; target cell; receptors Kinase; receptors; proteases

Signal molecule

When a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as which part of the signal pathway? receptor relay molecule signal molecule transducer molecule protein

Signal Transduction

When cells respond to an extracellular signal, they most often convert the information from one form to another. This process is called: Signal transformation Signal transduction Signal interference Signal amplification

Endocrine

When the hormone insulin is released into the bloodstream, what form of cell-to-cell signaling is being used? Endocrine Paracrine Synaptic Neurotonal

The receptor protein

Which molecule (or molecules) performs the primary signal transduction step in a signal transduction cascade? The extracellular signal The receptor protein The intracellular protein kinases The second messenger

All of these

Which of the following comes under the category of cell surface receptors? Enzyme linked receptors Ion-channel linked receptors G protein linked receptors All of these

The membrane receptor protein undergoes a conformational change.

Which of the following is the first event that occurs following the binding of a ligand by a membrane receptor protein? An intracellular enzyme is activated by phosphorylation. An intracellular G protein is activated. The membrane receptor protein undergoes a conformational change. The membrane receptor protein enters the cytoplasm.

They would be unable to grow and divide in response to growth factors from nearby cells.

Which of the following is the most likely fate of animal cells that lack receptors for local paracrine signal molecules? They would be unable to grow and divide in response to growth factors from nearby cells. They would be unable to respond to hormone signals delivered through the bloodstream. They would bind locally secreted growth factors, but intracellular signal pathways would be blocked. They would grow and divide normally.