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Side ASide B
Using the yeast signal transduction pathways, both types of mating cells release the mating...
which induce changes in the cells that lead to cell fusion.
What is most likely to happen to an animal's target cells that lack receptors for local...
They might not be able to multiply in response to growth factors from nearby cells.
Which of the following is a likely explanation of why natural selection favored the evolution...
Even in the simplest organisms, sexual reproduction required several coordinated responses...
Which of the following is characterized by a cell releasing a signal molecule into the environment,...
paracrine signaling
In the formation of biofilms, such as those forming on unbrushed teeth, cell signaling serves...
aggregation of bacteria that can cause cavities
In yeast signal transduction, the yeast cells
secrete molecules that result in response by other yeast cells.
In which of the following ways do plant hormones differ from hormones in animals?
 Plant hormones may travel in air or through vascular systems.
In an experiment to track the movement of growth factor molecules from secretion to the point...
The growth factor is a paracrine signal.
When a neuron responds to a particular neurotransmitter by opening gated ion channels, the...
signal molecule
Of the following, a receptor protein in a membrane that recognizes a chemical signal is most...
the active site of an allosteric enzyme that binds to a specific substrate.
Which of the following is true for the signaling system in an animal cell that lacks the ability...
It would not be able to activate and inactivate the G protein on the cytoplasmic side of the...
Testosterone functions inside a cell by
binding with a receptor protein that enters the nucleus and activates specific genes.
Which of the following is true of transcription factors?
They control gene expression.
One of the major categories of receptors in the plasma membrane reacts by forming dimers, adding...
receptor tyrosine kinases
Because most receptors are membrane proteins, which of the following is usually true?
They change their conformation after binding with signal polypeptides.
Since steroid receptors are located intracellularly, which of the following is true?
The steroid/receptor complex can cross the nuclear membrane.
Receptor tyrosine kinases (RTKs) are found at high levels on various cancer cells. A protein,...
If the patient's cancer cells have detectable HER2.
The receptors for a group of signaling molecules known as growth factors are often
receptor tyrosine kinases.
In general, a signal transmitted via phosphorylation of a series of proteins
 brings a conformational change to each protein.
Sutherland discovered that epinephrine signals
elevation of cytosolic concentrations of cyclic AMP.
Which of the following is the best explanation for the inability of a specific animal cell...
insufficient ATP levels in the cytoplasm
The toxin of Vibrio cholerae causes profuse diarrhea because it
modifies a G protein involved in regulating salt and water secretion.
Which of the following would be inhibited by a drug that specifically blocks the addition of...
receptor tyrosine kinase activity
Which of the following most likely would be an immediate result of growth factor binding to...
protein kinase activity
 An inhibitor of phosphodiesterase activity would have which of the following effects?
prolong the effect of epinephrine by maintaining elevated cAMP levels in the cytoplasm
Adenylyl cyclase has the opposite effect of which of the following?
Caffeine is an inhibitor of phosphodiesterase. Therefore, the cells of a person who has recently...
If a pharmaceutical company wished to design a drug to maintain low blood sugar levels, one...
to block G protein activity in liver cells.
If a pharmaceutical company wished to design a drug to maintain low blood sugar levels, one...
that increases phosphodiesterase activity.
An inhibitor of which of the following could be used to block the release of calcium from the...
phospholipase C
Which of the following statements is true of signal molecules?
Protein kinase A activation is one possible result of signal molecules binding to G protein-coupled...
Which of the following is a correct association?
GTPase activity and hydrolysis of GTP to GDP
One inhibitor of cGMP is Viagra. It provides a signal that leads to dilation of blood vessels...
hydrolyzed cGMP to GMP
Which of the following is the best explanation for the fact that most transduction pathways...
Multiple steps provide for greater possible amplification of a signal.
Which of the following amino acids are most frequently phosphorylated by protein kinases in...
serine and threonine
The function of phosphatases in signal transduction is best described as to
inactivate protein kinases and turn off the signal transduction.
What explains the increased concentration of Ca++ in the ER?
 Calcium ions are actively imported from the cytoplasm into the ER.
In which of the following ways could signal transduction most probably be explored in research...
alteration of protein kinases in cell cycle regulation in order to slow cancer growth
A drug designed to inhibit the response of cells to testosterone would almost certainly result...
a decrease in transcriptional activity of certain genes
At puberty, an adolescent female body changes in both structure and function of several organ...
Estrogen binds to specific receptors inside many kinds of cells, each of which have different...
What are scaffolding proteins?
large molecules to which several relay proteins attach to facilitate cascade effects
The termination phase of cell signaling requires which of the following?
incompatibility of the binding of the signal molecule to the receptor
GTPase activity is involved in the regulation of signal transduction because it
hydrolyzes GTP binding to G protein.
Why has C. elegans proven to be a useful model for understanding apoptosis?
The nematode undergoes a fixed and easy-to-visualize number of apoptotic events during its...
Which of the following describes the events of apoptosis?
Its DNA and organelles are fragmented, the cell shrinks and forms blebs, and the cell self-digests.
If an adult person has a faulty version of the human analog to ced-4 of the nematode,...
a form of cancer in which there is insufficient apoptosis
Why is apoptosis potentially threatening to the healthy "neighbors" of a dying cell?
Lysosomal enzymes exiting the dying cell would damage surrounding cells.
In C. elegans, ced-9 prevents apoptosis in a normal cell in which of the...
It prevents the caspase activity of ced-3 and ced-4.
In research on aging (both cellular aging and organismal aging), it has been found that aged...
Growth factor ligands do not bind as efficiently to receptors.
Where do apoptotic signals come from?
all of the above
The human population's life expectancy has increased significantly but seems to have an...
an increase in the total population of humans on the planet
Which of the following types of signaling is represented in the figure?
In the figure, the dots in the space between the two structures represent which of the following?
Where would you expect to find the carboxyl end?
at the cytosol surface
) The coupled G protein most likely interacts with this receptor
at the loop between H5 and H6.
If you wish to design an experiment to block the G protein-coupled receptor interaction, the...
the amino acid sequence in the binding site for the G protein
When an excess of the ligand (hormone) is poured through the column after the receptor binding...
The ligand will cause the receptor to be displaced from the beads and eluted out.
This method of affinity chromatography would be expected to collect which of the following?
molecules of purified receptor
The description above illustrates which of the following?
Just because a drug acts on one type of receptor does not mean that it will act on another...
The use of beta 2 antagonist drugs may be useful in asthma because they may
dilate the bronchioles by relaxing their smooth muscle.
Beta 2 antagonist drugs might also be used most effectively for which of the following?
increasing low blood pressure
Phosphorylation cascades involving a series of protein kinases are useful for cellular signal...
they amplify the original signal manyfold.
Binding of a signaling molecule to which type of receptor leads directly to a change in the...
ligand-gated ion channel
The activation of receptor tyrosine kinases is characterized by
dimerization and phosphorylation.
Lipid-soluble signaling molecules, such as testosterone, cross the membranes of all cells but...
intracellular receptors are present only in target cells.
Consider this pathway: epinephrine → G protein-coupled receptor → G protein →...
Apoptosis involves all but which of the following?
lysis of the cell
Which observation suggested to Sutherland the involvement of a second messenger in epinephrine's...
Glycogen breakdown was observed only when epinephrine was administered to intact cells.
Protein phosphorylation is commonly involved with all of the following except
activation of G protein-coupled receptors.

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