Exam 3: Ch 15 CLICKER Flashcards
Nitric Oxide gas released by endothelial cells in the blood vessels diffuses to induce relaxation of adjacent smooth muscle cells. This is an example of___________ signaling.
A. Endocrine
B. Paracrine
C. Synaptic
D. Contact-dependant
B. Paracrine
During nervous-system development in Drosophila, the membrane-bound
protein Delta acts as an inhibitory signal to prevent neighboring cells from developing into neuronal cells. Delta is involved in ______________ signaling.
A. Endocrine
B. Paracrine
C. Synaptic
D. Contact-dependent
D. Contact-dependent
If signaling molecules act on the same cells that release them, it is an example of _____________ signaling.
A. Endocrine
B. Autocrine
C. Synaptic
D. Contact-dependent
B. Autocrine
Monomeric GTPases are in “ON State(active)” upon binding to:
A. GDP
B. GTP
C. ADP
D. ATP
B. GTP
Which of these occur more rapidly in response to a signal?
A- Changes in protein phosphorylation
B- Changes in mRNA synthesis
A- Changes in protein phosphorylation
Which of these best describe the GPCRs?
A- All receptors of this class are polypeptides with seven transmembrane segments.
B- Alter the membrane potential directly by changing the permeability
of the plasma membrane.
C- Must be coupled with intracellular monomeric GTP-binding
proteins
A- All receptors of this class are polypeptides with seven transmembrane segments.
The length of time a G protein will signal is determined by _______.
A- the activity of phosphatases that turn off G proteins by dephosphorylating Gα.
B- the activity of protein phosphatases that turn GTP into GDP.
C- the GTPase activity of Gα.
C- the GTPase activity of Gα.
The two monomers in a receptor tyrosine kinase dimer phosphorylate each other and the process is called………………
A- Nucelotide exchange
B- Ubiquitination
C- Serine Phosphorylation
D- Trans-autophosphorylation
D- Trans-autophosphorylation
Which of the following mechanisms is not directly involved in inactivating an activated RTK (Receptor Tyrosine Kinase)?
A- dephosphorylation by serine/threonine phosphatases
B- dephosphorylation by protein tyrosine phosphatases
C- removal of the RTK from the plasma membrane by endocytosis
D- digestion of the RTK in lysosomes
A- dephosphorylation by serine/threonine phosphatases
Activation of Notch is irreversible?
A) TRUE
B) FALSE
A) TRUE
There is no fundamental chemical distinction between signaling molecules that bind to cell-surface receptors and those that bind to intracellular receptors.
A. True
B. False
False. There is a fundamental chemical distinction between signaling molecules that bind to cell-surface receptors and those that bind to intracellular receptors. Cell-surface receptors typically bind to hydrophilic signaling molecules, such as peptides, proteins, and most neurotransmitters, while intracellular receptors usually bind to hydrophobic signaling molecules, such as steroid hormones and thyroid hormones. This difference in chemical nature is due to the location of the receptors and the types of molecules they need to interact with for signaling.
What is the term for the protein that organizes groups of interacting intracellular signaling proteins into signaling complexes?
A. Intracellular receptor
B. Kinase cascade
C. Scaffold protein
D. Interaction domain
C. Scaffold protein
What is the term for the compact protein modules found in many intracellular signaling
molecules that bind to a particular structural motif in another protein (or lipid) molecule to
which the signaling protein binds?
A. Cell-surface receptors
B. Ligands
C. Interaction domains
D. Scaffold proteins
C. Interaction domains
Negative feedback counteracts the effect of a stimulus and thereby abbreviates and
limits the level of the response, making the system less sensitive to perturbations.
A. True
B. False
A. True
Alterations in signaling in the pituitary gland can lead to human disease. The GH-releasing
hormone (GHRH) stimulates release of growth hormone (GH) from the pituitary gland by binding to GHRH receptors, which are G-protein-coupled receptors. Excessive activity of the GHRH signaling leads to excessive release of growth hormone, which can lead to a form of gigantism.
Consider steps that could be taken to reduce GH release. Select if the following interventions indicated in blue below belong to A or B category.
*Block hydrolysis of GTP by G-alpha.
A. Decreases GH release
B. Increases GH release
B. Increases GH release
