Untitled Flashcards Set
Question 1
1 / 1 pts
A GAP.......
stimulates the exchange of bound GDP for GTP.
Correct!
enhances the GTP hydrolysis rate of monomeric GTPases.
inhibits the GTPase actvity of monomeric GTPase.
is a factor without which monomeric GTPases cannot hydrolyze GTP.
Question 2
1 / 1 pts
An extracellular signal that is in the vicinity of the cell that secretes it and thereby activates signaling in the surrounding cells is classified as:
Correct!
paracrine signaling
endocrine signaling
autocrine signaling
synaptic signaling
Question 3
1 / 1 pts
Endocytosis of receptors followed by degradation in lysosomes in response to a signal is a mode of
receptor activation
positive feedback mechanism
Correct!
receptor desensitization
Question 4
1 / 1 pts
Which of these domains bind to proline-rich sequences?
Correct!
SH3 domain
PTB domain
PH domain
SH2 domain
Question 5
1 / 1 pts
Which of these is not a type of Receptor?
Ligand-gated ion channels
GPCRs
Enzyme-coupled receptors
Correct!
monomeric G proteins
Question 6
1 / 1 pts
Which of these responses to a signal are likely to occur in seconds?
Translation
Transcription
Correct!
Protein phosphorylation
Altered cell growth
Question 7
1 / 1 pts
Which of these statements is false?
Correct!
Phosphatases catalytically remove the phosphate from GTP in GTP-binding proteins.
Serine-specific kinases or threonine-specific kinases are common types of protein kinases.
For activation of GTP-binding proteins, the GDP is exchanged for GTP.
Question 8
1 / 1 pts
__________________ cells in select tissues release hormones that are distributed to the rest of the body.
Paracrine
Autocrine
Correct!
Endocrine
Local Mediators
Question 9
1 / 1 pts
Among which of these signaling mechanisms (other than endocrine signaling) do signaling molecules move farthest away from the cells that release them?
Correct!
Paracrine
Neuronal (synaptic)
Contact-dependent
Autocrine
Question 10
1 / 1 pts
Which of these are secreted extracellular signaling molecules that work only in the neighborhood they are released in?
Hormones
Correct!
Local mediators
Receptors
Question 11
1 / 1 pts
Electrical impulses sent along a neuronal axon reaches the synapse and triggers secretion of a chemical called...........
Correct!
Neurotransmitter
Nucleotides
Receptors
GTPases
Question 12
1 / 1 pts
Charged phosphoinositides are recognized and bound by
SH2 domains
Correct!
Pleckstrin Homology domain
SH3 domain
PTB domain
Question 13
1 / 1 pts
Scaffold proteins affect amplification and speed of signal by..................
Correct!
limiting amplification but improving speed.
enhancing amplification similar to diffusible messengers and enhacing speed.
limiting amplification and speed.
improving amplification similar to diffusible messengers but limiting speed.
Question 14
1 / 1 pts
Src Homology Domains (SH2) bind to which of these residues on activated receptors?
Serine
Arginine
Correct!
Phosphorylated Tyrosine
Ubiquitinated lysine
Question 15
1 / 1 pts
Activation of which of these proteins leads to the activation of a monomeric GTPase by releasing GDP and binding GTP.
Correct!
Guanine nucleotide exchange factor (GEF)
GTPase-activating protein (GAP)
Scaffold protein
Adaptor
Question 16
1 / 1 pts
Which of these enzymes phosphorylate a protein by transferring the terminal phosphate from ATP onto a serine, threonine or tyrosine residue?
Correct!
Kinase
Phosphatase
Monomeric GTPase
Ligase
Question 17
1 / 1 pts
A signaling molecule can generate a strong signaling response that persists even after the signaling molecule is removed and this can be due to:
Correct!
Positive feedback
Negative feedback
No feedback
Question 18
1 / 1 pts
Amplification of response to a signal can be generated when receptor activation leads to generation of a large number of intracellular signaling molecules/chemicals called................
kinases.
first messengers.
intracellular receptors.
Correct!
second messengers.