Quiz 6,7,8 answers Flashcards
The choice that does not accurately describe Cytokine receptors
1. Can bind more than one kind of cytokine, even as many as 10 different cytokines
2. Can have long disordered regions ranging over 600 residues
3. transmembrane proteins with extracellular, intracellular and transmembrane regions
4. diverse number of extracellular domains
5. some have intracellular Ig domains
- some have intracellular Ig domains
If the common gamma chain acquired a mutation that inhibited PI3KAkt signaling, the cell would be more likely to__
1. undergo cell division
2. remain unaffected
3. survive
4. undergo apoptosis
5. lose transcriptional activity
- undergo apoptosis
cAMP is a second messenger that:
1. leads to phosphorylation of cytoplasmic and nuclear proteins by PKA
2. binds the catalytic domain of PKA
3. creates a membrane docking site for signaling proteins
4. is generated by adenylate cyclase by cyclizing 5’-AMP
5. activates adenylate cyclase
- leads to phosphorylation of cytoplasmic and nuclear proteins by PKA
Cytokines are proteins that
1. have diverse function, including one protein that can be either anti-inflammatory or pro-inflammatory
2. bind an extracellular receptor on only one specific type of cell, most of these cell types being in the immune system
3. have similar molecular weight and mostly helical structure
4. are rarely linked to disease but have been targeted for cancer and autoimmune treatment
- have diverse function, including one protein that can be either anti-inflammatory or pro-inflammatory
All below mechanisms contribute to termination of GPCR-mediated signal transduction EXCEPT:
1. B-arrestin binding to the GPCR
2. Exchange of GDP for GTP on Ga
3. Acceleration of GTPase activity by RGS proteins
4. Phosphorylation of the GPCR by GRK
5. Breakdown of cAMP by PDE
- Exchange of GDP for GTP on Ga
Cell surface receptors with seven transmembrane domains signal by
1. acting as GTPase
2. binding to and co-localizing several proteins
3. acting as a guanine nucleotide exchange factor
4. opening a calcium channel
5. tyrosine phosphorylation
- acting as a guanine nucleotide exchange factor
Which of the following enzymes phosphorylate licensing factors to initiate replication?
1. CDK2
2. Cyclin H
3. Cyclin A
4. Cdc6
5. CDC45
- CDK2
Gleevac (imatinib) treatment produces a prolonged remission (but not a cure) of most cases of CML. In all the responsive cases, the Abl tyrosine protein kinase activity in the cancer cells has been activated by
1. aberrant recombination that caused loss of the inhibitory domain from the catalytic domain
2. gene duplication
3. mutational activation of the activation loop
4. increased transcription
5. mutational activation of an upstream activating protein kinase
- aberrant recombination that caused loss of the inhibitory domain from the catalytic domain
Inositol tri-phosphate, IP3, is produced by which enzyme activity?
1. GTPase
2. tyrosine kinase
3. calmodulin
4. phospholipase C
5. adenylate cyclase
- phospholipase C
In Gq signaling, cytoplasmic calcium levels increase as a result of
1. phosphorylation of G-proteins
2. calcium pumps
3. binding of Gaq to adenylate cyclase
4. active transport driven by the high calcium concentration in the extracellular space
5. passive diffusion of calcium from the ER through gated channels
- passive diffusion of calcium from the ER through gated channels
What are the signaling receptors?
intracellular or integral membrane proteins
What are the cytokine receptors?
Immunoglobulin (Ig) family
Hemopoietic Growth Factor (type 1 and Type II) family
Interferon (type 2) family
Tumor Necrosis factors (TNF) (type 3) family
G protein-coupled receptors
Interleukin-17 receptor
What are some cytokine characteristics?
Pleiotropic- same cytokine can have different target cells and receptors, with different biological outcomes
redundancy- different cytokines produce same effects
What are the cytokine types?
interleukins
chemokines
TNF (Tumor Necrosis Factor)
Interferons
Which of the following is TRUE about the action of HDAC inhibitors?
1. They decrease nucleosome mobility
2. They (indirectly) promote transcription
3. They prevent DNA methylation
4. They (indirectly) reduce protein synthesis
5. They (indirectly) decrease histone acetylation
- They (indirectly) promote transcription
Human genes with recognizable TATA boxes are most likely to be
1. regulated in response to either physiological or developmental changes, but not both
2. pseudogenes
3. regulated in response to physiological and developmental changes
4. expressed at a constant rate; “housekeeping” genes
5. regulated by the cell cycle only
- expressed at a constant rate; “housekeeping” genes
Which of the following is a difference between lysosomal and ubiquitin-mediated protein degradation?
1. Lysosomal degradation occurs only in the nucleus, but ubiquitin-mediated protein degradation occurs only in cytoplasm
2. These two processes are synonymous
3. Lysosomal degradation is the degradation of organelles whereas all proteins are degraded through ubiquitin-dependent mechanisms
4. Proteases inside the lysosome mediate lysosomal degradation whereas the proteasome is responsible for ubiquitin-mediated protein degradation
5. Ubiquitin-mediated degradation is non-selective whereas lysosomal degradation is highly specific
- Proteases inside the lysosome mediate lysosomal degradation whereas the proteasome is responsible for ubiquitin-mediated protein degradation
Which statement correctly describes the 20S proteasome?
1. Requires phosphorylation for activation
2. Has three enzyme activities: trypsin, chymotrypsin, and caspase
3. recognizes and degrades ubiquinated proteins
4. Is only expressed in the ER
5. Degrades both correctly folded and misfolded proteins
- Has three enzyme activities: trypsin, chymotrypsin, and caspase
TFIIH is a critical factor for initiating transcription. Which of the following is NOT a function of TFIIH?
1. DNA binding
2. Kinase
3. Phosphatase
4. Helicase
5. ATPase
- Phosphatase
