This set of Biochemistry Multiple Choice Questions & Answers (MCQs) focuses on “Multivalent Scaffold Proteins and Membrane Rafts”.
1. The specificity of signaling pathways does not include ___________
a) Migration of signal proteins into membrane rafts
b) Assembly of large multiprotein complexes
c) Phosphorylation of target proteins at Ser, Thr/Tyr residues
d) Flippase-catalyzed movement of phospholipids from the inner to the outer leaflet
Explanation: The specificity of signaling pathways does not include flippase-catalyzed movement of phospholipids from the inner to the outer leaflet.
2. Which of the following directly phosphorylate tyrosines to start a kinase protein enzymatic cascade?
a) Receptor tyrosine kinase
b) Receptor guanylyl cyclases
c) Receptor serine kinase
d) Receptor threonine kinase
Explanation: Only receptor tyrosine kinase directly phosphorylates tyrosine to start a kinase protein enzymatic cascade.
3. PTB domains bind to ___________
a) Phosphorylated tyrosine
b) Phosphoryated threonine
c) Phosphorylated serine
d) Phosphorylated cysteine
Explanation: Phosphotyrosine binding domain binds to phosphotyrosine.
4. Scaffold protein in insulin signal transduction ___________
Explanation: IRS-1 is an adapter protein in insulin that codes for IRS1 gene.
5. Which of the following is involved in extrinsic cell death pathway?
a) Heterotrimeric G protein complex
d) Protein-kinase A
Explanation: TRADD, tumor necrosis factor receptor type 1-associated death domain protein is involved in extrinsic cell death pathway.
6. Which of the following converts GTP to cGMP to start its enzymatic cascade?
a) Receptor guanylyl cyclase
b) Receptor adenylyl cyclase
d) Protein kinase-A
Explanation: Receptor adenylyl cyclase converts ATP to cAMP.
7. Which of the following are stimulated to become membrane associated upon binding of insulin to the insulin receptor?
Explanation: PH domain is stimulated to become membrane associated upon binding of insulin to the insulin receptor.
8. Which of the following is involved in phospho-tyrosine binding?
Explanation: SH3 is involved in proline rich motif binding.
9. Which of the following is involved in proline rich motif binding?
Explanation: SH2 is involved in phospho-tyrosine binding.
10. Which of the following is not a downstream component?
Explanation: Ras, MEK and ERK are the downstream components.
Sanfoundry Global Education & Learning Series – Biochemistry.
To practice all areas of Biochemistry, here is complete set of 1000+ Multiple Choice Questions and Answers.