#Question id: 1257
#Unit 4. Cell Communication and Cell Signaling
Following statements are regarding to protein kinase A which phosphorylates multiple intracellular target proteins expressed in different cell types.
A. Inactive PKA is a tetramer consisting of two regulatory (R) subunits and two catalytic (C) subunits.
B. Each R subunit contains a pseudo-substrate domain whose sequence resembles that of a peptide substrate and binds to the active site in the catalytic domain but is not phosphorylated; thus the pseudo-substrate domain inhibits the activity of the catalytic subunits.
C. active PKA is turned off by binding of cAMP Each R subunit has two distinct cAMP-binding sites, called CNB-A and CNB-B.
D. Binding of cAMP by an R subunit of PKA occurs in a cooperative fashion; that is, binding of the first cAMP molecule to CNB-B increases the Kd for binding of the second cAMP to CNB-A. Thus small changes in the level of cytosolic cAMP can cause proportionately large changes in the number of dissociated C subunits and, hence, in cellular kinase activity.
Which of the following statements are incorrect?
#Question id: 16777
#Unit 13. Methods in Biology
What is the formula for the median of Grouped data?
#Question id: 683
#Unit 1. Molecules and their Interaction Relevant to Biology
Which factor does not help to explain why many proteins exhibit quaternary structure?
#Question id: 10942
#Unit 7. System Physiology – Animal
A 45-year-old man presents to the emergency room with a 2-week history of diarrhea that has gotten progressively worse over the last several days. He has minimal urine output and is admitted to the hospital for dehydration. His stool specimen is positive for parasitic eggs. Which type of WBCs would have an elevated number?
#Question id: 27384
#Unit 1. Molecules and their Interaction Relevant to Biology
The greater the effective nuclear charge on the atom