Following statements are regarding to receptor serine kinases.

A. The two serines in each Smad3 that were phosphorylated by the RI receptor kinase bind to phosphoserine-binding sites in the MH1 domains of a Smad3 or a Smad4, forming a stable complex containing two molecules of phosphorylated Smad3 (or Smad2) and one molecule of the co-Smad (Smad4).

B. The bound importin then mediates translocation of the heteromeric R-Smad/co-Smad complex into the nucleus.

C. After importin dissociates inside the nucleus, the Smad3/Smad4 (or Smad2/Smad4) complex binds to other transcription factors to activate transcription of specific target genes.

D. Transcription of the PAI-1 gene requires formation of a complex of the transcription factor TFE3 with the R-Smad/co-Smad (Smad3/Smad4) complex and binding of all these proteins to specific sequences within the regulatory region of the PAI-1 gene.

E. Within the nucleus, R-Smads are further modified by phosphorylation of their linker domains, monoubiquitinylation of their MH1 domains, acetylation of their MH2 domains, and dephosphorylation of the C-terminal serines by nuclear phosphatases.

Which of the following combination is incorrect?

#Question id: 10313

#Unit 6. System Physiology – Plant

Which of the following enzyme are found in the inner membrane of mitochondria?

#Question id: 10311

#Unit 6. System Physiology – Plant

A succinate dehydrogenase is one of the enzyme of TCA cycle, which is also known as Respiratory complex II. It is competitively inhibited by;

#Question id: 10310

#Unit 6. System Physiology – Plant

Which of the following enzyme in the kreb’s cycle function as an allosteric enzyme found in matrix space?

#Question id: 10309

#Unit 6. System Physiology – Plant

Which of the following carbon compound also called the oxoglutarate? 

#Question id: 10308

#Unit 6. System Physiology – Plant

Oxidative decarboxylation of pyruvate to acetyl-CoA by the PDH complex, how the pyruvate dehydrogenase complex carries out the five consecutive reactions in the decarboxylation and dehydrogenation of pyruvate?

 A) Pyruvate reacts with the bound thiamine pyrophosphate (TPP) of pyruvate dehydrogenase, undergoing decarboxylation to the hydroxyethyl derivative

 B) A transesterification in which the —SH group of CoA replaces the —SH group of E2 to yield acetyl-CoA and the fully reduced (dithiol) form of the lipoyl group

 C) The reduced FADH2 of E3 transfers a hydride ion to NAD1 , forming NADH, the enzyme complex is now ready for another catalytic cycle

 D) The transfer of two electrons and the acetyl group from TPP to the oxidized form of the lipoyllysyl group of the core enzyme, dihydrolipoyl transacetylase, to form the acetyl thioester of the reduced lipoyl group

 E) Dihydrolipoyl dehydrogenase promotes transfer of two hydrogen atoms from the reduced lipoyl groups of E2 to the FAD prosthetic group of E3 , restoring the oxidized form of the lipoyllysyl group of E2

 Find out the correct sequence of action of this complex enzyme?

#Question id: 10307

#Unit 6. System Physiology – Plant

pyruvate dehydrogenase (PDH) complex requires many enzymes for their functions, which of the following enzyme are not the part of this complex?