The kinase activity of ATM is activated in response to DNA damage due to various stresses (e.g., UV irradiation, heat). Activated ATM then triggers following pathways leading to arrest in G1.

A. Chk2 is phosphorylated and, in turn, phosphorylates Cdc25A, thereby marking it for degradation and blocking its role in CDK2 activation.

B. Phosphorylation of p53 stabilizes it, permitting p53-activated expression of genes encoding proteins that cause arrest in G1, promote apoptosis, or participate in DNA repair.

C. Controlling the pool of p53, ATM phosphorylates MDM2 to inactivate it, causing increased stabilization of p53. Another protein p14ARF inhibits the activity of Mdm2 thus stabilizing p53.

Based on the above information, which one of the following statements is correct?

#Question id: 10305

#Unit 6. System Physiology – Plant

Pyruvate dehydrogenase complex Consists of three Distinct enzymes and it requires Coenzymes, these are;

#Question id: 10306

#Unit 6. System Physiology – Plant

pyruvate dehydrogenase (PDH) complex requires five different coenzymes or prosthetic groups and these enzymesalso require four different vitamins in human nutrition are vital components of this system:

#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?

#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: 10309

#Unit 6. System Physiology – Plant

Which of the following carbon compound also called the oxoglutarate? 

#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?