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TLS Online TPP Program

#Question id: 10308

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?

#Unit 1. Molecules and their Interaction Relevant to Biology
  1. E→C→B→E→D
  2. A→D→B→E→C
  3. E→B→D→A→C
  4. D→A→E→B→C
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TLS Online TPP Program

#Question id: 11549

#Unit 7. System Physiology – Animal

If a biochemist discovers a new molecule, which of the following pieces of data would allow her to draw the conclusion that the molecule is a steroid hormone?

I) The molecule is lipid soluble.

II) The molecule is derived from a series of steps beginning with cholesterol.

III) The molecule acts at a target tissue some distance from where it is produced.

IV) The molecule uses a transport protein when in an aqueous solution such as blood.
TLS Online TPP Program

#Question id: 1004

#Unit 1. Molecules and their Interaction Relevant to Biology

Which structure below is PRPP?
TLS Online TPP Program

#Question id: 29587

#Unit 6. System Physiology – Plant

Following are given stages of gibberellin biosynthetic pathway;
a) Geranylgeranyl diphosphate (GGPP) is converted to ent-kaurene  via copalyl diphosphate (CPP) in endoplasmic reticulum
b) In the endoplasmic reticulum, conversion of ent-kaurene into GA12 or GA53 depending on whether the GA is hydroxylated at carbon 13
c) the conversion of GA12 or GA53 into other GAs in cytosol proceeds with a series of oxidations at carbon 20
d) GA20 is then oxidized to the active gibberellin, GA1, by a 3β-hydroxylation reaction

Which of the following is the correct statements of GA biosynthesis?
TLS Online TPP Program

#Question id: 34101

#Unit 3. Fundamental Processes

DNA polymerases fall into five families based on sequence Homologies; all have conserve
A. Finger domain
B. Thumb domain
C. Palm domain
D. Proofreading domain
TLS Online TPP Program

#Question id: 2000

#Unit 4. Cell Communication and Cell Signaling

Which of the following is true of the successful development of a vaccine to be used against a pathogen?