TLS Online TPP Program

#Question id: 2978


The most important regulatory control that restricts cyclins to the appropriate cell cycle stage is ubiquitin mediated, proteasome-dependent protein degradation. Which of the following statement is incorrect regarding to the degradation of protein?

#Unit 2. Cellular Organization
  1. SCF and APC/C are multisubunit ubiquitin-protein ligases that belong to the RING finger family of ubiquitin protein ligases which ensure that the cell cycle engine is driven forward and that cells cannot “go backward” in the cell cycle.

  2. SCF recognizes its substrates only when they are phosphorylated.

  3. The substrate specificity of active, dephosphorylated APC/C is determined in part by its association with one of two related substrate targeting factors called Cdc20 and Cdh1.

  4. The substrates of APC/C contain recognition motifs known as destruction box which is lysine rich.

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TLS Online TPP Program

#Question id: 402

#Unit 1. Molecules and their Interaction Relevant to Biology

If the DG'° of the reaction A -> B is –40 kJ/mol, under standard conditions the reaction:

TLS Online TPP Program

#Question id: 403

#Unit 1. Molecules and their Interaction Relevant to Biology

For the reaction A -> B, DG'° = –60 kJ/mol.  The reaction is started with 10 mmol of A; no B is initially present.  After 24 hours, analysis reveals the presence of 2 mmol of B, 8 mmol of A. Which is the most likely explanation?

TLS Online TPP Program

#Question id: 404

#Unit 1. Molecules and their Interaction Relevant to Biology

When a mixture of 3-phosphoglycerate and 2-phosphoglycerate is incubated at 25 °C with phosphoglycerate mutase until equilibrium is reached, the final mixture contains six times as much 2-phosphoglycerate as 3-phosphoglycerate.  Which one of the following statements is most nearly correct, when applied to the reaction as written?  (R = 8.315 J/mol·K; T = 298 K)  3-Phosphoglycerate -> 2-phosphoglycerate

TLS Online TPP Program

#Question id: 405

#Unit 1. Molecules and their Interaction Relevant to Biology

When a mixture of glucose 6-phosphate and fructose 6-phosphate is incubated with the enzyme phosphohexose isomerase (which catalyzes the interconversion of these two compounds) until equilibrium is reached, the final mixture contains twice as much glucose 6-phosphate as fructose 6-phosphate.  Which one of the following statements is best applied to this reaction outlined below? (R = 8.315 J/mol·K; T = 298 K) Glucose 6-phosphate -> fructose 6-phosphate

TLS Online TPP Program

#Question id: 406

#Unit 1. Molecules and their Interaction Relevant to Biology

Hydrolysis of 1 M glucose 6-phosphate catalyzed by glucose 6-phosphatase is 99% complete at equilibrium (i.e., only 1% of the substrate remains). Which of the following statements is most nearly correct? (R = 8.315 J/mol·K; T = 298 K)

TLS Online TPP Program

#Question id: 407

#Unit 1. Molecules and their Interaction Relevant to Biology

The reaction A + B -> C has a DG'° of –20 kJ/mol at 25° C.  Starting under standard conditions, one can predict that: