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TLS Online TPP Program

#Question id: 1260

Which of the following statement regarding RTK/Ras pathway is incorrect?

#Unit 4. Cell Communication and Cell Signaling

  1. Receptor activation leads to re-localization of Sos from the cytosol to the membrane, which brings Sos close to its substrate, Ras∙GDP, which is already bound to the plasma membrane by means of a covalently attached lipid.

  2. Binding of Sos to Ras∙GDP leads to conformational changes in the switch I and switch II segments of Ras, thereby opening the binding pocket for GDP so it can diffuse out.

  3. The SH2 domains in GRB2 selectively bind to proline-rich sequences in Sos; different SH3 domains in other proteins bind to proline-rich sequences distinct from those in Sos.

  4. Ras is activated by the exchange of GDP for GTP. Active Ras∙GTP binds to the N-terminal regulatory domain of Raf, a serine/threonine kinase, thereby activating its kinase activity.

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TLS Online TPP Program

#Question id: 16777

#Unit 13. Methods in Biology

What is the formula for the median of Grouped data? 
TLS Online TPP Program

#Question id: 391

#Unit 1. Molecules and their Interaction Relevant to Biology

In a hospital laboratory, a 10.0 mL sample of gastric juice, obtained several hours after a meal, was titrated with 0.1 M NaOH to neutrality; 7.2 mL of NaOH was required. The patient’s stomach contained no ingested food or drink, thus assume that no buffers were present. What was the pH of the gastric juice?
TLS Online TPP Program

#Question id: 1407

#Unit 4. Cell Communication and Cell Signaling

Which of the following is pro-apoptotic?

a. Bax              b. Bcl-2                       c. p53              d. protein kinase B      e. PTEN
TLS Online TPP Program

#Question id: 24576

#Unit 10. Ecological Principles

The birth of 100 cockroaches to a population of 1,000 would represent a birth rate. Similarly, the death of 50 cockroaches in a population of 1,000 would be a death rate, d, per individual per week. Calculate the rate of change in a population per unit time ?
TLS Online TPP Program

#Question id: 2624

#Unit 2. Cellular Organization

What is negative regulation of lac operon