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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: 12072

#Unit 7. System Physiology – Animal

If the average hydrostatic pressure in the glomerular capillaries is 50 mm Hg, the hydrostatic pressure in the Bowman’s space is 12 mm Hg, the average colloid osmotic pressure in the glomerular capillaries is 30 mm Hg, and there is no protein in the glomerular ultrafiltrate, what is the net pressure driving glomerular filtration?
TLS Online TPP Program

#Question id: 12074

#Unit 7. System Physiology – Animal

Which of the following tends to increase potassium secretion by the cortical collecting tubule?
TLS Online TPP Program

#Question id: 12076

#Unit 7. System Physiology – Animal

Furosemide (Lasix) is a diuretic that also produces natriuresis. Which of the following is an undesirable side effect of furosemide due to its site of action on the renal tubule?
TLS Online TPP Program

#Question id: 12219

#Unit 7. System Physiology – Animal

When the dietary intake of K+ increases, body K+ balance is maintained by an increase in K+ excretion primarily by which of the following?
TLS Online TPP Program

#Question id: 12221

#Unit 7. System Physiology – Animal

Juvenile (type I) diabetes mellitus is often diagnosed because of polyuria (high urine flow) and polydipsia (frequent drinking) that occur because of which of the following?
TLS Online TPP Program

#Question id: 12222

#Unit 7. System Physiology – Animal

In acidosis, most of the hydrogen ions secreted by the proximal tubule are associated with which of the following processes?