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TLS Online TPP Program

#Question id: 1440

Which of the following is NOT evidence that smoking causes lung cancer?

#Unit 4. Cell Communication and Cell Signaling

  1. Epidemiological rates of lung cancer dramatically increased after more people started to smoke.

  2. Exposure of lung cells to the active carcinogen found in cigarettes causes mutations in p53.

  3. Mutations in p53 are found in the same codons in patients with lung cancer who smoke as in cultured cells treated with benzo(a)pyrene.

  4. Epidemiological rates of lung cancer in women increased years after the rates in men increased.

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TLS Online TPP Program

#Question id: 12178

#Unit 2. Cellular Organization

Following statements are regarding to V-class ATPases.
A. An organelle lumen or an extracellular space to become acidic, movement of protons must be accompanied by movement of an equal number of anions (e.g., Cl−) in the same direction.
B. An organelle lumen or an extracellular space to become acidic, movement of protons must be accompanied by movement of equal numbers of a different cation in the same direction.
C. An organelle lumen or an extracellular space to become acidic, movement of protons must be accompanied by movement of equal numbers of a different cation in the opposite direction.
D. An organelle lumen or an extracellular space to become acidic, movement of protons must be accompanied by movement of an equal number of anions (e.g., Cl−) in the opposite direction.
Which of the following combination is correct?
TLS Online TPP Program

#Question id: 12179

#Unit 2. Cellular Organization

Match the following human ABC proteins (Column I) with their function (Column II)

Which of the following is correct?
TLS Online TPP Program

#Question id: 12180

#Unit 2. Cellular Organization

Following statements are regarding to cotransport.
A. The two forces constituting the electrochemical gradient—the membrane electric potential and the ion concentration gradient—may act in the same or opposite directions.
B. Cotransporters use the energy released by movement of an ion (usually H+ or Na+) down its electrochemical gradient to power the import or export of a small molecule or different ion against its concentration gradient.
C. Cotransporters use the energy released by movement of an ion (usually H+ or Na+) down its electrochemical gradient to power the import or export of a small molecule or different ion down its concentration gradient.
D. The cells lining the small intestine and kidney tubules contain symporters that couple the energetically favorable entry of Na+ to the import of glucose against its concentration gradient.
Which of the following is incorrect?
TLS Online TPP Program

#Question id: 12181

#Unit 2. Cellular Organization

Following statements are regarding to the CFTR.
A. cystic fibrosis transmembrane conductance regulator allows Cl− ions to flow out of the cell, following their concentration gradient.
B. ATP binding to CFTR’s two nucleotide-binding domains appears to close the Cl− channel, and the hydrolysis of one ATP opens it (the other ATP remains intact).
C. the CFTR channel can open only if its regulatory domain (which is unique among ABC transporters) has been phosphorylated, thus regulating the flow of ions across the membrane.
D. The maintenance of electrical neutrality requires that the Cl− ions transported by the CFTR be accompanied by positively charged ions, mainly Na+. The transported ions are osmotically accompanied by water, thus maintaining the proper level of fluidity in secretions of the airways, intestinal tract, and the ducts of the pancreas, testes, and sweat glands.
Which of the following combination is correct?
TLS Online TPP Program

#Question id: 24651

#Unit 2. Cellular Organization

For the SERCA pump, how many Ca2+ ions moves across the membrane during each catalytic cycle ?
TLS Online TPP Program

#Question id: 24652

#Unit 2. Cellular Organization

The mechanism postulated for P-type ATPases takes into account the large conformational changes and the phosphorylation dephosphorylation of the critical: