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TLS Online TPP Program

#Question id: 13207

The polymer-trapping model explains symplastic loading in plants with intermediary-type companion cells, this model makes three prediction; which one of the following prediction is INCORRECT?

#Unit 6. System Physiology – Plant
  1. Sucrose should be more concentrated in the mesophyll than in the intermediary cells
  2. The enzymes for raffinose and stachyose synthesis should be preferentially located in the intermediary cells
  3. The plasmodesmata linking the bundle sheath cells and the intermediary cells should exclude molecules larger than sucrose
  4. Plasmodesmata between the intermediary cells and sieve elements must be smaller donot allow passage of raffinose and stachyose
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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: 1547

#Unit 4. Cell Communication and Cell Signaling

follicular dendritic cells (FDCs) secrete CXCL13 and its receptor, CXCR5, which is expressed on B cells, function of this interaction ?
TLS Online TPP Program

#Question id: 12349

#Unit 10. Ecological Principles

Males in a population differ in the time they spend displaying to females. A researcher hypothesizes that predators are responsible for these differences. Males display for longer durations when there are no predators in the vicinity and for shorter durations when there is a predator nearby. Which of the following study designs is the most appropriate test of this hypothesis?
TLS Online TPP Program

#Question id: 9204

#Unit 9. Diversity of Life Forms

Which of the following observations provides the best evidence of a biodiversity crisis?
TLS Online TPP Program

#Question id: 5818

#Unit 8. Inheritance Biology

How does recombinational repair differ from nucleotide excision repair (NER)?