TLS Online TPP Program

#Question id: 14900


polymer-trapping model explains symplastic loading in plants, This model states that the sucrose diffussion takes place through cell to cell via plasmodesmata; which of the following prediction about the diffusion mechanism is INCORRECT?    

#Unit 6. System Physiology – Plant
  1. Sucrose, synthesized in the mesophyll, diffuses from the bundle sheath cells into the intermediary cells through the abundant plasmodesmata
  2. In the intermediary cells, raffinose is synthesized from sucrose and galactinol, Because of its smaller size, raffinose is able to diffuse back into the mesophyll
  3. Plasmodesmata between the intermediary cells and sieve elements must be wider and allow passage of raffinose and stachyose
  4. Raffinose is able to diffuse into the sieve elements. As a result, the concentration of transport sugar rises in the intermediary cells and the sieve elements.
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TLS Online TPP Program

#Question id: 8782

#Unit 9. Diversity of Life Forms

A phylogenetic tree is shown for the three domains of life (Eukarya, Archaea, and Bacteria). The tree branches in two directions from the first point, labeled Common ancestor of all life. One branch leads in the direction of Eukarya and Archaea, and the other branch leads to Bacteria. The branch leading to Eukarya and Archaea divide, one branch leading to each domain. The branch leading to Eukarya divides into four branches. One leads to Euglenozoans, and the other three lead to branching points. The first leads to Forams in one direction, and another branching point in the other that leads to Diatoms and Ciliates. The second branching point leads to Red algae in one direction, and a branching point that leads to green algae and land plants in the other direction. The third branching point leads to amoebas in one direction, and a branching point that leads to fungi and animals in the other direction. Land plants, Fungi and Animals are all highlighted.


Cyanobacteria were once called blue-green algae because they are photosynthetic. According to the phylogeny shown, the cyanobacteria are more closely related to gram-positive bacteria than to ________.

TLS Online TPP Program

#Question id: 8783

#Unit 9. Diversity of Life Forms

Which of the following statements is accurate, at least according to our present knowledge?

TLS Online TPP Program

#Question id: 8787

#Unit 9. Diversity of Life Forms

Which of the following statements is accurate, at least according to our present knowledge?

TLS Online TPP Program

#Question id: 8788

#Unit 9. Diversity of Life Forms

A phylogenetic tree is shown for the three domains of life (Eukarya, Archaea, and Bacteria). The tree branches in two directions from the first point, labeled Common ancestor of all life. One branch leads in the direction of Eukarya and Archaea, and the other branch leads to Bacteria. The branch leading to Eukarya and Archaea divide, one branch leading to each domain. The branch leading to Eukarya divides into four branches. One leads to Euglenozoans, and the other three lead to branching points. The first leads to Forams in one direction, and another branching point in the other that leads to Diatoms and Ciliates. The second branching point leads to Red algae in one direction, and a branching point that leads to green algae and land plants in the other direction. The third branching point leads to amoebas in one direction, and a branching point that leads to fungi and animals in the other direction. Land plants, Fungi and Animals are all highlighted.

Examine the figure. If you were a graduate student trying to develop a thesis project that would resolve polytomies, which of the following groups would you study?

TLS Online TPP Program

#Question id: 8789

#Unit 9. Diversity of Life Forms

If additional DNA sequence evidence shows that yeast genes for synthesizing proteins are more similar to protein-synthesizing genes in bacteria than those in archaea, a modern systematist would ________.

TLS Online TPP Program

#Question id: 8840

#Unit 9. Diversity of Life Forms

There are at least a dozen known species in the extinct genus Lystrosaurus. If each species was suited to a quite different environment, then this relatively large number of species is likely due to