Practice Questions

TLS Online TPP Program

#Question id: 7231

Kragl and colleagues (2009) performed an experiment in which they transplanted limb tissue from a salamander whose cells expressed green fluorescent protein (GFP) into different regions of limbs of normal salamanders that did not have the GFP transgene. If they transplanted the GFP-expressing limb cartilage into a salamander limb that did not contain the GFP transgene, the GFP-expressing cartilage would integrate normally into the limb skeleton. They later amputated the limb through the region containing GFP-marked cartilage cells. The blastema was found to contain GFP-expressing cells, and when the blastema differentiated, the only GFP-expressing cells found were in the limb cartilage. Similarly, GFP-marked muscle cells gave rise only to muscle, and GFP-marked epidermal cells only produced the epidermis of the regenerated limb. Which of the following phenomenon is proved according to experiment?

#Unit 5. Developmental Biology

These results suggest that nAG alone is the primary mitogen responsible for nerve-dependent regeneration.
The blastema is not a collection of unspecified multipotent progenitor cells. Rather, the cells retain their specification, and the blastema is a heterogeneous assortment of restricted progenitor cells.
The blastema is a collection of unspecified multipotent progenitor cells. Rather, the cells lost their specification, and the blastema is a homogeneous assortment of restricted progenitor cells.
Salamanders accomplish epimorphic regeneration by cell dedifferentiation to form a regeneration blastema, which in this case is an aggregation of relatively undifferentiated cells derived from the originally differentiated tissue that then proliferates and redifferentiates into the new limb parts.

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TLS Online TPP Program

#Question id: 12345

#Unit 10. Ecological Principles

Shannon's index of diversity is calculated using the equation below, where pi is the proportion of the ithShannon's index of diversity is calculated using the equation below, where pi is the proportion of the ith species and ln is natural logarithm. For a community with a given number of species, which of the following statements is true? species and ln is natural logarithm. For a community with a given number of species, which of the following statements is true?

TLS Online TPP Program

#Question id: 12346

#Unit 10. Ecological Principles

The schematic below shows the relationship between survivorship with age (relative to maximum lifespan) in Species 1 (dashed line) and Species 2 (solid line). Which of the following inferences is compatible with this figure?

TLS Online TPP Program

#Question id: 12347

#Unit 10. Ecological Principles

A team of conservation biologists, surveying a population of frogs on an island, captured and marked 312 individuals in the first sample. In a second sampling, 3 days later, the team caught 140 individuals of which 26 were previously marked. The total number of frogs on the island is estimated to be . (Use decimal notation, not fractions or percentage)

TLS Online TPP Program

#Question id: 12348

#Unit 10. Ecological Principles

The following equation represents a hypothetical relationship between fitness (w) and shoot: root ratio (r) in individuals of a plant species: w = 10r-10r2. At what value of shoot: root ratio (r), do these plants achieve maximum fitness? (Use decimal notation, not fractions or percentage)

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?