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TLS Online TPP Program

#Question id: 7246

Treatment of Xenopus embryos with lithium dorsalizes the embryos by interfering with cell-cell signaling pathways. What, if anything, is the effect of lithium on hydra, and what might we infer about its mechanism of action?

#Unit 5. Developmental Biology
  1. Lithium has no effect in hydra
  2. Lithium dorsalizes hydra just as it does Xenopus, so we would assume its mechanism of action is identical in the two organisms
  3. Lithium causes the formation of extra basal discs, which we might infer arise through interference with cell-cell signaling pathways
  4. Lithium causes the formation of extra head regions, since the head of hydra is mechanistically analogous to the dorsal side of Xenopus embryos
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TLS Online TPP Program

#Question id: 19054

#Unit 13. Methods in Biology

Which is not an application of TLC?
TLS Online TPP Program

#Question id: 26807

#Unit 8. Inheritance Biology

In case of mammals, which of the following signalling molecules are responsible for making decision for entry into meiosis?
TLS Online TPP Program

#Question id: 26959

#Unit 10. Ecological Principles

In the quadrat methods, given R= (mean distance) X 2 √density, Define the correct pattern of spacing with respect to R?

a.R is equal to 1, then the population is randomly dispersed

b.R is greater than 1, then the population is evenly dispersed

c.R is less than 1, then the population is clumped

d.R is equal to 1, then the population is evenly dispersed

e.R is greater than 1, then the population is randomly dispersed
TLS Online TPP Program

#Question id: 5542

#Unit 5. Developmental Biology

One stage of cleavage is the morula stage which is:
TLS Online TPP Program

#Question id: 3928

#Unit 3. Fundamental Processes

An extremely large lactose source is encountered by an E. coli cell in the lumen of the small intestine of a human who just ate an entire carton of ice cream. Which of the following would most likely be a contributor to why the E. coli does not metabolize any of the lactose?