TLS Online TPP Program

#Question id: 7117


Which of the following statements explains why gain-of-function mutation of Pmar1 results in a vegetalized embryo:

#Unit 5. Developmental Biology
  1. Beta catenin has the highest concentration in the micromeres
  2. Pmar1 is activated by maternal beta-catenin and Otx
  3. HesC transcription is repressed; skeletogenic genes are activated in all cells

  4. HesC is activated; Delta protein induces mesodermal specification
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TLS Online TPP Program

#Question id: 12339

#Unit 10. Ecological Principles

If a species is a keystone predator, then its removal from a community should

TLS Online TPP Program

#Question id: 12778

#Unit 10. Ecological Principles

A population of white-footed mice becomes severely overpopulated in a habitat that has been disturbed by human activity. Sometimes intrinsic factors cause the population to increase in mortality and lower reproduction rates in reaction to the stress of overpopulation. Which of the following is an example of intrinsic population control?

TLS Online TPP Program

#Question id: 3970

#Unit 3. Fundamental Processes

In bacteria, an operon:

TLS Online TPP Program

#Question id: 2899

#Unit 2. Cellular Organization

The H3.H4 tetramers and H2A.H2B dimers each interact with a particular region of the DNA within the nucleosome.

I. Histone H3.H4 tetramers occupy a key position in the nucleosome by binding the middle and both ends of the DNA.

II. The amino-terminal region of H3 most proximal to the histone-fold region forms a fourth a-helix that interacts with the final 13 bp at each end of the bound DNA.

III. The relatively short length of DNA bound by H2A.H2B dimers is sufficient to prepare the DNA for H3.H4 tetramer binding.

IV. The H3.H4 tetramer forms the bottom part of the histone octamer located across the disc from the DNA ends whereas two H2A.H2B dimer occupies the top part.

Which of the following represents the correct binding of the histones with the DNA?

TLS Online TPP Program

#Question id: 18225

#Unit 7. System Physiology – Animal

________ refers to the long-term wear and tear on the body caused by the many simultaneous changes that need to occur to maintain homeostasis.