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TLS Online TPP Program

#Question id: 12835

Following statements are regarding to the surveillance mechanism. Which of the following statement is incorrect?

#Unit 2. Cellular Organization
  1. DNA damage leads to the activation of p21, a transcription factor that induces the expression of the gene encoding the CDK inhibitor p53.
  2. When the DNA damage occurs during S phase or in G2, Cdc25C inhibition by Chk1/2 results in the inhibition of mitotic CDKs and hence arrest in G2.
  3. Cells sense DNA replication stress that results in stalling or slowing of replication forks. Such stress triggers activation of the ATR-Chk1 checkpoint pathway and results in downregulation of S phase CDK activity and prevents the firing of late-replicating origins.
  4. ATM halts cell cycle progression by Chk2-mediated inhibition of Cdc25, thus preventing activation of CDKs. This inhibition can occur in G1 or G2.
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TLS Online TPP Program

#Question id: 12097

#Unit 10. Ecological Principles

The herbaceous plant Achillea lanulosa is widespread in the Northern Hemisphere. Phenotypic variation in the species has been extensively studied along an altitudinal gradient from sea level to over 3,000 meters. In California there is conspicuous variation in  height; alpine plants are only several centimeters tall  while  those in  the San Joaquin Valley may reach a height of 1.8 meters. Adaptation to different local environments also results in variation in physiological processes such as photosynthetic rate, resistance to cold, and the timing of dormancy.


Which of the following methods would be best to determine whether the phenotypic variation in Achillea lanulosa is due to genotypic variation?
TLS Online TPP Program

#Question id: 12096

#Unit 10. Ecological Principles

An important evolutionary benefit of sexual reproduction is that
TLS Online TPP Program

#Question id: 12095

#Unit 10. Ecological Principles

It is now thought that the atmosphere of the primitive Earth was composed largely of carbon dioxide, nitrogen, and water vapor. The composition of certain iron-containing minerals suggests that the carbon dioxide began to be replaced by oxygen about 2 billion years ago.   Which of the following is the best explanation for the change in atmospheric composition?
TLS Online TPP Program

#Question id: 12094

#Unit 10. Ecological Principles

Which of the following plant groups is now extinct?
TLS Online TPP Program

#Question id: 12093

#Unit 10. Ecological Principles

The resemblance of body structure and mode of life of some species of Australian marsupials to certain species of placental mammals is an example of
TLS Online TPP Program

#Question id: 12092

#Unit 10. Ecological Principles

The phenomenon of genetic drift is most likely to occur in populations that