TLS Online TPP Program

#Question id: 7154


Cancer is believed to often arise from stem cells, rather than fully differentiated cells. Which of the following are consistent with this view?

#Unit 5. Developmental Biology
  1. Stem cells are actively dividing and express few differentiated functions, so they may have fewer changes to undergo than do fully differentiated cells in becoming cancer cells.
  2. DNA replication is necessary for mutations to occur, and stem cells are replicating their DNA whereas differentiated cells are for the most part not replicating their DNA.
  3. Teratocarcinomas are tumors that arise from germ cells or embryonic stem (ES) cells, under certain circumstances, demonstrating that tumors can arise from stem cells without further mutation.
  4. All of the above are reasons that cancer cells may more readily arise from stem cells than from fully differentiated cells.
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TLS Online TPP Program

#Question id: 8698

#Unit 9. Diversity of Life Forms

Use the figure to answer the following question.

If the figure above is an accurate depiction of relatedness, then which of the following should be an accurate statement?

TLS Online TPP Program

#Question id: 8699

#Unit 9. Diversity of Life Forms

Use the figure to answer the following question.

If the figure is an accurate depiction of relatedness, then which of the following should be an accurate statement?

TLS Online TPP Program

#Question id: 8700

#Unit 9. Diversity of Life Forms

Use the following figure and description to answer the question.

Humans, chimpanzees, gorillas, and orangutans are members of a clade called the great apes, which shared a common ancestor about 15 million years ago. Gibbons and siamangs comprise a clade called the lesser apes. Tree-branch lengths indicate elapsed time. Assuming chimps and gorillas are humans' closest relatives, removing humans from the great ape clade and placing them in a different clade has the effect of making the phylogenetic tree of the great apes ________.

TLS Online TPP Program

#Question id: 8701

#Unit 9. Diversity of Life Forms

The question refers to the following table, which compares the percent sequence homology of four different parts (two introns and two exons) of a gene that is found in five different eukaryotic species. Each part is numbered to indicate its distance from the promoter (for example, Intron I is the one closest to the promoter). The data reported for species A were obtained by comparing DNA from one member of species A to another member of species A.


Based on the tabular data, and assuming that time advances vertically, which phylogenetic tree is the most likely depiction of the evolutionary relationships among these five species?

TLS Online TPP Program

#Question id: 8702

#Unit 9. Diversity of Life Forms

The question refers to the following table, which compares the percent sequence homology of four different parts (two introns and two exons) of a gene that is found in five different eukaryotic species. Each part is numbered to indicate its distance from the promoter (for example, Intron I is the one closest to the promoter). The data reported for species A were obtained by comparing DNA from one member of species A to another member of species A.

Regarding these sequence homology data, the principle of maximum parsimony would be applicable in ________.

TLS Online TPP Program

#Question id: 8703

#Unit 9. Diversity of Life Forms

In a comparison of birds and mammals, having four limbs is ________.