Practice Questions

  1. Home
  2. Free Resources
  3. Practice Questions
  4. 5912
TLS Online TPP Program

#Question id: 7112

Although the vertebrate body plan outwardly displays a mirror-image symmetry with regard to left and right, the internal organs are not symmetrical. How does this left-right asymmetry develop?

#Unit 5. Developmental Biology
  1. The two cells of the Nieuwkoop center (at the 32-cell stage) signal each other and become either left or right.
  2. Maternal factors that determine left and right are packaged into the egg, just as dorsalizing factors are.
  3. Differential release of Ca2+ ions on the left side leads to expression of Nodal and Pitx2 on the left.
  4. Gravity determines the left-right axis: that side which is down becomes right and that side which is up becomes left.
More Questions
TLS Online TPP Program

#Question id: 5216

#Unit 11. Evolution and Behavior

Alu elements account for about 10% of the human genome. What does this mean?
TLS Online TPP Program

#Question id: 5217

#Unit 11. Evolution and Behavior

Multigene families include two or more nearly identical genes or genes sharing nearly identical sequences. A classical example is the set of genes for globin molecules, including genes on human chromosomes 11 and 16. How might identical and obviously duplicated gene sequences have gotten from one chromosome to another?
TLS Online TPP Program

#Question id: 5218

#Unit 11. Evolution and Behavior

Several of the different globin genes are expressed in humans, but at different times in development. What mechanism could allow for this?
TLS Online TPP Program

#Question id: 5219

#Unit 11. Evolution and Behavior

What is it that can be duplicated in a genome?
TLS Online TPP Program

#Question id: 5220

#Unit 11. Evolution and Behavior

In comparing the genomes of humans and those of other higher primates, it is seen that humans have a large metacentric pair we call chromosome #2 among our 46 chromosomes, while the other primates of this group have 48 chromosomes and any pair like the human #2 pair is not present; instead the primate groups each have two pairs of midsize acrocentric chromosomes. What is the most likely explanation?
TLS Online TPP Program

#Question id: 5221

#Unit 11. Evolution and Behavior

Unequal crossing over during Prophase I can result in one sister chromosome with a deletion and another with a duplication. A mutated form of hemoglobin, known as hemoglobin Lepore, is known in the human population. Hemoglobin Lepore has a deleted set of amino acids. If it was caused by unequal crossing over, what would be an expected consequence?