Practice Questions

TLS Online TPP Program

#Question id: 7130

Hematopoietic stem cells can be isolated and grown in culture; if one wished to control their differentiation into either neutrophils or macrophages, what colony stimulating factors could be used?

#Unit 5. Developmental Biology

First, GM-CSF and IL-3 would be added to trigger formation of the granulocyte/macrophage lineage; then, the addition of either G-CSF or M-CSF would select between further differentiation as neutrophils or macrophages, respectively.
Since stem-cell factor (SCF) would maintain the cells as stem cells, the elimination of SCF would trigger differentiation into granulocyte/macrophage precursors; no further manipulation would be necessary.
The stem cells could be simultaneously stimulated with G-CSF, M-CSF, GM-CSF, and IL-3; half would become neutrophils and the other half would become macrophages; no further control is possible.
Since hematopoietic stem cells can become only erythrocytes, neutrophils, or macrophages, and no other cell types, the elimination of erythropoietin (EPO) would be sufficient to trigger formation of neutrophils and macrophages.

More Questions

#Question id: 12299

#Unit 10. Ecological Principles

#Question id: 3487

#Unit 11. Evolution and Behavior

Which of the following is true of innate behaviors?

A) Genes have very little influence on the expression of innate behaviors.

B) Innate behaviors tend to vary considerably among members of a population.

C) Innate behaviors are limited to invertebrate animals.

D) Innate behaviors are expressed in most individuals in a population across a wide range of environmental conditions.

E) Innate behaviors occur in invertebrates and some vertebrates but not in mammals.

#Question id: 1341

#Unit 4. Cell Communication and Cell Signaling

Which of the following molecules forms extracellular cross-linked fibrils of great tensile strength?

#Question id: 5103

#Unit 5. Developmental Biology

The arrangement of organs and tissues in their characteristic places in 3-D space defines ________.

#Question id: 29427

#Unit 6. System Physiology – Plant

Which of the following enzyme elicits a conformational change of rubisco that reduces its binding affinity for sugar phosphates in presence of light