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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
  1. 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.
  2. 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.
  3. 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.
  4. 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.
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TLS Online TPP Program

#Question id: 2912

#Unit 2. Cellular Organization

HOTAIR is a lncRNA whose gene is found in the Hox C cluster in humans, but it acts by regulating expression of the Hox D genes on another chromosome (in trans) by recruiting to that locus Polycomb Repressive Complex 2. Which of the following statements is/are correct regarding this regulation?
TLS Online TPP Program

#Question id: 2913

#Unit 2. Cellular Organization

Genome size (the length of DNA associated with one haploid complement of chromosomes) varies substantially between different organisms. Because more genes are required to direct the formation of more complex organisms, it is not surprising that genome size is roughly correlated with an organism’s apparent complexity. Which of the following statements is/are correct in reference to this rough correlation?

I. Many organisms of apparently similar complexities have very different genome sizes.

II. The number of genes, rather than genome size, is more closely related to organism complexity.

III. There is a roughly inverse correlation between organism complexity and gene density—the less complex the organism, the higher the gene density.

IV. Gene density in eukaryotic organisms is consistently higher and more variable than in their prokaryotic counterparts.
TLS Online TPP Program

#Question id: 2914

#Unit 2. Cellular Organization

The human genome is composed of many different types of DNA sequences, the majority of which do not encode proteins. Shown are the distribution and amount of each of the various types of sequences. Mark the correct options containing appropriate input for boxes A and B.
TLS Online TPP Program

#Question id: 2915

#Unit 2. Cellular Organization

The structural maintenance of chromosome (SMC) proteins are extended proteins that form defined pairs by interacting through lengthy coiled-coil domains. Together with non-SMC proteins, they form multiprotein complexes that act to link two DNA helices together. Identify the SMC proteins in the figure given below and match them with their respective subunits.

i. Blue – Cohesin made up of Smc 1 and Smc 2 proteins.

ii. Green – Condensin made up of Smc 3 and Smc 4 proteins.

iii. Blue – Condensin made up of Smc 2 and Smc 4 proteins.

iv. Green – Cohesins made up of Smc 1 and Smc 3 proteins.

v. Blue – Condensin made up of Smc 1 and Smc 3 proteins.

vi. Green – Cohesins made up of Smc 2 and Smc 4 proteins.
TLS Online TPP Program

#Question id: 2916

#Unit 2. Cellular Organization

Which of the following statement is INCORRECT regarding the packaging of DNA into higher order chromatin structure?
TLS Online TPP Program

#Question id: 2917

#Unit 2. Cellular Organization

With respect to the interconversion between open and condensed chromatin shown below: Which of the directions (i) or (ii) would you anticipate would be the consequence of the following types of chromatin modification?