The Turing model provides a framework for limb development. Following statements are regarding to this model:

A. In Turing’s model, morphogen A promotes the production of more morphogen A (autoactivation) as well as production of morphogen I. Morphogen I, however, inhibits the production of morphogen A (lateral inhibition).

B. In Turing’s model, morphogen A inhibits the production of more morphogen A (autoinhibition) as well as production of morphogen I. Morphogen I, however, promotes the production of morphogen A (lateral activation).

C. In Turing’s model, the reaction-diffusion dynamics can tell us how the limb bud acquires its proximal- distal polarity as well as how the number of digits is regulated at the distal tip of the limb.

D. The reaction-diffusion system has been proposed to be sufficient for establishing patterns of precartilage and noncartilage tissues.

E. According to this model, along the proximal-distal axis the AER dividing into two domains 1-the inhibitory domain 2-the active domain.

F. According to this model, along the proximal-distal axis the AER dividing into three domains 1-the inhibitory domain 2-the active domain 3-frozen domain.

Which of the following combinations are incorrect?

#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?

#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.

#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.

#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.

#Question id: 2916

#Unit 2. Cellular Organization

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

#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?