Stage thymocytes express neither CD4 nor CD8, markers associated with mature T cells. They are therefore called double negative (DN) cells. DN cells first travel to the region under the thymic capsule, a region referred to as the ________, where they proliferate and begin to generate their T-cell receptors. Thymocytes that successfully express TCRs begin to express both CD4 and CD8, becoming double positive (DP) cells, and populate the cortex, the site where most (85% or more) immature T cells are found.

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#Question id: 714

#Unit 1. Molecules and their Interaction Relevant to Biology

What is  the length of a polypeptide with 100 amino acids residue in a single contiguous alpha helix?

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#Question id: 12041

#Unit 7. System Physiology – Animal

Which of the following is not normally found in abundance in the portal blood?

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#Question id: 11453

#Unit 7. System Physiology – Animal

Which type of receptor would you expect to be most abundant in the antennae of a moth?

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#Question id: 12573

#Unit 10. Ecological Principles

Which of the following conditions is the most likely indicator of a population in an extinction vortex? 

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#Question id: 4147

#Unit 3. Fundamental Processes

Which one of the following antibiotics does not function by interfering with the translational process?