You Have Used Fluorescence-Activated Cell Sorting to Separate Blood T

question 47

Short Answer

You have used fluorescence-activated cell sorting to separate blood T lymphocytes from a healthy person and a patient infected with a virus. To sort the cells, you used antibodies against two cell-surface receptors, CD4 and CD8, each conjugated to a different fluorescent dye. Based on the results below, which cell type do you think is depleted by the viral infection: CD4+ helper T cells (H) or CD8+ cytotoxic T cells (C)? In these dot plots, each cell is represented by a dot whose coordinates are the intensities of CD4 and CD8 signals. Write down H or C as your answer.

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Definitions:

Trophic Levels

Refers to the hierarchical levels in an ecosystem, categorized by how energy is obtained, ranging from producers to primary consumers and up to apex predators.

Carnivore

An animal that mainly feeds on other animals; a mammal belonging to order Carnivora (e.g., wolves or seals).

Photosynthetic Organisms

Organisms capable of photosynthesis, a process that converts light energy into chemical energy, sustaining the food chain.

Autotroph

An organism that synthesizes complex organic compounds from simple inorganic raw materials; also called producer or primary producer. Compare with heterotroph. See chemoautotroph and photoautotroph.