Virtual Labs

Isolation and Microscopic Visualization of T cells and B cells

1. What is the first step in the isolation of lymphocytes from peripheral blood?

a: Layer the blood sample onto a density gradient medium Explanation

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b: Dilute collected blood with equal volume of PBS buffer Explanation

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c: Add an anticoagulant to the blood sample Explanation

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d: Centrifuge the blood sample at high speeds Explanation

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2. What is the function of washing the isolated lymphocytes before staining with Leishman stain?

a: To remove residual Ficoll Hypaque solution and Platelets Explanation

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b: To lyse the red blood cells Explanation

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c: To prevent the lymphocytes from adhering to the slide Explanation

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d: To enhance the staining of the lymphocytes Explanation

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3. What is the principle of Leishman staining?

a: It stains the cytoplasm of the cells Explanation

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b: It stains the nuclei of the cells Explanation

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c: It stains the cell membranes of the cells Explanation

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d: It stains the mitochondria of the cells Explanation

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4. Which cell culture media is used to culture lymphocytes?

a: DMEM Explanation

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b: MacConkey Agar Explanation

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c: LB broth Explanation

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d: RPMI 1640 Explanation

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5. How do lymphocytes appear upon Leishman staining?

a: Pale pink cytoplasm with dark blue nuclei and orange-red granules Explanation

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b: Pink-Red Explanation

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c: Blue cytoplasm with dark purple nuclei Explanation

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d: Purple cytoplasm with dark blue nuclei Explanation

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6. What is the purpose of using EDTA when collecting whole blood for lymphocyte isolation?

a: To lyse the red blood cells Explanation

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b: To promote coagulation Explanation

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c: To avoid coagulation Explanation

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d: To fix cells Explanation

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7. What is the 'Buffy coat' layer primarily composed of after centrifugation?

a: Red blood cells Explanation

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b: Platelets Explanation

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c: Plasma Explanation

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d: Mononuclear cells Explanation

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8. What is the role of memory B or T cells?

a: To initiate an immediate immune response upon re-exposure to the same antigen Explanation

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b: To present antigens to naive B and T cells Explanation

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c: To secrete antibodies continuously Explanation

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d: To regulate cytokine production Explanation

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9. Which of the following is true about B-cell receptors (BCR)?

a: They have a single antigen-binding region. Explanation

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b: They are composed of Igα/Igβ heterodimers and membrane immunoglobulin. Explanation

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c: They recognize antigens processed by MHC. Explanation

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d: They do not undergo clonal expansion. Explanation

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10. Why is it important to avoid mixing the diluted blood with Ficoll-Hypaque during the layering step?

a: To prevent contamination Explanation

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b: To maintain the density gradient for effective cell separation Explanation

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c: To enhance cell proliferation Explanation

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d: To promote staining Explanation

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