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10.4 Immunofluorescence & Flow Cytometry — Test 1
Q1. Immunofluorescence microscopy localises antigens in cells/tissues using antibodies labelled with:✓ Fluorochromes (fluorescent dyes)
Q2. Direct immunofluorescence differs from indirect immunofluorescence in that direct uses:✓ A single fluorochrome-labelled primary antibody
Q3. Indirect immunofluorescence is more sensitive than direct because:✓ Several labelled secondary antibodies bind one primary, amplifying signal
Q4. Flow cytometry analyses cells by:✓ Passing labelled cells single-file through a laser and measuring scatter/fluorescence
Q5. In flow cytometry, forward scatter (FSC) primarily indicates a cell's:✓ Size
Q6. Side scatter (SSC) in flow cytometry reflects a cell's:✓ Internal complexity/granularity
Q7. A major clinical use of flow cytometry is:✓ Counting CD4⁺ T cells to monitor HIV/AIDS
Q8. Fluorescence-activated cell sorting (FACS) extends flow cytometry by:✓ Physically separating and collecting cells of interest
Q9. To analyse intracellular antigens (e.g. cytokines) by flow cytometry, cells must first be:✓ Fixed and permeabilised
Q10. Gating in flow cytometry refers to:✓ Selecting a defined cell population for analysis based on its parameters
Q11. Multicolour flow cytometry allows:✓ Simultaneous detection of several markers using different fluorochromes
Q12. Immunohistochemistry differs from immunofluorescence mainly in that it typically uses:✓ An enzyme label producing a coloured deposit viewed by light microscopy
Q13. A control showing no primary antibody (only the labelled secondary) is used in immunofluorescence to:✓ Detect non-specific binding/background of the secondary antibody
Q14. Confocal microscopy improves on standard fluorescence microscopy by:✓ Producing sharper optical sections by excluding out-of-focus light
Q15. Compensation in multicolour flow cytometry corrects for:✓ Spectral overlap (spillover) between fluorochromes
Q16. Antinuclear antibody (ANA) testing by indirect immunofluorescence detects:✓ Autoantibodies binding nuclear antigens, shown as nuclear staining patterns
Q17. A fluorochrome's role is to:✓ Emit detectable light when excited, marking where the antibody bound
Q18. Immunophenotyping by flow cytometry is valuable in haematology to:✓ Classify leukaemias/lymphomas by their surface marker (CD) profile
Q19. A key advantage of flow cytometry over microscopy for counting is that it:✓ Rapidly and objectively analyses large numbers of cells with multiple parameters
Q20. Match each term with its description and select the correct option.✓ A-iii, B-i, C-ii, D-iv