Using an Optical Microscope (AQA A-Level Biology): Flashcards

Magnifies biological structures too small to see with naked eye

$\times$4 (low), $\times$10 (medium), $\times$40 (high power)

Rotating mechanism that holds objective lenses and switches magnification

Focuses light onto specimen using iris diaphragm

Precise focusing, particularly with high-power objectives

Must be transparent or very thin to allow light through

Prevent osmotic damage (same water potential as cytoplasm)

Make transparent cellular structures visible

Colours DNA, makes chromosomes visible during cell division

Must be calibrated with stage micrometer (has no fixed units)