Cheek cells

Summary

Look at cheek cells stained with methylene blue, or iodine, under the transmission microscope.

Science content

Biology: Features, Adaptations of Living Things (K, 1, 3, 7)

Biology: Sensing, Organ Systems (4, 5, 6)

Science competencies (+ questioning + manipulation + others that are in every activity)

Planning/conducting: planning investigations (3 up)

Processing/analyzing: classifying data, finding patterns (1 up)

Lessons activity is in

DNA extraction from cheek cells

Materials

flat (non-pointy) toothpick
glass slide and cover slip
methylene blue, 1% (0.5% in some fish medicines works great). If not available use tincture of iodine, from the drug store
microscope, ideally with a 40X lens

Procedure

Students add a drop of methylene blue (or iodine) to a slide.
Students scrape cheek cells from the inside of their cheeks using a toothpick, then spin the toothpick in the drop on the glass slide to shake them into the methylene blue.
Lay a cover slip over the drop with cells in it.
Look at the cheek cells under low power to start to find the cells.
Then increase the power, keeping a good-looking cell in the centre when moving up to the highest power.
Look for the nucleus in the centre of the cell.
With methylene blue, other cell organelles are also visible, and sometimes bacteria (dark blue spots outside the cheek cells).

Notes

Primary students, and many intermediates, need a strong teacher presence around the microscope.

Grades taught

Gr 1

Gr 2

Gr 3

Gr 4

Gr 5

Gr 6

Gr 7

Activity