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This activity was created by Kelly Riedell for students in Biology class at Brookings High School. 
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Students can practice mitosis/meiosis steps using yarn manipulatives


Cut out the yarn pieces according to directions and place in ziplock baggies.
Students can work individually or with a partner. Each will need a baggie with yarn pieces.

Walk students through the phases of mitosis and have them move the yarn pieces on their desks as each step is discussed.  After they have practiced all the phases, quiz them by naming different phases and have them create them on their desks. Activity can be repeated when learning about meiosis so students can see how it is different (synapsis, independent assortment, etc)

INTERPHASE: (IN between dividing)
Set up cell membrane on desk (Use black string to make a big oval on the desk).
DNA will switch back and forth between chromatin (long) and chromosomes (short) pieces during the activity.
In interphase DNA is spread out as chromatin. Cells start with 6 chromosomes.
    (Count out 3 long purple and 3 long green strings and place in center of cell)
Nuclear membrane is visible (Place pink yarn piece around the DNA)

Image by Riedell
During S phase DNA is copied. Hold up each chromatin yarn piece and place a "copy" along side of it.
(Use the 3 extra long purple/green strings) 
Replace DNA in nucleus

PROPHASE: (First dividing phase- Pros are #1)
Chromatin condenses into chromosomes (Replace longer yarn pieces in nucleus with shorter ones)
Remember to keep the chromatid "copies" together.
Nucleus/nucleolus disappears. (Remove pink yarn piece around chromosomes)
Images by Riedell
Centrioles/Spindle appear (students play role of spindle with their fingers)


Chromosomes line up in middle of cell. {Spindle (fingers) move chromosomes to middle of cell}

Image by Riedell


Chromatid arms separate and move to opposite ends of cell (Use fingers to separate chromatid arms)

Image by Riedell

Count chromosomes. You started with 6 (3 large, medium, small purple &  3 large, medium, small green)
How many does your cell have now?  (Should have 3 purple and 3 green; check to make sure you have one L, M, S purple and one L, M, S, green)

Images by Riedell
Chromosomes spread back out into chromatin (Replace short yarn pieces with longer yarn pieces)
Nucleus/nucleolus return (Put pink string around each set of chromosomes.)
Spindle/centrioles disappear.

CYTOKINESIS (Cytoplasm splits)
Animal cells use a cleavage furrow.
(Have students push cell membrane together in middle to make two cells)
Plant cells make a cell plate
(Have students use their orange string to make a wall instead of pinching)
Images by Riedell


Homologous partners match up (synapsis) and crossing over occurs

Image by Riedell

Homologous partners line up in middle together
Image by Riedell

Homologous partners separate/chromatids stay together
Independent assortment

Image by Riedell


Image by Riedell

Chromatids separate

Image by Riedell

Cells end up with only 3 chromosomes (one L, M, S)
Independent assortment gives different color combinations

Image by Riedell



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