back to Third Quarter Assignments 09

Mitosis Paper Model Activity:
My Toe-Socks Dance- Mitosis (Class Activity)
In this activity it is helpful to again use to compare socks to chromosomes as an analogy. This is because sock come in pairs and they could be knitted from one long piece of thread. Mitosis is the movement of chromosomes from one nucleus into two nuclei. The performance dance steps will also move ones socks, so it might be helpful to think of mitosis as a dance done by the chromosomes. The sock analogies in this activity will be followed by what they model.

1. Cut out three pairs of chromosomes. Two these paper models will be five boxes long, two will be three boxes long and two will be two boxes long. You will have six strips of paper with five, three, or two boxes printed on them.
Human chromosomes can be compared to 23 pairs of socks.
Humans have 23 pairs of chromosomes, however for simplicity, only three pair will be used in this activity.
Socks can be distinguished from one another by length.
Length is one characteristic used to distinguish one chromosome from another.


2. Label each chromosome of a chromosome pairs by writing a 1 or a 2 after the word parent printed on them.
It is helpful to picture left socks come from one parent and right socks come form the other.
An organism gets their chromosomes form its parents. Half of each chromosome pair comes from a different parent. Chromosome pairs are called homologous chromosomes.

3. Label the genes one each model chromosome starting with numbers 1 from the top to bottom.
Genes on a chromosome can be compared to stripes on socks.
Note that the model chromosomes are divided into sections representing genes.
A gene is a section of DNA that contains the instructions for making a protein.

4. Label the genes with traits and also the expressions of the traits.
Chromosomes are like long pieces of yarn.
Chromosomes are actually composed of 300 to 3000 genes depending on its length.
Genes code for the development of traits.
Label the first gene on the short model chromosomes as eye color, then write the expression of this trait as brown on one and hazel on the other..
Label the second gene on the middle length chromosomes as blood type, then write the expression of this trait as A on one and B on the other.
Label the third gene on the long model chromosomes as ear lobe, then write the expression of this trait as free on one and attached on the other.

5. Randomly place the six chromosomes on your desktop. Your desk top will be used to represent the cell.
Imaging chromosomes in the nucleus like sock just thrown in a sock-drawer. The pair are not together or folded.

6. Interphase: (Label and cut out a copy of each model chromosome.)
If chromosomes were each one long piece of sock-yarn, during inter, it would turn in to two identical pieces.
Replications occurs during interphase, where each chromosome becomes two identical copies.
7. Kinetochore and centromeres (Place the copies side by side and connect them.)
If the chromosomes were long pieces of yarn they would knit themselves into socks at the end of Interphase.
The new identical copies of each sock would be connected (but left and right socks are not) representing sister chromatids.
Kinetochores connect the two sister chromatids at a narrowing called the centromere.

8. Prophase: (Start moving the sister chromatids towards the center of the desk.)
In the sock analogy, sister chromatids would be represented by two connected identical right (or two identical left socks).
Sister chromatids become visible during prophase due to the winding and condensing of each chromosome and its copy into sister chromatids. The nuclear membrane dissolves at this time.


9.Metaphase: (Move the sister chromatids and line them up.)
Sister chromatids line up randomly along the middle of the cell, but homologous pairs (left and right socks) don't come together.


10. Anaphase: (Separate the sister chromatids and slide them in opposite directions away from the middle of the cell)
In anaphase, the two identical sets of chromosomes move apart. In the sock analogy, identical socks move apart.


11. Telophase: (Group each set of chromosomes in the daughter cells so a nuclear membrane could from around them)
Cytokinesis occurs during telophase, which is the division of the cytoplasm.
Nuclear membranes also form around the chromosomes of the daughter cells during telophase.