Class Summary - We started out today with a short quiz on the cell cycle from last class period. Today we will revisit and talk about DNA replication. We reviewed DNA replication and simplified it. Today we will do an activity to simulate DNA Replication. We will label scissors with a ‘helicase’ label to unwind and cut a paper double helix DNA replication. We will label our fingers polymerase to arrange free floating nucleotides that were cut apart on our tables. We will label glue sticks with ‘ligase’ labels and glued the free nucleotides to the original DNA strand (chromatids) to create 2 identical strands to the original strand. We practiced our knowledge on an in class worksheet. Next we discussed the mitotic phase of the cell cycle. The mitotic phase includes both mitosis and cytokinesis. We discussed what happened looked at a real life picture of a cell in that phase and used a color diagram handout to look at each phase. We used the acronym PMAT to help us remember the phases; prophase, metaphase, anaphase and telophase. During prophase spindle fibers connect to the centromere and chromosomes shorten and thicken. During metaphase, chromosomes line up in the 'middle' of the spindle. This will appear as chromosomes are two sister chromatids aligned at the equator of the cell. Anaphase is when the chromatids actually pull 'apart' and are separated. The chromosomes move to opposite sides of the cell. During telophase chromosomes begin to unravel and become chromatin again, nuclear envelope reassembles and there are two distinct nuceli as the cell begins to 'tear' apart. After mitosis, cytokinesis happens where we actually have created two complete cells. I had students identify each phase on a picture of cells going through mitosis.
Homework - None
Objectives - Students will use models to replicate DNA. Students will list and identify the phases of mitosis. Students will explain what happens during each phase of mitosis.