AP Biology The Cell Cycle Part 2

Centrioles

Interphase

Before and after the S phase

Interphase cell (Look at the chromatin in the blue nucleus and the yellow cytoskeleton.)

Start of Mitosis

Cell in Prophase

Mitosis “Division of the nucleus”

Cell in Metaphase

Cell in Anaphase

Cell in Telophase and starting Cytokinesis

One cell becoming two

Motor Protein and the Spindle Fibers Chromosome movement Kinetochore Tubulin subunits Motor protein Microtubule Chromosome

Animal vs. Plant

LE 12-10 Chromatin condensing Nucleus Chromosomes Cell plate 10 µm Nucleolus Prophase. The chromatin is condensing. The nucleolus is beginning to disappear. Although not yet visible in the micrograph, the mitotic spindle is starting to form. Prometaphase. We now see discrete chromosomes; each consists of two identical sister chromatids. Later in prometaphase, the nuclear envelope will fragment. Metaphase. The spindle is complete, and the chromosomes, attached to microtubules at their kinetochores, are all at the metaphase plate. Anaphase. The chromatids of each chromosome have separated, and the daughter chromosomes are moving to the ends of the cell as their kinetochore micro- tubules shorten. Telophase. Daughter nuclei are forming. Meanwhile, cytokinesis has started: The cell plate, which will divide the cytoplasm in two, is growing toward the perimeter of the parent cell.

Microscopic view of Mitosis in Onion root tips Microscopic view of Mitosis in Onion root tips. Can you identify the stages?

Checkpoints (Is all going according to plan?)