NOTES The Cell Cycle

Today’s agenda: Review cancer Review Mitosis DNA worksheet Work from book: page 165 = Homework (or finish in class)

The Cell Cycle The cell cycle is broken into three main components: Interphase Mitosis Cytokinesis

Interphase The longest portion of the cell cycle. During this phase, the cell increases in size and makes the proteins necessary for the cell to function. Some organelles start to duplicate.

Replication Towards the end of Interphase, some organelles start to duplicate, and the DNA begins to uncoil or unzip itself to make a duplicate copy of DNA.

End of Interphase The cell continues to grow. Chromatin is still in its loosely coiled form. Mitochondrias duplicate.

Activity – DNA sheet

Mitosis

First things first… A few groups are still missing presentations. Presentations will resume today (lunch) and tomorrow. Microscope booklet – Due last week Cell lab sheet – Due last week (extras in the bin)

Today: Review Mitosis Introduction to asexual reproduction

Mitosis I – PMAT -- What does that stand for? Interphase Prophase Metaphase Anaphase Telophase

The Beginning – Interphase Original Cell Well, more like this…

End of Interphase Cell with Replicated Chromosome and Organelles Still looks like this…

What is Mitosis? Mitosis is the process by which a parent cell divides into two identical daughter cells. Sometimes, there are errors during this process which will result in genetic anomalies. During this process, replicated chromosomes (which are actually two chromatids held together by a centromere) are separated and divided into two Daughter Cells.

Prophase Two centrioles nuclear wall nucleolus Early Prophase: Replicated Chromosomes coil up Nucleolus disappears Nuclear membrane begins to break down Centrioles are moving towards poles ______________ fibers? Late Prophase: Spindle fibers complete Chromosomes attach to spindle fibers at their ______________________ Nuclear membrane disappears

Metaphase Spindle Fibers centromere Tugging action of spindle fibers pulls X-shaped chromosomes into a single line across the middle of the cell.

Anaphase Spindle fibers contract Chromosomes split at centromeres Sister chromatids are pulled to opposite sides of cell

Telophase A complete set of chromosomes is on each side of the cell Spindle fibers disappear Nuclear membrane forms Nucleolus reappears One cell, two nuclei = the cell is ready to divide!

Cytokinesis Cell pinching: the swollen cell begins to pinch at the equator, separating the cytoplasm and its contents into two new cells. Daughter Cells – Identical to parent cell What are these called?

Show what you know worksheet

Asexual Reproduction Asexual reproduction: Only one parent is required, and the offspring is a genetic copy to the parent, or a clone. Bread mould, for instance, is a group of cloned cells from a single mould spore. A new duplicate tree growing up from the bottom of another tree is also a clone. How about animals?

Cloning Animals – Mimi

Cloning Worksheet – Work in pairs