Cell Division: Mitosis & Cytokinesis

The Cell Theory says… All living things are made of one or more cells. The cell is the basic unit of structure and function. Cells come from other cells… (by cell division).

How does one cell turn into two cells?

Here are a fruit fly’s 8 chromosomesin the nucleus. What is one observation you can make? The chromosomes are all double copies of each other.

Matching chromosomes are called homologous chromosomes.

Why do organisms have two of each chromosome?

A CELL DIVISION RIDDLE… A fruit fly cell has 4 pairs of chromosomes. This cell divides into two cells. Each of the two cells has 4 pairs of chromosomes. How is this possible?

This reminds them that each chromosome has genes – specifically connects the fruit fly chromosomes to the fruit fly genes. Point out a few, also point out that the centromeres of the little ones are not in the center – long arm / short arm, chromosomes are different sizes

Emphasize that genes are on chromosomes, each chromatid is identical (has the same exact genes), and when cells divide, one chromatid travels to each cell with all the information.

Interphase ____phase (cell enlarges, organelles made, gene expression), ____phase (DNA replicates), ____phase (cell grows). DNA is in the form of ___________, __________________ is visible, __________________ is visible

Interphase _G1__ phase (cell enlarges, organelles made, gene expression), _S_ phase (DNA replicates), _G2__phase (cell grows). DNA is in the form of _chromatin__, __Nucleolus__ is visible, __Nuclear membrane______ is visible

Prophase -Chromosomes _________, -Nucleolus _____________, -Centrioles move to ______________of the cell, -Spindle fibers __________,

Prophase Chromosomes condense, - Nucleolus disappears, Centrioles move to opposite sides of the cell, - Spindle fibers start to form.

Metaphase Spindle fibers _____________chromosomes, Chromosomes line up _______________of the cell.

Metaphase Spindle fibers attach to chromosomes, Chromosomes line up in the middle of the cell.

Anaphase __________________ shorten, - Sister chromatids (or double chromosomes) _________________ to opposite poles.

Anaphase Spindle fibers shorten, - Sister chromatids (or double chromosome) are pulled apart to opposite poles.

Telophase & Cytokinesis - Nuclear membrane _________________ , - Single chromosomes unravel to become unorganized again to form _________________ - Spindle fibers_____________________ - _____________________ happens.

Telophase & Cytokinesis - Nuclear membrane reforms, - Single chromosomes unravel to become unorganized again to form __chromatin___ - Spindle fibers dissolve, - Cytokinesis happens.

Interphase _G1__ phase (cell enlarges, organelles made, gene expression), _S_ phase (DNA replicates), _G2__phase (cell grows). DNA is in the form of _chromatin__, __Nucleolus__ is visible, __Nuclear membrane______ is visible