1.Biology Cell Reproduction Notes

2.

New cells are created in your body every day.Think of three reasons why your body might need new cells.

3.

Unicellular organisms - asexual reproduction

Multicellular organisms- growth & repair.

4. 5. Cell Cycle

Interphase- the longest part of the cell cycle: growth, metabolism & preparation for division occurs. Chromosomes are replicated. (S phase)

Mitosis -the division of the nucleus.

Cytokinesis-the division of the cytoplasm.

6. The Steps of Mitosis

PMAT (remember the order that they occur)

Mitosis produces two cells with the same number of chromosomes.

7. Prophase (Preparing)

Longest phase of mitosis

Nuclear envelope & nucleous disappears.

Chromosomes become visible.

Centrioles (animal cell) form and move to opposite poles of cell

Spindle fibers form from centrioles, cross cell and attach to the chromosomes.

8. Metaphase (middle)

Chromosomes line up in themiddleof the cell.

Spindles are attached to them.

9. Anaphase (Apart)

Spindle fibers begin to shorten.

This pulls chromosomes apart.

Chromosome halves are now referred to as chromatids.

10. Telophase (Two cells)

Chromatids reach poles.

Chromosomes become chromatin.

Spindle fibers break down.

Nucleolus and nuclear envelope appear.

11. Cytokinesis(happens during telophase)

Division of cytoplasm

In animal cells: cell membrane continues to pinch in until two cells are formed

In plant cells: cell plate forms in center of cell and eventually splits cells

At the end of mitosis, two new daughter cells are produced.