Module 5
1. Module 5
1.15. Page 4
Module 5—Cell Division: The Processes of Mitosis and Meiosis
Lesson Summary
During this lesson you explored the following focusing questions:
- How are the different phases of mitosis identified and described?
- How does mitosis maintain consistency in plants and animals?
Mitosis is the orderly separation of doubled chromosomes into new daughter cells. Through prophase, metaphase, anaphase, and telophase, the cell carefully ensures each new cell has a complete set of chromosomes. By undergoing this division, plant or animal tissue lines are continued faithfully until time and exposure to the environment cause a breakdown.
Lesson Glossary
Consult the glossary in the textbook for other definitions that you may need to complete your work.
anaphase: the third phase of mitosis where spindle fibres contract, pulling sister chromatids of each chromosome apart to opposite poles
centrioles: organizing bodies of the spindle
As they move apart in prophase, spindle fibres stretch out between them, forming the spindle apparatus.
kinetochore: another word for centromere; the small body holding the sister chromatids together as one chromosome; attaches to a spindle fibre at the metaphase plate
metaphase: the second phase of mitosis where chromosomes line up on the equator (metaphase plate) and attach via their centromeres to a spindle fibre
Each centromere replicates so each sister chromatid has its own to allow spindle fibre to attach.
prophase: the first phase of mitosis where visible chromosomes appear scattered through a cell; nuclear membrane dissolves; centrioles move to opposite poles, forming a spindle between them
telomere: a section on each end of a chromosome that shortens with each mitotic division
If the telomere is too short, the cell no longer divides.
telophase: the fourth phase of mitosis where nuclear membranes form around the two groups of chromosomes; spindle apparatus dissolves; chromosomes decondense to become chromatin