Chapter 8

Questions:

What are the phases of mitosis ?

First is interphase which lasts the longest time (about 90% of cell's life cycle) during this phase cell performs normal actions. Also this p

hase is divided into 3 sub-phases G1, S (division of DNA), G2. After interphase prophase follows. During prophase cell looses the nucleus and chromosomes become visible. Then there's prometaphase during this phase spindle is created. At metaphase chromosomes align on the metaphase plate. Then during anaphase the chromosomes separate and move toward the pole's of the cell. Telophase is finishing up the division and cytokinesis divides cytoplasm.

What is the difference between cytokinesis and mitosis ?

Cytokinesis represents the process of cytoplasmic division. Also during cytokinesis the cell finally separates into two daughter cells. On the other hand mitosis represents only the division of nucleus and chromosomes.

What is the difference between the products of Mitosis and Meiosis ?

The main difference between the products of Meiosis and Mitosis is that Meiosis produces cells with haploid number of chromosomes (23 for humans); Meiosis leads into creation of four daughter cells not two and these four cells are sex cells (sperm and egg).

Diagram:

This diagram shows Mitosis. The process and sub phases of Mitosis are described in Question 1.

5facts :

Mitosis is cell division.

Due to cross overs during Meiosis the daughter cells have different genetic variation than parent cells.

Meiosis produces four haploid cells and mitosis produces two diploid cells.

Karyotype is display of magnified images that helps the doctor diagnose any chromosomal diseases.

Down's syndrome is one of the most common chromosome number abnormality.

Key terms :

Karyotype - display of magnified images of an individual's chromosomes

Genetic recombination - the production of gene combinations different from those carried by the original chromosomes

Diploid cells - cells with two homologous sets of chromosomes

Haploid cells - cells with a single chromosome set

Fertilization - process when egg and sperm fuse together

Zygote - the resulting fertilized egg

Sex chromosomes - X and Y chromosomes

Autosomes - 22 pairs of chromosomes (sex chromosomes are not included)

Somatic cell - typical cell in human body

Tumor - an abnormally growing mass of body cells

Video :

Mitosis

Summarize : Chapter 8 was presenting Mitosis and Meiosis. The process of cell reproduction and also the abnormalities that can arise from mistakes during the cell division.