Unit 4: Cancer, Cell Cycle, Mitosis, Meiosis Study Guide

Unit 4: Cancer, Cell Cycle, Mitosis, Meiosis Study Guide

Cancer is caused by mutations which create abnormal cell growth

Mutations can be caused by radiation, chemicals, can be inherited, or caused by viruses

coiled DNA, or chromosome

uncoiled DNA, or chromatin

homologous chromosomes (pair) sister chromatids (“arms” of chromosome)

The Cell Cycle:

Has two main steps:

Interphase: G1, S, G2 (G= growth, S = DNA synthesis)

M-Phase: Mitosis + Cytokinesis (Mitosis = nuclear division; cytokinesis = cytoplasm division)

Mitosis:

Purpose: growth and repair, asexual reproduction (Binary Fission: asexual reproduction in BACTERIA - using Mitosis)

End result: 2 genetically identical cells (diploid)

Types of Cells that do Mitosis: body (somatic) cells, bacteria (in binary fission)

Stages of Mitosis: PMAT (Prophase, Metaphase, Anaphase, Telophase)

Number of cycles of division: 1

Main events in PMAT:

Prophase: chromosomes condense, nucleus/nucleoli disappears, spindle fibers form.

Note: spindle fibers attach to chromosomes and move them to opposite poles of the cell.

Metaphase (meta = middle): chromosomes move to the middle of the cell

Anaphase (ana = apart): chromatids (chromosome arms) are moved apart.

Telophase (the “binocular” stage): chromosomes uncoil back to chromatin

Cytokinesis: cytoplasm divides

IN plant cells: Cell Plate(a new cell wall) is made between two daughter cells

Meiosis:

Purpose: to produce sex cells (gametes): egg and sperm.

End result: 4 genetically different cells (haploid)

Types of Cells that do Meiosis: cells present inside reproductive organs of humans: cells in testicles produce sperm; cells in ovaries produce eggs

Stages of Meiosis:Meiosis 1 (PMAT 1) and Meiosis 2 (PMAT 2). These cycles are continuous as the cells in Meiosis 1 keep on dividing during Meiosis 2.

Number of cycles of division: 2 (Meiosis 1 and Meiosis 2)

Main events in PMAT1:

Prophase 1: crossing over (exchange of DNA pieces)

Anaphase 1: Pairs of chromosomes (homologous chromosomes) get separated

Meiosis 1 results in 2 genetically different, haploid cells

Main events in PMAT2:

Anaphase 2: chromatids (the “arms” of individual chromosomes) get separated

Meiosis 2 results in 4 genetically different, haploid cells

MITOSIS

TWO IDENTICAL DAUGHTER CELLS

MEIOSIS