The Cell Cycle Mitosis and Cancer Glencoe Biology

The Cell Cycle, Mitosis, and Cancer Glencoe Biology Chapter

What causes cancer? • Cancer is caused by mutations which creates abnormal cell growth. • A mutation is a change to an organism’s DNA.

What causes mutations? (changes our DNA? ) • Radiation • UV radiation • X rays • Chemicals • Alcohol • Tobacco • Drugs • Infectious agents • Viruses like HPV

Genetic Material • During most of the cell’s life, genetic material exists in chromatin • Chromatin = DNA that is long and tangled • Chromatin coils up (during M phase) to form chromosomes • When UNCOILED, chromatin makes proteins and can replicate itself • When COILED, cell division can occur

Anatomy of a Chromosome

The Cell Cycle INTERPHASE S (DNA synthesis) G 1 s si ito t Cy s i es n i ok M • The growth period is called INTERPHASE • The stage during which the cell carries out cellular functions • Also the stage in which it grows and replicates its DNA. MI (M) TOTIC PH AS E G 2

The Cell Cycle S (DNA synthesis) G 1 is si ito t Cy i ok s s ne M • The nuclear division period is called M PHASE (Mitosis) • the stage of the cell cycle during which the cell’s nucleus and genetic material divide. • Consists of Prophase, Metaphase, Anaphase, and Telophase (PMAT) INTERPHASE MI (M) TOTIC PH AS E G 2

The Cell Cycle • The cytoplasmic division period is called CYTOKINESIS S (DNA synthesis) G 1 s si ito t Cy s i es n i ok M • The method by which a cell’s cytoplasm divides, creating a new cell. INTERPHASE MI (M) TOTIC PH AS E G 2

Why do cells need to divide? • REPRODUCTION in UNICELLULAR organisms • Development, Growth, and Repair in SOMATIC (body) cells

INTERPHASE – BEFORE MITOSIS centrioles chromatin Nuclear membrane

1 st stage of Mitosis: Prophase During Prophase… • Chromatin coils up into visible chromosomes centrioles chromosomes • The nucleus will disappear during this phase Nuclear membrane • Centrioles will begin to separate

2 nd Stage of Mitosis: Metaphase During Metaphase… • Spindle fibers pull the chromosomes to the middle (equator/metaphase plate) of the cell

3 rd stage of Mitosis: Anaphase During Anaphase… • Chromosomes will be pulled apart forming chromatids. • Once the chromatids are separated, they will move towards opposite sides of the cell.

4 th stage of Mitosis: Telophase During Telophase… • The chromatids uncoil, becoming chromatin • The nuclear envelope reforms • Mitosis is COMPLETE!!!

Cytokinesis: last stage in the cell cycle • The cytoplasm divides into two new cells. • ANIMAL CELLS: The cell membrane will move inward and pinch apart • PLANT CELLS: A new cell wall (cell plate) forms between the two new cells.

SUMMARY - MITOSIS • • Number of ROUNDS of cell divisions: 1 Number of daughter cells : 2 Genetically identical? Yes Chromosome #: Same as parent Where: Somatic cells (non-sex cells) When: Throughout life Role: Growth and repair

The complete CELL CYLCLE cell cycle video M-PHASE (mitosis + cytokinesis) MITOSIS

KARYOTYPE and Chromosome Number: • Human chromosome number: • 46 in body (somatic) cells (diploid OR 2 N) • 23 in sex cells (egg and sperm) (haploid OR N) A picture of species’ full set of chromosomes is a KARYOTYPE

INTERPHASE S (DNA synthesis) G 1 MI (M) TOTIC PH AS E ito M Cy si i k to s s si e n G 2