Download CELL CYCLE AND CANCER TEST REVIEW Reasons the cell cycle

CELL CYCLE AND CANCER TEST REVIEW
1. Reasons the cell cycle happens:
a. Growth of organism occurs by adding more cells, not by enlarging cells.
b. Repair/replace old, damaged cells
c. Allows DNA to control functions/protection of the cell. Keeps the surface area/volume
ratio HIGH (6:1, 4:1, 3:1).
2. Responsibility (purpose, job, chore) of the cell cycle: To make sure each new cell has the same
genetic information as the original cell. The original cell is called the PARENT cell; the new cells
are called DAUGHTER cells.
3. Mitosis occurs in all body cells, better known as SOMATIC cells. Each somatic cell has two copies
of each kind of chromosome (p. 341 in your textbook). Cells with two copies of chromosomes
are known as DIPLOID cells; also known as 2n. (Sex cells, also known as GAMETES, have only one
set of chromosomes and are said to be HAPLOID.)
4. Some one-celled organisms undergo asexual reproduction (cell cycle) known as BINARY FISSION.
5. Other organisms can replace parts of their bodies through a mitotic process known as
REGENERATION.
6. Remember that no matter what number of chromosomes a parent cell has, the daughter cells
will have the same number. For example, a parent cell with 423 chromosomes will produce 2
daughter cells with 423 chromosomes each. A 2n parent will produce two daughter cells
containing 2n each.
7. The Cell Cycle is made of 3 parts: Interphase, M Stage (Prophase, Metaphase, Anaphase,
Telophase), and Cytokinesis.
a. Interphase—Cell spends most of its time in this stage.
i. G1—Regular growth. The DNA is in long threads known as CHROMATIN.
ii. S—Synthesis (DNA/Chromosomes duplicate, replicate, make a copy of
themselves) Chromosomes shorten and are made of two parts called sister
chromatids and held together by the centromere.
iii. G2—Cell continues to grow. Cell prepares for the M Stage (organelles including
the nucleus dissolve into the cytoplasm.)
b. M Stage—Prophase, Metaphase, Anaphase, Telophase. KNOW WHAT EACH OF THESE
LOOKS LIKE AND BE ABLE TO DESCRIBE WHAT IS HAPPENING. Words to be able to
identify in the pictures and descriptions are: CENTRIOLES, SPINDLE FIBERS (and the
smaller ASTER RAYS), SISTER CHROMATIDS, CENTROMERE, CLEAVAGE FURROWS, PLANT
CELL PLATES. This stage results in the division of the NUCLEUS AND THE
CHROMOSOMES.
c. CYTOKINESES—Results in the division of the CYTOPLASM and the formation of the two
daughter cells. The nucleus, nucleolus, and other organelles reappear; the
chromosomes lengthen, and the spindle fibers, aster rays, and centrioles disappear.
8. REMEMBER THAT SOME CELLS DO NOT UNDERGO THE CELL CYCLE ONCE THEY HAVE REACHED
MATURITY. BRAIN CELLS, NERVE CELLS, AND LIVER CELLS GO INTO GO STAGE (G NAUGHT)
WHERE THE CELL DOES NOT GROW; IT SIMPLY DOES ITS JOB.
9. CANCER is a disorder of the cell cycle. Normally a cell will stop growing once it touches other
cells. Cancer happens when a MUTATION in the DNA/chromosomes occurs. The mutation
causes uncontrolled cell growth. The cancer cells will keep healthy cells from getting the
nutrition they need resulting in death of the healthy cells. Cancer cells often break off and
spread through the body. This is called metastasis.
10. Sometimes cells will form groups of cells called tumors. Not all tumors are cancerous. Those
that are not cancerous are called benign tumors.