IV. Controlling the Cell Cycle- 3 "checkpoints"
    A. G1 Checkpoint- at end. Is it ready to replicate the DNA?
    B. G2 Checkpoint- at end. Had the DNA replicated correctly?
    DNA polynerases (enzymes) assess and repair "damage" to DNA.
    C. M Checkpoint- Had the DNA separated correctly? If yes, Cytokinesis finishes the process; if no, the cell/s will undergo a programed cell death.
V. Cancer and the Cell Cycle- an uncontrolled growth of cells is a cancerous tumor. 2 types:
    A. Benign- Encapsulated- contained within a membrane. Most can be surgically removed.
    B. Malignant- Non-encapsulated- invasive- can spread into ANY part of the body- Metastis- when the malignancy spreads to another tissue or organ.
    C. Mutations in 2 types of genes are dangerous in term of Cancer.
        1. Proto-oncogene- Code for proteins that simulate cell division. Activated, or not, at the G1 Checkpoint. If mutated they might become Oncogenes- Automatically be activated no matter what. (Bad)
        2. Tumor-suppressor Genes- Inhibit cell division
          P53- Monitors the integrity of DNA. If the protein is damaged, the protein stops cell division and stimulated repair. Will simulate PCD (programed cell death) if the damage is beyond repair. (Good if it isn't mutated)