Mitosis and Cancer Chapter 5, Section 2 In your textbook
Prophase Nuclear envelope disintegrates Chromosomes condense Centrioles – paired structures that produce spindle fibers – begin moving toward opposite poles (sides) of the cell Video clip Video clip – 3:47
Metaphase Chromosomes line up along the equator (midline) of the cell Spindle fibers extend from centrioles and attach to chromosomes at the centromere Video clip Video clip – 0:28
Anaphase Spindle fibers separate chromosomes at the centromere and pull sister chromatids to opposite poles of the cell Video clip Video clip – 0:38
Telophase Nuclear envelopes form around each set of genetic material Spindle fibers disappear Cytoplasm may begin to pinch in near the center of the cell (the mechanism for this is different in plants than animals) Video clip Video clip – 1:13
Cytokinesis the division of the cytoplasm – almost always follows telophase. differences in cytokinesis between plant and animal cells because of the cell wall in plants (animal cells only have a cell membrane).
Occurs when cells begin to divide uncontrollably Cancer
Cancer (cont’d) In normal tissue, there is a balance between new cell growth and old cell death. In cancer cells, that balance is disrupted – so a growing mass of tissue develops This mass of tissue is called a tumor. Benign = non-cancerous Malignant = cancerous Video clip – 3:10 Video clip Video clip
Cancer (cont’d) Malignant (cancerous) tumors are dangerous because they can: invade the organs interfere with the functions of these organs.
Types of Cancer Carcinomas = most common types; arise from the cells that cover external and internal body surfaces. Ex: Lung, breast, colon Sarcomas = arise from cells found in the supporting tissues of the body. Ex: bone, cartilage, fat, connective tissue, and muscle.
Types of Cancer, cont’d Lymphomas = cancers that arise in the lymph nodes and tissues of the body's immune system. Leukemias = cancers of the immature blood cells that grow in the bone marrow.