Cell Cycle Interphase, Mitosis, Cancer, and Cell Size © PicScience LLC 2011

cell divides and creates 2 identical daughter cells; cell reproduction Three types: 1.Prokaryotes – for reproduction 2.Eukaryotes – for growth and repair 3.Gametes – makes sex cells

How do the types of division differ? Prokaryotic division-cells reproduce by binary fission: Cell’s genetic information (chromosomes) is copied, cell divides in two, each cell is identical to parent cell Eukaryotic division-parent cell makes copy of its chromosomes before it divides. Gametes made by meiosis. DNA replication Chromosome segregation Cytokinesis Diploid cell S S-phase gametes zygote +

Cell Cycle—sequence of growth and division that a eukaryotic cell undergoes Two parts: 1) Interphase 2) Mitosis Interphase—1 st phase; busiest and most time consuming part of cell cycle

1) Interphase 3 phases: G1 phase- cell growth, protein production S phase-chromosomes copied (DNA synthesis), creates 2 sister chromatids G2 phase-cell prepares to divide, new organelles form

2) Mitosis Mitosis-nucleus of cell divides to form 2 nuclei ▫-ensures that each new cell will have a copy of every chromosome Cytokinesis- division of cell cytoplasm, follows mitosis

Mitosis 4 main phases: ▫Prophase ▫Metaphase ▫Anaphase ▫Telophase

Summary Cell division InterphaseG1SG2MitosisProphaseMetaphaseAnaphaseTelephase

What happens if cells divide too much?

Cancer Form masses of cells called tumors which deprive normal cells of nutrients Spread freely because they lack surface proteins Have abnormal size, shape, and abilities

Cancer

Cell Size Cells come in all sizes from very small to very large Examples: nerve cell 1 micrometer (millionth of a meter) Ostrich yolk 8 cm in width

Why is cell size limited? 1.) the smaller the cell the easier and less time it takes for diffusion of substances such as oxygen to reach the mitochondria; site of cellular respiration and production of ATP can occur

2.) cells DNA also limits the size of the cell. If a cell doesn’t have enough DNA to program its metabolism (all the chemical reactions that occur in an organism) it cannot live. Large cells often have more than one nucleus providing more DNA.

1.) Which of the following occurs during binary fission? A.) two genetically identical cells are produced B.) a cell grows as large as it can C.) The nucleus of as cell divides into two nuclei D.) a cell develops a second cell membrane Review

2.) In which phase of the eukaryotic cell cycle is the genetic material duplicated? A.) G1 phase B.) S phase C.) G2 phase D.) M phase

Review 3.) Which 2 phases of the cell cycle make up cell division? A.) telophase and cytokinesis B.) mitosis and cytokinesis C.) interphase and mitosis D.) cytokinesis and interphase

Review 4.) What happens in prophase? A.) sister chromatids line up at center of the cell B.) sister chromatids start to separate C.) sister chromatids are formed D.) the cell splits in two

Review 5.) What are masses of cancerous uncontrollable cell growth called? A.) cysts B.) nodules C.) tumors D.) T cells

Review 6.) cancer spreads easily b/c they lack A.) mitochondria B.) cell membranes C.) inhibitor growth genes D.) surface proteins