Biology



Chapter 10 Cell Growth and Division Pp 240 Two reasons why cells divide instead of growing bigger: 1. More demands are placed on the cell’s DNA. There is only so much genetic info available when the cell first forms. Larger cell means more organelles. 2. Cell has trouble moving nutrients and wastes across the cell membrane. //Ratio of surface area to volume. Volume increases faster than surface area// Cell Division  -    ** Process by which a cell divides into two new “daughter” cells **  -    Genetic material is duplicated before the cell divides  -    Cell size is reduced, increasing surface area to volume ratio Chromosomes  -    Carry genetic information from one generation of cells to the next. Made up of DNA  -    Only visible during cell division o  Fruit fly cells- 8 chromosomes o  Carrot cells- 18 chromosomes o  Human cells- 46 chromosomes  -    Chromatids- chromosomes are copied Cell Cycle  -    Events that cells go through as they grow and divide: o  Grows o  Prepares for division o  Divides o  From two daughter cells o  Begins cycle again  -    Four phases: o  “M” (mitosis) cell division o  “G1” Cell Growth o  “S” DNA replication o  “G2” Prepare for mitosis Cell Cycle Interphase Cell Division Mitosis Cytokinesis Prophase Metaphase Anaphase Cyclin Cancer Telophase Centriole Spindle Centromere  -    All types of cells in the body come from a single fertilized cell  -    Some cells do not specialize, these are Stem Cells. These can be collected from embryos or even the umbilical cord at birth.  -    Many types of cells in your body cannot reproduce themselves after being injured or damaged  -    Implanted stem cells into these damaged cells may be able to “heal” or re-grow these cells
 * Stem Cells **

Interphase 3/4 of cell cycle

 -  Down Syndrome- o  Trisomy 21 (3 on pr. 21) o  Flat face, folds around eyes, mental retardation, low muscle tone  -  Turner Syndrome- o  Monosomy x (x chromosome completely or partially missing  o   Female, heart problems, short, kidney problems, infertile  -   Klinefelter Syndrome-  o   Trisomy XXY  o   Male, round body, shape, tall, breasts develop, small testes, reading/writing problems

Genetic Engineering Ch 13  -  Transgenic- contain genes from other organisms <span style="mso-fareast-font-family: Calibri; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri; mso-bidi-font-family: Calibri;"> -  Cloning- organisms with identical genetic information Ex. Identical twins, plant cuttings, Dolly the sheep <span style="mso-fareast-font-family: Calibri; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri; mso-bidi-font-family: Calibri;"> -  Recombinant DNA- combining DNA from 2 sources. Ex production of insulin from humans and bacteria cells <span style="mso-fareast-font-family: Calibri; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri; mso-bidi-font-family: Calibri;"> -  Gene Therapy- cures genetic disorders by splicing a normal gene into harmless virus that is inserted into a defective cell to correct a defect. Treat cystic fibrosis, hemophilia, AIDS, and several forms of cancer