multicellular cells cell division test: thursday jan. 13 th cell division, mitosis, meiosis
TRANSCRIPT
MULTICELLULAR CELLS
CELL DIVISION
Test: Thursday Jan. 13th
Cell division, mitosis, meiosis
Multicellular Cells
Many celled organisms
Cells are specialized to perform particular functions (can begin as stem cells)
Cells tissue organs organ system
What is the same in all of these cells??DNA!!
CELL DIVISION
Causes: DNA Overload Repair Growth Surface area to volume ratio gets
too large
Cell Cycle (pg. 245)
1) Interphase2) Mitosis3) Cytokenesis
The Cell Cycle
Interphase
Cell spends about 90% of its time in interphase
GROWTH STAGES: G1 = normal growth S = DNA doubles (where mutations can
occur) G2 = organelles double
Cell contains large nucleus with visible nucleolus
Nuclear division (pgs. 246-248)
Mitosis
Phases of Mitosis…Prophase
Chromosomes become visible
Phases of Mitosis…Metaphase
Chromosomes line up
Phases of Mitosis…Anaphase
Chromosomes separate
Phases of Mitosis…Telophase
Two new identical cells form
PLANT vs.
cell plate forms
ANIMAL cleavage furrow forms
Cytokinesis-cytoplasmic division
Plant Animal
Fig. 12.9
Mitosis Video
http://www.sumanasinc.com/webcontent/animations/content/meiosis.html
Cancer
Uncontrolled cell growth
Read stem cell article on
page 293
N= haploid # of chromosomes found in egg or sperm (gametes) Humans n=23
2N
2N
2NDiploid(2N)
=regular chromo# found in body cells (somatic)
two identical daughter cellsMitosis only occurs in somatic
cells