Chapter 10 Cell Growth & Division
Question of the Day What is the size of one individual cell - Plant & Animal? On average an animal cell is 10 m and a plant cell is 100m. 1 m = 1x10^-6m
10-1 Cell Growth How does a cell grow? Through mass & organelle production Problems with unlimited growth How big can a cell get before it gets bad? Materials are harder to exchange thru membranes if bigger Waste Products Oxygen Water
Ratio of Surface Area to Volume What are Surface Area (SA) & Volume (Vol)? Surface Area = L x W x 6 sides Volume = L x W x H High SA to Vol makes it easier to exchange things As the cell grows, SA and Vol get bigger Bigger cells, Ratio of SA to Vol gets smaller
Cell Division Before cell gets too big it divides Forms 2 daughter cells Two cells are identical copies Complete with DNA, organelle, cytoplasm & equal size
Types of Cell Division In Prokaryotes - Simple, 1 step division In Eukaryotes - Complex, 2 stages: Mitosis (nucleus divided) Cytokinesis (cytoplasm ÷)
Chromosomes What is a chromosome? What carries genetic information How many does a human have? 46 What forms when chromosome ÷ sister chromatids (identical) How are chromatids attached? Centromere
The Cell Cycle There are 4 phases to cell cycle 1st 3 are growing and duplicating & 4th is division 1st is G1 - (Growth) of Cell 2nd is S - (Synthesis) DNA duplication 3rd is G2 - (Growth) & Mitosis Prep 4th is M - (Mitosis) Cell Division
Cell Growth Phases Also called Interphase G1 - initial phase cell almost doubles in size S - 1/2 way thru chromosomes replicate G2 - prep for mitosis finishes growth, ready for mitosis Takes about 95% of the time for division
Mitosis (Cell Division) 4 Phases of Mitosis Prophase Longest phase centrioles, spindle appear, nucleus dissolves Metaphase Chromosomes lineup, spindles attach to centromere Anaphase Spindles pull chromatids apart Telophase 2 Nuclei reform around chromatids, spindles break Cytokinesis Organelles & cytoplasm split & cell membrane divides
10-3 Regulating Cell Cycle What controls cell division? Cyclins What are they? Protein that helps spindle form Regulates timing of cell cycle In 2 ways: Internally - proteins affect mitosis inside cell Need all chromosomes to be doubled & attached to spindle Externally - proteins that speed up, slow down mitosis outside Stimulate cell growth (cytoplasm, cell membrane, organelles)
Uncontrolled Cell Growth What is it called? Cancer Cells that don’t respond to growth stop signs What do groups of cancer cells form? Masses or Tumors What kind of cancers are there?
Stem Cells What are they? Unspecialized cells that can be changed into any cell. Why is it so controversial? Deals with embryonic cells usually.
Ch. 10 Review What are the essential questions? What is surface area to volume ratio? What is cell division/ cycle/mitosis? What are cell cycle regulators? What are cancer and stem cells?