Cell Growth and Division by lwTsR5c

VIEWS: 10 PAGES: 11

									Cell Growth and Division

  The cell cycle and Mitosis.
                   When to Divide?
• Diffusion is a limiting factor
    – Works well over short distances
    – Takes too long to travel far

• Surface area to volume ratio
    – All nutrients and waste must cross the cell membrane
    – Larger the cell the smaller the surface area to volume ratio
    (A larger cell produces more waste, but has less surface area for it to get
       out of)

• DNA is a limiting factor
    – Most cells have 1 nucleus and 1 set of DNA
    – If the cell is too Big one copy of the DNA is not enough to make enough
      proteins for a large cell
       Diffusion and cell size
• Materials move through cells by diffusion.
  Oxygen and food move into cells, while
  waste products move out of cells.
• The size of a cell affects how efficiently
  materials get to all parts of a cell.
• The larger the cell the less efficient
  transport of materials across the cell
  membrane is.
   Surface area to Volume Ratio



 Surface Area
 (length x width x 6)
 Volume
 (length x width x height)
 Ratio of Surface Area
 to Volume



• The higher the surface area to volume ratio the
  easier it is to get nutrients to the cell
      Prokaryotic cell division
• Binary fission
• DNA replicates
• No organelles to multiply
• Cell divides cytoplasm, ribosomes and
  DNA
• Cell wall divides two cells
          The Cell Cycle


                 G1 phase




M phase

                            S phase



             G2 phase
                Interphase
• Interphase is when the cell is not dividing,
  but is going about its normal daily
  business. Ex. Nerve cells send
  messages, muscle cells contract.
  – G1- cell growth and day to day life
  – S -Synthesis- DNA is replicating
  – G2 –prepare for cell division, make extra
    copies of organelles so both daughter cells
    will get all the organelles.
              Root words
• Look up what the following word pre-fixes
  mean
• Inter-
• Pro-
• Meta-
• Ana-
• Telo-
      Root Words… Defined
• Inter-Between, the cell is between
  divisions
• Pro-Greek, from pro, before, before cells
  divide they must prepare.
• Meta-Greek, from meta, beside,
  Chromosomes are side by side
• Ana- Backward, Chromosomes are pulled
  back
• Telo-From Greek telos, end
                             Correct order…
                           Interphase                   Prophase
                                                    Spindle
                                                    forming
              Centrioles


                           Nuclear                   Centromere                         Centriole
                                        Chromatin
Cytokinesis               envelope                                  Chromosomes
                                                                  (paired chromatids)
                                                                       Spindle
                                                                                                    Metaphase
                                                                       Centriole

                                                 Individual
                                               chromosomes


               Nuclear
              envelope
              reforming
                                                                         Anaphase

                          Telophase

								
To top