Cell growth and Reproduction

1
Cell growth and Reproduction

• Though there are exceptions in cell size
• nerve cells reaching 1 meter
• Ostrich egg measuring 8 cm most cells are between
  2-200 nanometers (thats too small to see without
  a microscope)
• Why are cells the size they are?
• Diffusion

2
What limits the cell size

• DNA
• Surface to volume ratio

3
Cell Reproduction

• Remember the cell theory? all cells ---
• Come from preexisting cells
• Cell division results in two IDENTICAL cells
• This way we can grow and change and even though
  our cells split we are still the same person

http//www.cellsalive.com/howbig.htm
4
Chromosomes Chroma-coloredStroma-body

• Contain DNA
• Become darkly colored when stained
• Vanish after cell division
• They are the carriers of the genetic material
  that is copied and passed on generation to
  generation

5
Structure of eukaryotic chromosomes

• Chromatin-
• long strands of DNA wrapped around proteins
  called histones
• Grouped together they make up they form a
  chromatin
• So things stay organized during division they
  coil up to form chromosomes

6
Structure of eukaryotic chromosomes
7
Chromosome Structure
8
Cell cycle

• the sequence of growth and division of a cell
• Can be divided into two periods
• Period of growth
• Period of division
• Most of the cells life is spent in
• Interphase (PERIOD OF GROWTH)
• Grows, carries on metabolism, and the big part
• CHROMOSOMES ARE DUPLICATED
• MITOSIS -Cell goes through a series of steps to
  produce TWO identical calls (period of division)

9
Mitosis
10
Web link

• http//www.biology.arizona.edu/cell_bio/activities
  /cell_cycle/cell_cycle.html

11
Root tip

• http//bio.rutgers.edu/gb101/lab2_mitosis/highmag
  root1.html

12
Cytokinesis

• In cytokinesis the cells cytoplasm divides
• Is this a plant or animal cell?
• Why?