The document discusses how multicellular organisms grow. It states that growth occurs through cell division, not by individual cells increasing in size. It also notes that for binary fission to occur in bacteria, the cell must grow in size and duplicate its DNA so that each new cell has its own copy.

1.  Multicellularity
 We all start out as
a single cell
 Key Concept:
Growth occurs when
more cells are
made, NOT
because cells get
bigger.

6.  What happens to the size of bacteria
after binary fission?
 What two things have to happen
before fission occurs?

7.  What happens to the size of bacteria
after binary fission?
 What two things have to happen
before fission occurs?
› A. Cell must grow in size before splitting
again.
› B. Cell must duplicate its DNA, so each
new cell will have its own copy.

8. Scientifically speaking, how do little elephants
grow up to be BIG elephants?
Write your answer in your
Quickstart!

10. Skin cancer - the abnormal growth of
skin cells - most often develops on skin
exposed to the sun.
Cell that reproduce by asexual
reproduction reproduce constantly.

11. Animated Mitosis Cycle
http://www.cellsalive.com/mitosis.htm
The cell life cycle consists of:
• Interphase
• Prophase
• Metaphase
• Anaphase
•http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0
Telophase & Cytokinesis

12. • Chromosomes are copied (# doubles)
• Chromosomes appear as threadlike coils
(chromatin) at the start, but each chromosome
and its copy(sister chromosome) change to sister
chromatids at end of this phase
CELL
Nucleus MEMBRANE
Cytoplasm

13. Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

14. • Mitosis begins (cell begins to divide)
• Centrioles (or poles) appear and begin to
move to opposite end of the cell.
• Spindle fibers form between the poles.
Centrioles
Sister chromatids
Spindle fibers

15. Animal Cell Plant Cell
Spindle fibers
Centrioles
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

16. • Chromatids (or pairs of chromosomes) attach
to the spindle fibers.
Centrioles
Spindle fibers

17. Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

18. • Chromatids (or pairs of chromosomes)
separate and begin to move to opposite
ends of the cell.
Centrioles
Spindle fibers

19. Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

20. • Two new nuclei form.
• Chromosomes appear as chromatin (threads
rather than rods).
• Mitosis ends.
Nuclei Nuclei
Chromatin

21. Animal Cell Plant Cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

22. • Cell membrane moves inward to create two
daughter cells – each with its own nucleus
with identical chromosomes.

23. Animal Mitosis -- Review
Interphase Prophase
Metaphase Anaphase
Telophase Interphase

24. Plant Mitosis -- Review
Interphase Prophase
Metaphase Anaphase
Telophase Interphase

25. 26

26. - Cell Division
27 27

27. http://www.cellsalive.com/mitosis.htm