The document discusses the cell cycle and cell reproduction. It describes the main stages as interphase, where the cell grows and prepares for division, and the M phase where the nucleus and cell divide. Interphase includes the G1, S, and G2 phases where the cell makes proteins, organelles and replicates DNA. The M phase consists of mitosis, where the nucleus divides, and cytokinesis, where the cell splits into two. Mitosis is further broken down into the prophase, metaphase, anaphase and telophase stages where the chromosomes align and separate. Cytokinesis differs in animal and plant cells in how the cell membrane pinches or a cell plate forms to divide the cell. The result of

1. The Cell Cycle &
Cell Reproduction
Intro Animation

2. • Reproduction
– A single-celled organism can divide to become two
living organisms (next generation of the species)
– A multicellular organism can grow from a single
cell created by fertilization (zygote)
• Growth
– Division of a single cell can result in numerous
cells
– DNA is passed from one cellular generation to the
next
• Repair
– Damaged cells can repair themselves as they
spend time in interphase

5. This amoeba is undergoing cell division to create a
genetically identical daughter cell.

6. Paramecium

7. These dividing bone marrow stem
cells are undergoing mitosis to give
rise to new blood cells

8. • The cell cycle (in eukaryotes)
• Includes two MAIN stages…
1. Interphase = cell growth,
metabolism, replication of DNA,
preparation for cell division
2. M Phase = nuclear division and
splitting of the cytoplasm/cell

10. Interphase
• The period of time before M Phase
• Interphase is divided into 3 phases: G1,
S, and G2.
• Proteins are made, organelles are
constructed, DNA is replicated, and
materials needed for cell division are
produced.

12. The M Phase: Mitosis
and Cytokinesis
• Mitosis- the process by which the nucleus
of the cell divides into two nuclei, each
with the same number and kinds of
chromosomes as the parent cell.
• Cytokinesis- the process by which the
cytoplasm divides and the cell splits,
forming two cells.

14. Four Phases of Mitosis
•Prophase
•Metaphase
•Anaphase
•Telophase

18. Early Prophase
• Centriole pairs move
toward opposite
poles (animal cells)
• Spindle fibers begin
to extend from
centrioles. Form
asters
• Duplicated
chromosomes form
as long threads

20. Late Prophase
• Nuclear membrane breaks down
• Nucleolus disappears
• Chromosomes clearly visible and begin to
move to equator of cell

22. Metaphase
•Spindle fibers align the chromosomes along
the middle of the cell nucleus. (metaphase
plate)
•At the end of this stage, sister chromatids
(aka. chromosomes) begin to separate

25. Anaphase
Early Anaphase:
Sister chromatids separate and move to opposite
sides of the cell.
Late Anaphase
Sister chromatids move to poles

29. • Centrioles and spindle fibers
disappear
• Chromosomes begin to
stretch out/become
uncondensed
• Cleavage furrow/cell plate
begins to form

30. Telophase
• New membranes form around the
chromatids forming daughter nuclei.

32. Cytokinesis: Animal vs. Plant Cells
• Cytokinesis in animal
cells begins with the
formation of a cleavage
furrow
• This is the site at which
the cytoplasm is divided
between the 2
• The cleavage furrow
appears during telophase
• Contractile ring pinches
cell in two

33. Cytokinesis: Animal vs. Plant Cells
• Cytokinesis is quite
different in plant cells
• During telophase, a new
cell wall begins to form at
the metaphase plate
• This is called a cell plate
• The plant cell continues
to grow this cell wall until
it divides the cell into 2

34. Results of Mitosis
•Mitosis is the division of a NUCLEUS
•Mitosis produces two new nuclei that have the SAME
number of chromosomes as the original nucleus.
•MITOSIS IS ASEXUAL
ONE PARENT = 2 IDENTICAL DAUGHTER CELLS
Mitosis Animation