Cell Division

1
Cell Division

• Mitosis

2
Cell Cycle

• Common to most living things
• Sequence of growth and division of a cell.

3
Cell Cycle

• Interphase
• Period of growth for a cell
• Majority of time spent in this phase (95)
• Grows in size
• Metabolic processes
• Chromosomes are duplicated
• Preparation for division

4
Cell Cycle

• Interphase
• 3 parts
• G1(Growth Stage 1)
• First growth phase.
• Protein production is high
• S (Synthesis Stage)
• Continues to grow
• Copies genetic material
• G2 (Growth Stage 2)
• Second Growth Phase
• Cell completes preparations for cell division
• Cytoplasmic Organelles are replicated

5
Concept map

• Fill in where Interphase belongs along with the
  different stages of interphase!

6
Cards ready!

• The cell cycle is a. the division of a cell
• b. the growth of a cell
• c. the death of a cell
• d. both A and B
• Which stage of interphase is DNA replicated?
• a. G1
• b. S
• c. G2
• d. G3
• Which of the following does not occur in
  interphase?
• a. metabolic processes
• b. growth
• c. cell division
• d. replication of cytoplasmic organelles

7
Cell Cycle

• Cell Division
• Mitosis
• Happens in ALL cells.
• Short amount of time (5)
• Occurs when cell reaches max size
• Four Major Stages
• Prophase
• Metaphase
• Anaphase
• Telophase

8
Mitosis

• Prophase (Early)
• First Phase
• Longest Phase
• Chromatin coils up to visible chromosomes
• Contains duplicate sister chromatid
• Held together by centromeres
• Each are exact copies

9
Mitosis

• Prophase (Early)
• Nucleus begins to disappear
• Nucleolus and nuclear envelope disintegrate

10
Mitosis

• Prophase (Late)
• Nucleolus and nuclear envelope are gone
• Centrioles
• Normally outside of nucleus
• Now migrate to opposite ends of cell
• Involved in Chromatid separation
• Spindle and Spindle Fibers form
• Football Shape, Cage like structures
• Fibers extend from them
• Vital role in Chromatid separation

11
Mitosis

• Metaphase---Second Phase
• Doubled Chromosomes attach to spindle fibers by
  their centromeres
• Chromosomes are pulled to the middle of the cell
• Each sister chromotid is attached to its own
  fiber which will pull them to different sides of
  the cell
• Ensures that each new cell receives an identical
  and complete set of chromosomes.

12
Mitosis

• Anaphase---3rd phase
• Separation of sister chromatids begins
• Centromeres split
• Chromatid pairs separate
• Pulled apart by the shortening of the
  microtubules in the spindle fibers

13
Anaphase
14
Mitosis

• Telophase---4th Phase
• Chromatids reach opposite poles of the cell
• Changes made in prophase are reversed
• Chromosomes unwind
• Start metabolic processes
• Spindle Fibers break down
• Nucleolus reforms
• Nuclear envelope forms

15
Telophase
16
Concept map

• Fill in where Mitosis belongs along with the
  four stages!

17
Cards ready

• In which stage of mitosis are the chromosomes
  pulled to the middle of the cell?
• a. Prophase
• b. Metaphase
• c. Anaphase
• d. Telophase
• In which stage of mitosis do the spindle and
  spindle fibers form?
• a. Prophase
• b. Metaphase
• c. Anaphase
• d. Telophase

18
Cards ready!

• In which stage of mitosis do the sister
  chromatids split?
• a. Prophase
• b. Metaphase
• c. Anaphase
• d. Telophase
• In which stage of mitosis do the nucleolus and
  nuclear envelope reappear?
• a. Prophase
• b. Metaphase
• c. Anaphase
• d. Telophase

19
Cytokinesis

• Dividing of cytoplasm
• Occurs after telophase
• Different in plants and animals
• Animals
• Plasma membrane pinches in along the equator
• Proteins under plasma membrane contract and slide
  past each other
• Continue to contract until cell in pinched in two
• Plants
• Plasma membrane does not pinch in
• Cell plate is laid down across the cells equator
• New membrane forms around each cell
• Cell wall forms on each side of the plate

20
Cytokensis

• Animal
• Plant

21
Cytokinesis
22
Concept map

• Fill in the concept map where Cytokinesis
  belongs!

23
MITOSIS
24
Results of mitosis

• Genetic continuity
• Growth and Repair
• Two new daughter cells with identical chromosome
  sets
• Unicellular organisms multiplied
• Multicellular organisms growth and reproduction
  results in tissues..organsorgan systemssurvival
  of organism.
• Work together to perform a specific function

25
Results of mitosis
2n
Parent Cell
2n
Daughter Cells
2n
26
Short Video of mitosis

• http//www.youtube.com/watch?vVlN7K1-9QB0